Adrenal Cortisol Support Complex by California Academy of Health

POSSIBLY EFFECTIVE

• Anxiety. Small clinical studies suggest that oral ashwagandha might reduce anxiety. Details: A meta-analysis of small randomized controlled trials in adults with anxiety and/or insomnia shows that taking ashwagandha 600-12,000 mg orally daily for 6-10 weeks moderately improves anxiety scores when compared with placebo. However, the validity of this study is limited by high heterogeneity (114787). One small clinical study in postal workers reporting moderate or severe anxiety shows that taking ashwagandha root (Swiss Herbals) 300 mg twice daily for 12 weeks, in combination with standard psychotherapy interventions, including dietary counseling, deep breathing exercise instruction, and a multivitamin, reduces anxiety scores when compared with standard psychotherapy interventions and placebo (19271). Additionally, two small clinical studies in adults with mild to moderate anxiety, depression, or stress show that taking a specific ashwagandha root extract standardized to contain 2.5% withanolides (Shagandha, Sabinsa Corp.) 500 mg with piperine 5 mg daily for 60-90 days reduces anxiety symptoms and perceived stress and improves sleep and quality of life when compared with placebo (113608,113609). However, another clinical study in young adults shows that taking a specific ashwagandha root and leaf extract (NooGandha, Specnova LLC) 225 mg or 400 mg daily for 30 days does not improve anxiety, stress, and depression scores when compared with placebo (107370).
• Generalized anxiety disorder (GAD). Oral ashwagandha may modestly improve symptoms of anxiety in patients with GAD. Details: Clinical practice guidelines from the World Federation of Societies of Biological Psychiatry (WFSBP) and the Canadian Network for Mood and Anxiety Treatments (CANMAT) provisionally recommend ashwagandha root extract at doses of 300-600 mg, standardized to 5% withanolides, daily as monotherapy or adjunctive therapy in patients with GAD. This recommendation is based on a review of three preliminary clinical trials with consistent results (110318). Two of these studies are described below. A small clinical trial in patients with GAD who are taking selective serotonin reuptake inhibitors (SSRIs) shows that taking ashwagandha 1 gram daily for 6 weeks reduces symptoms of anxiety by 48%, compared with a 27% reduction in patients taking placebo. Furthermore, by the end of treatment, 72% of patients taking ashwagandha were determined to have mild symptoms of GAD, compared with only 32% of those taking placebo (102687). Another preliminary clinical trial in patients aged 16 years and older with GAD shows that taking ashwagandha root powder granules 4 grams three times daily for 60 days moderately improves anxious mood in 58% of patients, compared with no moderate improvement in the placebo group. Mild improvement occurred in 82% of patients in the placebo group and 40% of patients in the ashwagandha group (90654). Another small clinical trial in adults with general anxiety disorder shows that taking ashwagandha, standardized to 35% withanolides, 60-120 mg orally daily for 60 days improves anxiety scores by about 60% when compared with placebo (114792).
• Insomnia. Oral ashwagandha may modestly improve sleep in patients with insomnia or non-restorative sleep. Details: A small meta-analysis in patients with insomnia and healthy patients shows that taking a specific ashwagandha root extract (KSM-66, Ixoreal Biomed) 250-600 mg daily or a specific root and leaf extract (Shoden, Arjuna Natural) 120 mg daily for 6-12 weeks modestly improves overall sleep, as well as sleep quality, sleep latency, total sleep time, wake time after sleep onset, and sleep efficiency, when compared with placebo. Effects were more pronounced in those with insomnia, with doses of at least 600 mg daily, and with treatment durations of at least 8 weeks (106784). These findings may be limited by heterogeneity of the included studies. A meta-analysis of 2 small randomized controlled trials in adults with anxiety and/or insomnia shows that taking ashwagandha 600 mg orally daily for 8-10 weeks modestly improves sleep onset latency, total sleep time, sleep efficiency, and sleep quality scores, but not wake after sleep onset or total time in bed, when compared with placebo. However, the validity of this study is limited by moderate heterogeneity (114787). In patients with non-restorative sleep, clinical research shows that taking a specific ashwagandha extract (Shoden, Arjuna Natural Private Ltd) 125 mg daily for 6 weeks increases sleep quality by 72%, compared with an improvement of 29% in patients taking placebo. Small to moderate improvements also occurred in total sleep time, sleep latency, and number of times awake (103476). Ashwagandha has also been evaluated as part of a combination treatment. A very small clinical trial in adults with poor quality sleep shows that taking milk fortified with ashwagandha 250-600 mg, or ashwagandha 250 mg and tryptophan, orally daily for 90 days moderately improves sleep quality scores when compared with placebo (114791). Additional data are needed to determine if the addition of tryptophan improves results more than ashwagandha alone.
• Stress. Oral ashwagandha seems to help reduce stress and may also reduce stress-related weight gain. Details: A meta-analysis of seven small clinical studies in healthy adults, patients with chronic stress, or patients with psychiatric conditions shows that taking ashwagandha 240-1000 mg daily for 8-12 weeks improves stress when compared with placebo (109587). Clinical studies, some of which are included in the meta-analysis mentioned above, evaluating adults with chronic stress show that taking specific ashwagandha root extracts 240 mg daily (Shoden, Arjuna Natural Ltd.), 300 mg twice daily (KSM-66, Ixoreal Biomed), or 500 mg daily (Shagandha, Sabinsa Corp.) with piperine 5 mg for 60 days, or a specific slow-release capsule containing ashwagandha root extract (Prolanza) 300 mg daily for 90 days reduces perceived stress and cortisol levels when compared with baseline and placebo (90652,95617,101816,102682,107371,113608). Additionally, a small clinical study in adults with stress and a related comorbidity, such as anxiety or depression, shows that taking ashwagandha root and leaf extract (Sensoril, Kerry Group) 125-500 mg orally daily for 8 weeks improves stress scores in a dose-dependent manner when compared with placebo (114112). In contrast, a moderate-sized study in adults with overweight or mild obesity with moderate-to-high levels of stress and fatigue shows that taking ashwagandha root extract (Witholytin, Verdure Sciences Inc) 200 mg twice daily for 12 weeks reduces stress when compared to baseline, but not when compared with placebo (113611).In healthy college students, clinical research also shows that taking ashwagandha root extract 350 mg twice daily for 30 days improves qualitative perceptions of stress management, but not stress scores, when compared with placebo (109589,109590). Other clinical research shows that taking ashwagandha root extract 500 mg twice daily may prevent stress-related weight gain when compared with placebo (95617).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Aging. A small clinical study suggests that oral ashwagandha may modestly improve well-being, sleep, and alertness in elderly patients. Details: A small clinical trial in individuals aged 65-80 years shows that taking ashwagandha root extract (KSM-66, Ixoreal Biomed) 600 mg daily for 12 weeks improves overall well-being, sleep quality, and mental alertness by small to moderate amounts when compared with placebo (102684).
• Androgenic alopecia. It is unclear if topical ashwagandha is beneficial for androgenic alopecia. Details: A small clinical study in adults with mild to moderate hair loss, including androgenic alopecia, shows that applying ashwagandha root extract serum (KSM-66, Ixoreal Biomed) 1-2 drops to the scalp daily for 75 days reduces hair shedding and increases hair density, growth, and thickness when compared with placebo (113613).
• Antipsychotic-induced metabolic side effects. It is unclear if ashwagandha is beneficial for attenuating the metabolic side effects of antipsychotic agents. Details: One preliminary clinical trial shows that taking a specific ashwagandha extract (Cap Strelaxin, M/s Pharmanza Herbal Pvt. Ltd.) 400 mg three times daily for one month reduces serum triglycerides by 12% and fasting blood glucose by 15% when compared with baseline levels. Patients were taking atypical antipsychotics and had modestly elevated triglycerides and fasting blood glucose levels at baseline (90649). The validity of these findings is limited by the lack of a comparator group.
• Asthma. Although there has been interest in using oral ashwagandha for asthma, there is insufficient reliable information about the clinical effects of ashwagandha for this condition.
• Athletic performance. It is unclear if ashwagandha is beneficial for improving athletic performance. Details: A meta-analysis of four small clinical trials shows that taking ashwagandha increases aerobic capacity in athletes and non-athletes based on the measurement of maximum oxygen consumption. Effective doses ranged from 500-1000 mg daily for up to 12 weeks (102683). Another meta-analysis shows that taking ashwagandha in doses of 120-1250 mg daily, as a single dose or divided twice daily, for up to 6 months seems to improve muscle strength, speed, time to exhaustion, recovery time, and cardiorespiratory fitness in athletes and non-athletes (105824). However, the validity of this analysis is reduced by the lack of a control group, the varied training levels of the subjects, and the wide range of outcomes assessed. A moderate-sized clinical trial in active adults shows that taking a specific ashwagandha root extract (KSM-66, Ixoreal Biomed) 300 mg orally twice daily, in addition to resistance training, for 8 weeks improves the maximum rate of oxygen consumption (VO2 max) as a measure of cardiorespiratory endurance, but not muscle strength when compared with placebo (114788). More research is needed to determine whether taking ashwagandha can improve athletic performance.
• Attention deficit-hyperactivity disorder (ADHD). Oral ashwagandha has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: In a preliminary clinical trial, children with ADHD were given a combination herbal extract formula (Nurture & Clarity), containing ashwagandha, white peony root, gotu kola, blue-green algae, bacopa, and sage, 3 mL three times daily for 4 months. Measures of attention, cognition, and impulse control improved significantly in children receiving ashwagandha when compared with placebo (19272). The dose of ashwagandha in the combination product was not reported, and the effect of ashwagandha alone in ADHD is unclear. Back pain.Oral ashwagandha has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical trial in adults with back pain shows that taking a specific combination product (Berelief, Monteloeder S.L.) containing ashwagandha 66%, rosemary, and sesame seed, 200-400 mg orally daily for 12 weeks moderately improves pain scores and reduces the need for adjunct pain medication when compared with placebo (114793). It is unclear if this effect is due to ashwagandha, other ingredients, or the combination.
• Bipolar disorder. It is unclear if oral ashwagandha is beneficial for improving cognitive function in adults with bipolar disorder. Details: Clinical research shows that taking ashwagandha extract (Sensoril, Natreon, Inc.) 250 mg daily for 1 week and then 250 mg twice daily for 7 weeks, improves some, but not all, measures of cognition by a small-to-moderate amount when compared with placebo (90653).
• Bronchitis. Although there has been interest in using oral ashwagandha for bronchitis, there is insufficient reliable information about the clinical effects of ashwagandha for this condition.
• Cerebellar ataxia. It is unclear if oral ashwagandha is beneficial for improving balance in patients with cerebellar ataxia. Details: A small, open-label study evaluating ashwagandha 500 mg three times daily in combination with Ayurvedic therapy for one month showed improvement in balance indices in subjects with cerebellar ataxia when compared with baseline (19273). The validity of this finding is limited by the lack of a comparator group. Additionally, it is unclear if this effect is due to ashwagandha, other ingredients, or the combination.
• Chemotherapy-related fatigue. Evidence is limited to one small clinical study in patients with breast cancer. Details: In preliminary clinical research in patients with breast cancer, taking ashwagandha powdered root extract 2 grams (Himalaya Drug Co) three times daily through six cycles of chemotherapy decreases chemotherapy-related fatigue when compared with no treatment. Fatigue scores were 16% to 52% higher in the control group when compared to the ashwagandha group (90651).
• Chronic obstructive pulmonary disease (COPD). It is unclear if oral ashwagandha is beneficial in patients with COPD. Details: A small clinical study in patients with stable COPD shows that taking ashwagandha root extract 250 mg twice daily for 12 weeks, along with conventional therapy, improves measures of lung function and exercise tolerance, but not quality of life, when compared with conventional therapy alone (109588).
• Cognitive function. Although there has been interest in using oral ashwagandha for cognitive function, there is insufficient reliable information about the clinical effects of ashwagandha for this condition.
• Constipation. Oral ashwagandha has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A very small clinical study in adults with constipation shows that taking a combination product containing ashwagandha root and ambrette fruit extracts 300 mg or 500 mg daily for 14 days improves bowel movement frequency and abdominal, rectal, and stool symptoms when compared with placebo (112114). Additionally, a moderate-sized clinical study in adults with functional constipation shows that using the same combination of ashwagandha and ambrette 300 mg or 500 mg daily for 60 days moderately improves constipation symptom scores and bowel movement scores when compared with placebo (114115). It is unclear if these effects are due to ashwagandha, ambrette, or the combination.
• Coronavirus disease 2019 (COVID-19). Oral ashwagandha has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in adults hospitalized with COVID-19 shows that taking a specific combination product, (Artovid-20, Bioved Pharmaceuticals) containing ashwagandha, ginger, turmeric, and Boswellia, 1,776 mg orally twice daily for 14 days shortens the duration of symptoms by 0.9 days when compared with placebo. Taking the combination product also modestly reduced the severity ratings of some symptoms, such as sore throat and cough, however, these improvements are unlikely to be clinically relevant (109899). Another small clinical study in adults with mild to moderate COVID-19 shows that taking ashwagandha 500 mg and ginger 1000 mg twice daily for 15 days reduces time to recovery by around 6 days and increases the rate of clinical cure 14-fold and 2.6-fold at days 5 and 7, respectively, when compared with a control. However, taking this combination does not appear to improve the proportion of patients with a negative COVID-19 test, viral clearance, serum antibodies, chest findings, or disease progression when compared with control (112094). The validity of these findings is limited by a lack of blinding, and the study may have been inadequately powered to detect a difference between groups. Other clinical research in adults hospitalized with mild to moderate COVID-19 shows that taking a specific combination product (Coroprotect) containing ashwagandha, pomegranate, turmeric, bacopa, licorice, and other ingredients, twice daily for 10 days improved cough, breathlessness, and fatigue symptoms when compared with placebo (114114). It is unclear if any effects are due to ashwagandha, other ingredients, or the combination.
• Depression. It is unclear if oral ashwagandha is beneficial for depression. Details: A small clinical study in adults with mild to moderate depression, anxiety, or stress shows that taking a specific ashwagandha root extract standardized to contain 2.5% withanolides (Shagandha, Sabinsa) 500 mg with piperine 5 mg daily for 90 days reduces the severity of depressive symptoms, improves sleep and quality of life, and increases serum serotonin levels when compared with placebo (113609).
• Diabetes. It is unclear if oral ashwagandha is beneficial for type 2 diabetes. Details: In patients with type 2 diabetes, preliminary clinical research shows that ashwagandha 3 grams daily for 30 days decreases blood glucose to a degree similar to oral hypoglycemic drugs (19274). However, this study did not compare ashwagandha directly to a group taking oral hypoglycemic drugs.
• Fatigue. It is unclear if oral ashwagandha is beneficial for fatigue. Details: A moderate-sized clinical study in adults with overweight or obesity and moderate-to-high levels of fatigue and stress shows that taking ashwagandha root extract (Witholytin, Verdure Sciences Inc.) 200 mg twice daily for 12 weeks reduces self-reported fatigue when compared with placebo (113611).
• Fibromyalgia. Although there has been interest in using oral ashwagandha for fibromyalgia, there is insufficient reliable information about the clinical effects of ashwagandha for this condition.
• Hiccups. Although there has been interest in using oral ashwagandha for hiccups, there is insufficient reliable information about the clinical effects of ashwagandha for this condition.
• Hypercholesterolemia. It is unclear if ashwagandha is beneficial for hypercholesterolemia. Details: A very small clinical study in subjects with hypercholesterolemia shows that ashwagandha 3 grams daily for 30 days decreases serum cholesterol, triglyceride, low-density lipoprotein (LDL) cholesterol, and very low-density lipoprotein (VLDL) cholesterol levels when compared with baseline (19274). The validity of these findings is limited by the lack of a comparator group.
• Hypothyroidism. It is unclear if ashwagandha is beneficial for hypothyroidism. Details: Preliminary clinical research in adults with subclinical hypothyroidism shows that taking a specific ashwagandha root extract (KSM-66, Ixoreal Biomed) 300 mg twice daily for 8 weeks increases triiodothyronine (T3) and thyroxine (T4) levels by 42% and 20%, respectively, and reduces serum TSH levels by 17% from baseline. These changes are significant when compared with placebo (97292). However, the effects of ashwagandha on thyroid hormone levels in patients with overt hypothyroidism, or in patients taking prescription thyroid hormones, is unknown.
• Infertility. Although there has been interest in using oral ashwagandha for infertility in females, there is insufficient reliable information about the clinical effects of ashwagandha for this condition.
• Lichen planus. It is unclear if topical ashwagandha is beneficial for oral lichen planus. Details: A small clinical study in adults with oral lichen planus shows that applying ashwagandha twice daily for 4 months reduces burning, pain, and lesion size when compared to baseline. Additionally, ashwagandha reduces these outcomes similarly to topical turmeric or aloe vera (115931). The validity of these findings is limited by the lack of comparison to placebo or standard or care.
• Male infertility. It is unclear if oral ashwagandha is beneficial for male infertility. Details: Preliminary clinical research in males with infertility shows that taking ashwagandha root powder for approximately 3 months modestly improves hormone levels, as well as sperm count and motility, when compared with baseline (19275,90650). The validity of these findings is limited by the lack of a comparator group. One study used a specific ashwagandha root extract (KSM-66 Ashwagandha, Ixoreal Biomed) 225 mg three times daily; another study provided doses of 5 grams daily (19275,90650).
• Menopausal symptoms. Oral ashwagandha may be beneficial for menopausal symptoms. Details: A small clinical study in healthy adults in perimenopause shows that taking a specific ashwagandha root extract (KSM-66, Ixoreal Biomed) 300 mg twice daily for 8 weeks improves menopausal symptom severity by 24%, compared with 11% in those receiving placebo. Quality of life and hot flashes also were improved in those taking ashwagandha (106785).
• Obsessive-compulsive disorder (OCD). It is unclear if ashwagandha is beneficial for OCD. Details: Preliminary clinical research shows that taking ashwagandha root extract 120 mg after meals for 6 weeks, in conjunction with prescribed selective-serotonin reuptake inhibitors (SSRIs), might reduce OCD symptom severity when compared with prescribed SSRIs alone. The dose was initiated at 30 mg daily and increased by 30 mg every 4 days. Although OCD scores were significantly reduced when compared with placebo, it should be noted that scores were already significantly lower in the placebo group at baseline (95618).
• Osteoarthritis. Oral ashwagandha has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: In patients with osteoarthritis, taking a specific combination supplement, containing ashwagandha 450 mg, Ayurvedic zinc complex 50 mg, guggul 100 mg, and turmeric 50 mg (Articulin-F) two capsules three times daily for 3 months reduces symptoms of pain and swelling when compared with placebo. However, there were no radiological improvements (19276). It is unclear if this effect is due to ashwagandha, other ingredients, or the combination.
• Parkinson disease. Oral ashwagandha has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: In patients with Parkinson disease, a small clinical study shows that taking a product containing ashwagandha 14.5 grams, cowhage 4.5 grams, Hyoscyamus reticulantus 0.75 grams, and Sida cordifolia 14.5 grams in lukewarm milk twice daily for 56 days improves symptoms like tremor, stiffness, and cramps when compared with baseline. The therapy followed 28 days of cleansing or eliminative therapy using Ayurvedic remedies (6899). The validity of these findings is limited by the lack of a comparator group. Also, it is unclear if these effects are due to ashwagandha, other ingredients, or the combination. Cowhage contains levodopa, which may contribute to any benefit seen with this combination product.
• Psychological well-being. It is unclear if oral ashwagandha is beneficial for improving psychological well-being in college students. Details: A small clinical study in healthy college students shows that taking ashwagandha root extract 350 mg twice daily for 30 days improves perceptions of well-being, including improvements in energy, mental clarity, food cravings, and sleep quality, when compared with placebo. Qualitative analysis also suggests these students had improvements in stress management, but stress scores were not reduced when compared with placebo (109589,109590).
• Rheumatoid arthritis (RA). It is unclear if oral ashwagandha is beneficial for improving symptoms of RA. Details: Preliminary clinical research shows that taking ashwagandha powder 5 grams twice daily for 3 weeks, followed by 4 weeks of sidh makardhwaj (a mixture of gold, mercury, and sulfur) 100 mg with honey daily, modestly improves symptoms in about 50% of males and 60% of females with RA when compared with baseline (95620). The lack of a control group limits the validity of this finding. Additionally, the effect of ashwagandha powder alone is unclear. Another small study in adults with RA shows that taking a combination product containing ashwagandha, ginger, black pepper, and colchicum luteum orally twice daily for 4 weeks does not improve RA disease scores when compared with celecoxib 100 mg orally twice daily (114785). However, the interpretation of these results is limited by poor methodology, and the study may have been inadequately powered to detect a difference between groups.
• Sexual dysfunction. Small clinical studies suggest that oral ashwagandha root extract may help improve sexual arousal and sexual desire in some females and males with sexual dysfunction. Details: Two, small clinical studies in adult females with sexual dysfunction show that taking ashwagandha root extract (KSM-66, Ixoreal Biomed) 300 mg twice daily with food for 8 weeks in conjunction with or without counseling increases the number of successful sexual encounters and improves orgasms, satisfaction, lubrication, and arousal when compared with placebo or counseling alone (95619,110492). Also, a small clinical study in adult males with low sexual desire shows that taking the same ashwagandha root extract 300 mg twice daily after meals for 8 weeks improves subjective sexual functioning scores, including measures of sexual arousal, sexual desire, sexual behavior, and orgasm, when compared with placebo (109586).
• Smoking cessation. Oral ashwagandha has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A moderate-sized clinical study in adults with a history of smoking 5 or more cigarettes daily for at least 3 years shows that taking a specific combination product containing ashwagandha 100 mg, Indian gooseberry, tribulus, bacopa, Albizia lebbeck, licorice, clove, ginger, cowhage, holy basil, and turmeric (Smotect, Smotect India) daily for 3 months reduces the number of cigarettes smoked daily and levels of alveolar carbon monoxide and carboxyhemoglobin but does not improve lung capacity when compared with placebo (112115). It is unclear if these effects are due to ashwagandha, other ingredients, or the combination.
• Tuberculosis. Although there has been interest in using oral ashwagandha for tuberculosis, there is insufficient reliable information about the clinical effects of ashwagandha for this condition.
• Vitiligo. Although there has been interest in using oral ashwagandha for vitiligo, there is insufficient reliable information about the clinical effects of ashwagandha for this condition.
• Wrinkled skin. It is unclear if topical ashwagandha is beneficial in individuals with wrinkled skin. Details: A small clinical study in healthy adults with photoaged skin shows that applying ashwagandha root extract 8% lotion daily for 60 days improves physician-rated scores for skin wrinkles, hydration, brightness, tone, and pigmentation and improves other measures of skin elasticity and hydration when compared with placebo. However, changes in melanin content did not differ between treatment groups (111538).
• Wound healing. Although there has been interest in using topical ashwagandha for healing of skin ulcers and skin sores, there is insufficient reliable information about the clinical effects of ashwagandha for this condition. More evidence is needed to rate ashwagandha for these uses.

(Read more about ASHWAGANDHA)

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Diabetes. It is unclear if oral banaba is beneficial in patients with type 2 diabetes. Details: One preliminary clinical study in patients with type 2 diabetes shows that a specific banaba extract (Glucosol), standardized to corosolic acid 1%, taken as 32 or 48 mg daily for 2 weeks is associated with 10% lower blood glucose levels when compared with placebo (11954). Another preliminary clinical study in patients with type 2 diabetes inadequately controlled by oral antidiabetic agents shows that taking a specific combination product containing extracts of banaba leaf and Padang cassia (Inlacin, Dexa Medica) 100 mg daily for 12 weeks reduces glycated hemoglobin (HbA1c) by 0.65% when compared with baseline (92849). The validity of this finding is limited by the lack of a comparator group. Additionally, it is unclear if this effect is due to banaba, Padang cassia, or the combination.
• Impaired glucose tolerance (prediabetes). Oral banaba has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in patients with impaired glucose tolerance shows that taking a specific combination product containing extracts of banaba leaf and Padang cassia (Inlacin, Dexa Medica) daily for 12 weeks preserves beta-cell function and insulin release and improves insulin sensitivity, but not 2-hour postprandial glucose levels, when compared with placebo. All patients received 50 mg once daily for 4 weeks, and those considered to be non-responders were titrated up to 100 mg once daily for the remaining 8 weeks (92848). It is unclear if these effects are due to banaba, Padang cassia, or the combination.
• Metabolic syndrome. It is unclear if oral banaba is beneficial in patients with metabolic syndrome. Details: A small clinical study in patients with metabolic syndrome shows that a specific banaba extract (MonoHerb), standardized to corosolic acid 1.13%, taken as 500 mg twice daily for 12 weeks improves systolic blood pressure, fasting blood glucose, triglycerides, and very low-density lipoprotein (VLDL) cholesterol when compared with baseline (108617). The lack of statistical comparison to the placebo group limits the validity of these findings. More evidence is needed to rate banaba for these uses.

(Read more about BANABA)

EFFECTIVE

• Dyspepsia. Oral calcium carbonate is approved by the US Food and Drug Administration (FDA) as an antacid. Details: Taking calcium carbonate orally as an antacid is effective for treating dyspepsia (1843). Calcium carbonate has FDA approval as an antacid.
• Hyperkalemia. Intravenous calcium gluconate is approved by the US Food and Drug Administration (FDA) for preventing hyperkalemia-induced cardiac abnormalities. Details: Administering calcium gluconate intravenously can reverse electrocardiographic changes and arrhythmias induced by hyperkalemia (12946). Intravenous calcium gluconate is FDA-approved for preventing hyperkalemia-induced cardiac abnormalities.
• Hypocalcemia. Oral calcium treats and prevents hypocalcemia. Intravenous calcium is used to treat severe hypocalcemia. Details: Taking calcium orally is effective for treating and preventing hypocalcemia. Intravenous calcium gluconate, acetate, gluceptate, or chloride is effective for severe hypocalcemia or hypocalcemic tetany (12928).
• Kidney failure. Oral calcium carbonate or calcium acetate is used as a phosphate binder during kidney failure. Details: Taking calcium carbonate or calcium acetate orally is effective as a phosphate binder. Calcium acetate (PhosLo) appears to control hyperphosphatemia better than sevelamer (Renagel) (12943,12944,38990). Calcium citrate is not recommended for this purpose because it increases aluminum absorption and does not bind phosphate as efficiently as calcium acetate or calcium carbonate (21631). Some clinical research also shows that taking calcium orally reduces blood pressure in patients with kidney failure (975).

LIKELY EFFECTIVE

• Corticosteroid-induced osteoporosis. Oral calcium in combination with vitamin D prevents bone density loss that occurs during long-term treatment with corticosteroids. Details: Taking calcium in combination with vitamin D as adjunctive therapy seems to be effective for reducing bone mineral density loss in people using corticosteroids long-term (982,1046,1830,1831,1832,4462,4463,4464,4465,4466)(4467,12945,38493). One specific product used in clinical research is Oscal (Marion Merrel Dow Inc.), which contains elemental calcium 500 mg per tablet plus vitamin D 125 IU per tablet (982). Another product used is Oscal 250 + D (SmithKline Beecham Healthcare), which contains elemental calcium 250 mg and vitamin D 125 IU per tablet (1046).
• Hyperparathyroidism. Oral calcium reduces parathyroid hormone levels in patients with secondary hyperparathyroidism due to kidney failure. Details: Taking calcium orally reduces parathyroid hormone levels in patients with kidney failure and secondary hyperparathyroidism (1827,1828,1829,39174,39425). In elderly women, the combination of calcium and vitamin D reverses secondary hyperparathyroidism and reduces hip fracture risk (8818). Also, population research suggests increased calcium intake from the diet and supplements reduces the risk of primary hyperparathyroidism in women. Supplemental intakes of at least 500 mg/day and dietary intakes of approximately 1100 mg/day are considered to be protective (91353).
• Osteoporosis. Adequate calcium intake, from the diet and/or supplements, is recommended for the prevention and treatment of osteoporosis. Details: The Bone Health and Osteoporosis Foundation (BHOF) recommends ensuring adequate calcium intake in line with the recommended dietary allowance (RDA) by age, along with adequate vitamin D intake, for the prevention and treatment of osteoporosis in adults over 50 years of age. Supplementation can be used to augment dietary intake when adequate dietary intake is not feasible (109425). In the US and Canada, foods containing at least 200 mg calcium with less phosphorous content than calcium can be labelled with a health claim regarding the relationship between adequate calcium intake and a reduced risk for osteoporosis (11940,102148). However, calcium supplementation is not recommended specifically for the primary prevention of osteoporosis. The US Preventive Task Force (USPSTF) states that the current evidence is insufficient to assess the balance of benefits and harms of vitamin D and calcium supplementation, alone or in combination, for the primary prevention of fractures in community dwelling adults without osteoporosis (95695). Also, calcium supplements do not seem to be effective for preventing loss of bone mineral density (BMD) during lactation (988), in patients who have had bone marrow transplantation (1817), or in patients who have had renal transplantation (4823,38736,38871). Maximal bone growth occurs in the teenage years, and then BMD in females remains relatively constant until age 30-40. After age 40, bone loss typically occurs at rates of 0.5% to 1% per year. In males, this occurs several decades later. Bone loss is more pronounced if dietary calcium intake is below the RDA, which is the case for many Americans (2571,2578). One meta-analysis of randomized controlled trials in healthy children 7-14 years old shows that fortifying food with calcium 250-1000 mg daily for up to 24 months modestly improves femoral neck BMD, but not hip or spine BMD. However, the included trials did not supplement vitamin D (107232). During the 5 years immediately after menopause, calcium supplementation has very little effect on bone loss (2569,2570,2575,2576). The rapid loss of estrogen causes a high bone resorption rate, which increases serum calcium levels and therefore decreases intestinal absorption of calcium (2570). After this period, the typical rate of bone loss is 2% per year (2572,2576). Taking calcium 1000-1600 mg daily as carbonate, citrate, lactate gluconate, or citrate malate salt decreases this rate by 0.25% to 1% annually (977,979,981,2569,2571,2572,2575,2576,2578,6850)(38978,38980,39064). The greatest reductions (1% or more) are seen in the first 1-2 years of supplementation when bone remodeling foci can be filled (2569,2576). After this period, the differences in rate of loss between supplemented and non-supplemented females are closer to 0.25% per year (2569,2577). A meta-analysis of clinical evidence suggests that there is no additional benefit after 4 years (38980). Small clinical studies have found that continuous calcium supplementation at an average daily dose of 1050 mg, started after menopause and continued for 1.5-4 years, may reduce fracture rates by 26% when compared with no calcium supplementation. The largest of these studies was conducted in nursing home residents who also received daily vitamin D; the benefits of calcium, specifically, are unclear (39386). Some research also suggests that calcium and vitamin D improves primary prevention of osteoporotic fractures in some older individuals with osteoporosis, particularly the elderly and those who are no longer community dwelling (12930,38875,38849,39026,109471). However, not all research is positive. One large clinical trial in elderly adults with a low-trauma fracture show that taking calcium 1000 mg daily with or without vitamin D 800 IU daily for 2-7 years does not reduce the risk of a second fracture when compared with placebo (13073). Another clinical study shows that taking calcium 1000 mg daily plus vitamin D 800 IU daily does not prevent a second fracture in elderly patients, or prevent a first fracture in elderly patients with other risk factors such as low body weight (less than 58 kg, 127.6 pounds), smoking, family history of hip fracture, or fair or poor self-reported health (12929). Also, some exploratory research suggests that supplements may need to be continued indefinitely; in adults over 68 years of age, any effects of 2 years of calcium supplements on BMD appear to be lost within 2 years after discontinuing supplements (6853). Calcium has additive effects when used with other agents such as vitamin D, estrogens, or calcitonin. Whereas calcium alone generally reduces or prevents loss of BMD, combination with other agents can produce small increases in BMD ranging from 0.3% to 3.3% depending on the combination and dosages used (978,980,1836,2570,2571,2572,2576). However, one meta-analysis in healthy adults shows that fortifying foods with calcium 250-1000 mg daily, in conjunction with vitamin D supplementation, for up to 24 months does not improve BMD when compared with control (107232). The full potential of osteoporosis treatments cannot be realized without adequate calcium intake (2569,2570,2571,2572). Advise patients taking agents such as estrogens, calcitonin, bisphosphonates, or raloxifene (Evista) to ensure that their daily calcium intake meets the RDA. Use supplements if necessary. The usefulness of calcium in preventing osteoporosis in males is not as well-studied. Some observational research has found that calcium 870 mg daily is not associated with changes in BMD and bone loss in males (97201). However, clinical evidence suggests that taking calcium 1000 mg daily for 2 years might improve trabecular or cortical bone mass by 2% to 4% (980,8827,8873). Dietary supplementation with calcium and vitamin D seems to moderately reduce bone loss measured in the femoral neck, spine, and total body, and seems to reduce the incidence of nonvertebral fractures in older patients with osteopenia or low BMD (980).
• Premenstrual syndrome (PMS). Adequate calcium intake seems to prevent symptoms of PMS. Details: There seems to be a link between low dietary calcium intake and symptoms of PMS (2004,6847,39007). Taking calcium 1000-1336 mg daily seems to significantly reduce depressed mood, water retention, and pain, especially if daily calcium intake is inadequate (1822,1823,1824,2004,95821). Calcium carbonate 1200 mg daily seems to decrease PMS symptom scores by about 18% when compared with placebo (1822). Increasing dietary calcium intake is also associated with a decreased risk of developing PMS. Consuming an average of 1283 mg of calcium per day from foods is associated with about a 30% lower risk of developing PMS compared with consuming an average of 529 mg daily (13094); however, taking calcium supplements does not appear to be associated with the risk of developing PMS.

POSSIBLY EFFECTIVE

• Colorectal cancer. Oral calcium seems to be beneficial for preventing colorectal cancer, especially in those with adequate vitamin D levels and normal body mass index (BMI). Details: Population studies have found that increased intake of dietary or supplemental calcium is associated with a reduced risk of colorectal cancer and colorectal adenomas (1047,8820,12120,38951,98898,98899). Clinical trials and meta-analyses of clinical research also show that taking calcium supplements 1.2-2 grams daily for up to 4 years can reduce the risk of colorectal adenoma recurrence by up to 29% (970,12118,12950,15267,34596,38718,39042,95817). However, not all research has been positive. Some meta-analyses of clinical research or observational studies suggest that taking calcium does not reduce the risk of familial adenomatous polyposis or colorectal cancer (34596,39042,39349). Other contradictory research suggests that postmenopausal females who take calcium 1000 mg daily plus vitamin D 400 IU daily do not have a reduced risk of developing colorectal cancer (14290); however, this finding may not be reliable due to the high baseline intake of calcium in study participants. The reason for these conflicting findings is not entirely clear. Vitamin D might be an important factor. People with lower than average vitamin D levels do not seem to get any benefit from calcium supplements (12118). Also, one meta-analysis of previous trials suggests that taking calcium 1200 mg daily reduces the risk of colorectal adenomas in people with a normal BMI, but not in those who are overweight or obese (99715). Despite this conflicting evidence, the US Food and Drug Administration (FDA) approved a qualified health claim in 2005 stating that calcium supplements may reduce the risk of colorectal cancer and colorectal adenomas. However, the FDA has determined that there is little scientific evidence to support this claim (102366).
• Fetal bone mineralization. If calcium intakes are low during pregnancy, oral calcium seems to be beneficial for increasing fetal bone density. Details: With low dietary calcium intake (less than 562 mg elemental calcium daily) during pregnancy, calcium supplementation increases fetal bone mineralization and density. However, calcium supplementation does not offer any additional benefit if calcium intakes are adequate (3263,3264).
• Hypertension. Oral calcium seems to reduce blood pressure by a small amount in adults with or without hypertension. However, it is unclear if this reduction is clinically significant. Details: Many clinical trials and observational studies, including a meta-analysis of 18 high-quality clinical trials, show that intake of calcium supplements or dietary calcium modestly reduces systolic blood pressure in patients with or without hypertension, usually around 1-2 mmHg. Calcium seems to be more effective for certain subpopulations of patients, such as those who are salt-sensitive or have low baseline dietary calcium intake (945,972,974,976,984,1818,1819,1820,1821,6852)(13138,14406,38803,39063,39094,39221,113920,113925). However, a large-scale clinical trial in postmenopausal females shows that taking vitamin D (cholecalciferol) 400 IU daily in combination with elemental calcium 1000 mg daily does not lower blood pressure or reduce the risk of developing hypertension (16714). Additionally, a meta-analysis of 8 clinical trials shows that taking calcium in combination with vitamin D for up to 7 years has no effect on blood pressure (98861). The validity of this finding is limited by the poor methodological quality of the included studies. Some observational research suggests that calcium can reduce the risk for hypertension. Population research in females aged 45 years and older suggests that higher intake of calcium from both diet and supplemental sources is linked to a lower risk of developing hypertension when compared to lower calcium intake (14265). In 2005, the US Food and Drug Administration (FDA) approved a qualified health claim stating that calcium supplements may reduce the risk of hypertension. However, the FDA has concluded that this claim is based on supporting, rather than conclusive, evidence (102367). Research evaluating the effect of calcium supplementation during pregnancy on the child's blood pressure has yielded conflicting findings. A systematic review of 2 clinical studies and 3 observational studies found that calcium intake during pregnancy is associated with a 1-2 mmHg reduction in the systolic blood pressure of the offspring between the ages of 1-7 years (38852). However, a separate meta-analysis of 3 clinical studies shows that calcium intake during pregnancy does not reduce systolic or diastolic blood pressure in the offspring (113923).
• Osteomalacia. Oral calcium seems to reverse osteomalacia caused by very low calcium intakes. Details: Osteomalacia is commonly caused by vitamin D deficiency; however, very low calcium intake can also lead to osteomalacia in children and adults. Calcium supplementation can reverse osteomalacia caused by calcium deficiency. Along with appropriate vitamin D supplementation, individuals at risk of osteomalacia need sufficient calcium intake (94819).
• Pre-eclampsia. Oral calcium seems to reduce the risk of pre-eclampsia, especially in high-risk individuals and those with low baseline dietary calcium intake. Details: Although there is some conflicting evidence (971,38756), most clinical research shows that taking calcium orally 1-2 grams daily reduces the risk of pre-eclampsia (973,1833,8828,39043,39319,39426,97348,113919). A large clinical trial of 11,000 pregnant individuals in India and Tanzania shows that supplementation with 500 mg daily is similarly effective to 1500 mg daily (113908). Multiple meta-analyses which include 16-30 clinical studies have found that varying doses of calcium supplementation reduce the relative risk of pre-eclampsia by 46% to 51% when compared with placebo (97348,113909,113919). One of these meta-analyses found that for every 19 females treated with calcium, one episode of pre-eclampsia would be avoided (97348). Additionally, one of these meta-analyses found that calcium reduces the relative risk of pre-eclampsia by 51%, regardless of whether it is taken at a dose above or below 1000 mg daily (113919). Some research suggests that calcium supplementation may have a greater effect in individuals at high risk of pre-eclampsia or with low baseline dietary calcium intake, and when taken at greater than or equal to 20 weeks of gestation (15029,38497,97348,99714,113919). However, another meta-analysis of 30 clinical studies found a similar benefit of calcium in both high- and low-risk individuals (113919). A separate meta-analysis of 6 clinical studies conducted in China evaluated the benefits of calcium carbonate 500-600 mg daily taken in conjunction with aspirin 50-75 mg daily during pregnancy. This combination was associated with an 80% lower relative risk of pre-eclampsia and an 83% lower relative risk of pre-eclampsia with gestational hypertension when compared with routine care (113913). In 2005, the US Food and Drug Administration (FDA) approved a qualified health claim regarding the use of calcium supplements to reduce the risk of pregnancy-induced hypertension and pre-eclampsia. However, due to the limited and conflicting research available at that time, the FDA stated that this outcome was highly unlikely (102366). Since then, large, high-quality clinical research has supported this finding. In fact, in 2016 the World Health Organization (WHO) released a recommendation to prescribe oral calcium 1.5-2 grams daily during pregnancies at high risk of pre-eclampsia if dietary calcium intakes are low (97347).
• Pregnancy-induced hypertension. Oral calcium may reduce the risk of pregnancy-induced hypertension. Details: A meta-analysis of 17 clinical studies shows that calcium supplementation during pregnancy may reduce the relative risk of pregnancy-induced hypertension by 30% when compared with control (113909). A separate meta-analysis of 6 clinical studies conducted in China, which evaluated the benefits of calcium carbonate 500-600 mg daily taken in conjunction with aspirin 50-75 mg daily during pregnancy, shows that this combination reduces the relative risk of pregnancy-induced hypertension by 85% when compared with routine care (113913).
• Rickets. Oral calcium seems to reverse rickets caused by very low calcium intakes. Details: Rickets is commonly caused be vitamin D deficiency; however, very low calcium intake can also lead to rickets. Calcium supplementation can reverse rickets caused by calcium deficiency (94819). A small clinical study in children with nutritional rickets shows that taking calcium 500-2000 mg daily for 24 weeks improves radiographically measured rickets caused by calcium deficiency. Rickets seems to improve more rapidly with calcium 1000 mg compared to calcium 500 mg. However, increasing the calcium dose to 2000 mg daily is not more beneficial than calcium 1000 mg daily (98904).
• Tooth retention. Oral calcium with vitamin D seems to help with tooth retention in the elderly population. Details: A clinical trial in the elderly population shows that taking calcium citrate malate 500 mg daily along with vitamin D3 (cholecalciferol) 700 IU daily orally for 3 years reduces the risk of tooth loss by about 52% when compared with placebo (8816).

POSSIBLY INEFFECTIVE

• Breast cancer. Oral calcium, via supplementation or as part of the diet, does not seem to be beneficial for breast cancer prevention. Details: Although some studies disagree (15631,39041,95811,107237,113917), most population research suggests that increased calcium intake is not associated with overall breast cancer risk (15631,16715,98895,107236,107237,113917). However, one meta-analysis of observational studies shows that although higher total calcium intake is not associated with breast cancer risk, higher dietary calcium intake, specifically, may be associated with a slightly reduced risk (113917). Also, some analyses suggest that calcium intake may be associated with the risk for certain breast cancer sub-types. Some subgroup analyses suggest that calcium intake may reduce the risk of breast cancer in postmenopausal, but not pre-menopausal, adults (15631,107237) and that dietary calcium intake may reduce estrogen receptor(ER)-negative breast cancer, but not ER-positive breast cancer (107236). However, most research has not evaluated the effects of calcium supplementation or intake on breast cancer subtypes. The best evidence to date, from a large scale clinical trial (Women's Health Initiative), shows that taking vitamin D (cholecalciferol) 400 IU daily plus calcium 1000 mg daily for 7 years after menopause does not reduce the risk of developing invasive breast cancer at the end of the study and 5 years after the end of the intervention (16715,98895).
• Fractures. Although oral calcium prevents fractures in osteoporosis, most evidence shows that calcium does NOT prevent factures in people who do not have osteoporosis. See Osteoporosis discussion for more information on the use of calcium for this purpose. Details: Robust meta-analyses of mostly large, high-quality clinical studies show that calcium supplementation 500-1600 mg daily for 0.5-7 years with or without vitamin D does not reduce total fractures, hip fractures, vertebral fractures, or non-vertebral fractures in older adults without osteoporosis (95822,112486). A large-scale study in postmenopausal females aged 50-79 years who were enrolled in the Women's Health Initiative (WHI) suggests that calcium 1000 mg plus vitamin D 400 IU daily for 7 years only modestly improves bone mineral density (BMD) and does not significantly reduce fracture risk. This lack of effect may have been due to low adherence to the treatment regimen. In those who were 80% adherent, the combination of calcium plus vitamin D reduced the risk of hip fracture by about 29% (14282). Also, some clinical research shows that taking calcium carbonate 1000 mg and vitamin D 400 IU for 5 years does not attenuate loss of height after menopause when compared with placebo (95810). Additional meta-analyses of clinical and observational evidence suggest that calcium supplementation is not associated with a reduced risk of vertebral or nonvertebral fractures, such as hip fractures (38589,38888,98895). Some other research has suggested that calcium in combination with vitamin D reduces fracture risk in older patients without osteoporosis (980,1836,8818,12930,12933,12952,38849,102145,107235); however, this research is confounded by a number of variables, including the presence of hormonal therapy and differing levels of fracture risk at baseline (1836,8818,95822). Conflicting findings on this topic might also be due to genetic differences in patient populations. A population analysis of the WHI study found that, in older females with the lowest genetic susceptibility to low BMD, taking calcium with vitamin D is associated with a reduction in fracture risk. However, in females with a higher genetic susceptibility to low BMD, there is no association between supplementation and fracture risk. This might be because individuals with a lower susceptibility to low BMD are also more responsive to calcium and vitamin D supplementation (97357). As of April 2018, the U.S. Preventative Services Task Force (USPSTF) concludes that there is insufficient evidence to determine whether supplementing with vitamin D >400 IU daily along with calcium >1000 mg daily is safe and effective for preventing fractures in community dwelling adults without vitamin D deficiency, osteoporosis, or a history of fracture. USPSTF recommends against supplementing with calcium 1000 mg daily or less along with vitamin D 400 IU daily or less for preventing primary fractures in community-dwelling postmenopausal females (95695).
• Obesity. Oral calcium does not seem to improve weight loss in adults or children with overweight or obesity. Details: Observational research has found that adults and children with low calcium intake are more likely to gain weight, have a higher body mass index (BMI), and be overweight or obese when compared to people with high calcium intake (12124,12125,12126,12127,14265). Additional observational research has found that increasing calcium intake is associated with weight loss in females; the results in males have been conflicting (12127,15602,15603). Despite these findings from observational research and a few small clinical studies (12128,15397,14438,98905,113918), most clinical research has found that increased calcium intake does not increase weight loss (12052,13138,15396,15399,38985,39004,97356). A meta-analysis of 20 clinical studies shows that daily dietary and supplemental calcium intake that meets the dietary reference intake (DRI) of 1000 mg or more daily does not increase weight loss in overweight individuals or patients with obesity when compared with intake below the DRI (95813). An older meta-analysis of 13 clinical trials also shows that increased dietary and supplemental calcium intake does not increase weight loss (15605).
• Overall mortality. Oral calcium does not seem to reduce overall mortality. Details: While some population research has found that calcium taken in combination with vitamin D in older females is associated with a lower risk of death (97353), most evidence shows that calcium, with or without vitamin D, has no effect on all-cause mortality (93533,97308,113584).

INEFFECTIVE

• Cardiovascular disease (CVD). Oral calcium does not reduce the risk of developing CVD and may actually increase risk in some patients. Details: Clinical research shows that calcium does not decrease CVD risk. Several separate meta-analyses of clinical and population research involving over 50,000 patients show that taking calcium 600-1200 mg daily for up to 7 years does not reduce the risk of CVD-related outcomes, including stroke and myocardial infarction, cardiovascular death, or overall mortality (39018,91350,92994,93533,97308,98902,107231,107233). No association was found between total dietary or supplemental calcium intake with or without vitamin D and the risk of CVD or mortality (91350,93533,97308). In fact, some population and clinical research has found that when calcium is used alone or with vitamin D, there is an INCREASED risk of CVD and coronary heart disease (38077,107233). However, other clinical research disagrees (93533). One meta-analysis of high-quality randomized controlled trials shows that taking calcium for 2-7 years increases the risk of CVD and coronary heart disease by 1.1-1.2 times when compared with control. However, the majority of the included research evaluated postmenopausal females and it is unclear if this finding is applicable to other populations (107233).
• Chemotherapy-induced peripheral neuropathy. Intravenous calcium does not prevent nerve pain in patients given oxaliplatin. Oral calcium has not been evaluated for this purpose. Details: While pooled analyses of cohort studies and randomized controlled trials suggest that calcium and magnesium infusion decreases the incidence of oxaliplatin-induced neurotoxicity, a meta-analysis of only randomized controlled trials shows that the infusion has no effect in preventing neurotoxicity (90028,90029,90031). Additionally, clinical trials show that administering calcium gluconate 1 gram with magnesium sulfate 1 gram intravenously immediately before, or before and after, the administration of a single oxaliplatin cycle (90005), or over the entire 6-cycle course of oxaliplatin, does not improve symptoms of neurotoxicity when compared with placebo (96474).
• Myocardial infarction (MI). Oral calcium does not prevent MI. When taken in the absence of vitamin D, oral calcium may increase the risk of MI. Details: Population research has found that increased dietary intake of calcium is associated with a decreased risk of MI (91350). However, a 2010 meta-analysis of clinical research shows that taking calcium at a dose of at least 500 mg daily is associated with an approximate 30% INCREASE in the risk of MI in patients over the age of 40. According to this analysis, one additional case of MI will occur for every 69 patients that take calcium for 5 years (17482). A more recent meta-analysis of high-quality randomized controlled trials shows that taking calcium for 2-7 years increases the risk of MI by 1.2 times when compared with control. However, the majority of the included research studied postmenopausal females and it is unclear if this finding is applicable to other populations (107233) In contrast, other meta-analyses of clinical research have shown that taking calcium for up to 7 years is NOT associated with an increased risk of MI, including a meta-analysis that only included postmenopausal females (93533,107231). Reasons for these discrepancies are not entirely clear. It may relate to whether calcium is taken as monotherapy or in combination with vitamin D. When taken with vitamin D, which is commonly recommended, calcium supplementation does not appear to be associated with an increased risk of MI in postmenopausal females (93533). Also, the association between calcium supplementation and MI risk may be influenced by the amount of calcium consumed as part of the diet. Supplementation with calcium may be associated with an increased risk of MI in people with dietary calcium intake above 805 mg daily, but not in those with dietary calcium intake below 805 mg daily (17482)

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Alcohol use disorder. It is unclear if oral calcium is beneficial for alcohol use disorder. Details: Preliminary clinical research shows that taking calcium carbonate 800 mg and vitamin D 200 IU orally daily for 14 days modestly reduces alcohol craving scores and withdrawal scores when compared with placebo in adults with alcohol dependence that are undergoing withdrawal. Taking calcium carbonate did not reduce the need for diazepam; however, the study may have been inadequately powered to detect a difference between groups (107234).
• Atherosclerosis. It is unclear if oral calcium is beneficial for atherosclerosis. Details: A population study has found that taking calcium 1.2 grams daily for 3 years has no effect on carotid intima thickness or carotid atherosclerosis incidence. A total calcium intake (dietary and supplemental) of at least 1794 mg daily in older females may be associated with a decreased risk of carotid atherosclerosis when compared with a total calcium intake below 1010 mg daily (97351).
• Autism spectrum disorder. It is unclear if oral calcium during pregnancy is beneficial for reducing the odds of autism spectrum disorder in the offspring. Details: A small observational study found that calcium supplementation during pregnancy is associated with a 52% reduced odds of an autism spectrum disorder in the offspring (98900).
• Brain tumor. It is unclear if dietary calcium intake is associated with risk of brain tumor. Details: A meta-analysis of 4 case-control studies has found that higher dietary calcium intake is associated with a lower odds of brain tumor when compared with lower dietary intake (113922). The validity of this finding is limited by the exploratory nature of the included studies, which analyzed all dietary ingredients for any potential associations.
• Cancer. Oral calcium alone does not seem to prevent cancer. It is unclear if oral calcium with vitamin D is beneficial for preventing cancer. Details: Taking calcium alone does not seem to significantly reduce the risk of cancer (12118,15629). The role of calcium in cancer prevention when taken along with vitamin D is controversial, as conflicting results exist. One clinical trial shows that healthy postmenopausal females who take supplemental calcium 1400-1500 mg daily plus vitamin D3 (cholecalciferol) 1100 IU daily have a 60% lower relative risk for developing cancer of any type. Approximately 25 postmenopausal females would need to take this combination for 4 years to prevent one occurrence of cancer (15629). However, a more recent clinical study shows that healthy postmenopausal females who take supplemental calcium 1500 mg daily plus vitamin D3 (cholecalciferol) 2000 IU daily do not have a reduced risk of cancer at 4 years (93943). Reasons for the disparate results are not entirely clear. The discrepancies do not appear to be related to baseline vitamin D levels or different study populations. It is possible that, given the 10-year time lapse between the two publications, the discrepancies result from differences in cancer detection capability. Also, since cancer risk was a secondary outcome measure in the earlier study and a primary outcome measure in the more recent study, it is possible that the discrepancies result from differences in statistical methodologies. The effect of vitamin D and calcium on cancer risk in males and younger patients is not known. There is also interest in using calcium for reducing the risk of hematological malignancies. An analysis of the Women's Health Initiative study shows that taking calcium 1000 mg daily in combination with vitamin D3 400 IU for up to 10 years is associated with a 20% reduction in the risk of hematologic malignancies when compared with placebo. However, no effect on hematologic malignancy related mortality was seen (97354).
• Depression. It is unclear if oral calcium is beneficial for depression prevention. Details: Population research has found no association between a higher dietary intake of calcium and the risk of depression when compared with a lower dietary intake of calcium (96480).
• Diabetes. It is unclear if dietary calcium intake is associated with type 2 diabetes risk. Details: Some population research has found that a higher intake of calcium from the diet or supplements, alone or in combination with vitamin D, is associated with a lower risk of developing type 2 diabetes when compared with lower calcium intake (14265,16713,96473,113929). One meta-analysis of cohort and cross-sectional studies found that the highest level of dietary calcium intake is associated with an 18% relative reduction in risk of type 2 diabetes when compared with the lowest level of intake. A dose-response analysis suggests that each 300, 600, and 1000 mg per day increase in dietary calcium intake is associated with a 7%, 14%, and 23% reduced risk of type 2 diabetes, respectively (113929). However, population research is often limited by confounding variables. For example, one analysis suggests that any beneficial effect might be influenced by concomitant magnesium intake (96473,113929), while another suggests that any benefit from increased intake may be more pronounced in females, adults aged 50 years or older, and Asian populations (113929). Furthermore, other population research has found that serum calcium levels higher than 9.6 mg/dL are associated with greater risk of developing diabetes in Chinese adults with osteoporosis (95815).
• Dyslipidemia. It is unclear if oral calcium is beneficial for dyslipidemia. Details: One clinical study in adults with mild to moderate hypercholesterolemia shows that adding calcium carbonate 400 mg three times daily to a low-fat diet (American Heart Association Step 1) for 6 weeks reduces low-density lipoprotein (LDL) cholesterol levels by 4% and increases high-density lipoprotein (HDL) cholesterol levels by 4% when compared with the low-fat diet and placebo (2557). In contrast, a clinical study in females with dyslipidemia shows that taking calcium 800 mg daily for 2 years INCREASES total cholesterol levels and carotid intima-media thickness in postmenopausal, but not premenopausal, females when compared with placebo (97350). Calcium supplementation has also been evaluated in combination with vitamin D. A meta-analysis of randomized controlled trials including adults with normolipidemia and dyslipidemia shows that taking calcium 500-2000 mg daily and vitamin D 200-7142 IU daily modestly improves HDL cholesterol and triglyceride levels, but not LDL cholesterol levels, when compared with placebo. Subgroup analyses suggest that calcium and vitamin D supplementation is most beneficial in patients with dyslipidemia at baseline (107227). The relationship between dietary calcium intake and serum lipid levels has also been evaluated in observational research. A meta-analysis of 7-11 observational studies found that dietary calcium intake is not associated with total cholesterol levels, although small differences in individual lipid parameters were identified. Additionally, a meta-analysis of 4-9 observational studies suggests that calcium intake is not associated with the risk of developing hypertriglyceridemia, hypercholesterolemia, or low HDL. A subgroup analysis found that higher calcium intake may be associated with lower triglyceride levels in Asian populations (113927). Overall, these findings are limited by significant heterogeneity and the cross-sectional nature of the included studies.
• Dysmenorrhea. It is unclear if oral calcium is beneficial for reducing pain associated with dysmenorrhea. Details: Clinical research shows that taking calcium carbonate 1000 mg with vitamin D 5000 IU daily for three menstrual cycles does not reduce pain when compared with placebo in patients with primary dysmenorrhea (95821). However, calcium carbonate 1000 mg taken alone seems to reduce pain when compared with placebo.
• Endometrial cancer. It is unclear if oral calcium is beneficial for endometrial cancer prevention. Details: A meta-analysis of population research suggests that calcium supplements may reduce the risk of endometrial cancer, but dietary calcium does not seem to have any effect (38893).
• Exercise-induced muscle damage. It is unclear if oral calcium is beneficial for reducing exercise-induced muscle damage. Details: A very small clinical study in resistance-trained adults shows that taking calcium carbonate 500 mg 4 times daily for 3 weeks does not attenuate exercise-induced muscle damage from bench presses when compared with placebo (113933). This study may have been inadequately powered to detect a difference between groups.
• Fall prevention. It is unclear if oral calcium with vitamin D is beneficial for preventing falls. Details: Research suggests that calcium in combination with vitamin D, but not calcium alone, might prevent falls by decreasing body sway and normalizing systolic blood pressure (6362,11939,39038). Some experts think the combination of calcium and vitamin D may be important (11916). Preliminary clinical research in adults residing in a health care facility shows that taking vitamin D supplements while increasing dietary calcium and protein for 2 years reduces falls by 11% when compared with standard diets. Intervention diets were supplemented with milk, yogurt, and cheese to provide calcium 1142 mg and protein 69 grams daily (107235). There might also be different effects in females compared to males. In one study, females aged 65 years or older who took vitamin D 700 IU plus calcium citrate 500 mg daily over a 3-year period had a 46% lower risk of falling. However, this combination did not decrease falls in males (14291).
• Fluorosis. Oral calcium has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Taking calcium orally, in combination with ascorbic acid (vitamin C) and vitamin D, seems to be effective for reducing excessive fluoride levels in children and improving symptoms of fluorosis in children aged 6-12 years (990).
• Heart failure. It is unclear if oral calcium in combination with vitamin D is beneficial for preventing heart failure. Details: Based on a secondary analysis of a large-scale clinical trial (Women's Health Initiative), taking calcium 1000 mg with vitamin D 400 IU daily does not reduce the risk of heart failure in the overall population or in individuals at high risk. However, in a subgroup of postmenopausal females without risk factors for heart failure, calcium and vitamin D supplementation might reduce the risk of developing heart failure by about 37% (97307).
• Lead toxicity. It is unclear if oral calcium is beneficial for reducing blood levels of lead. Details: Lead is mobilized along with calcium from bone during pregnancy and lactation, resulting in increased serum concentrations of lead. One clinical study suggests that calcium supplementation does not significantly decrease these elevated lead concentrations (1586). However, another clinical study suggests that taking calcium reduces blood lead levels by 11% when compared with placebo, with greatest effects observed in those with high baseline levels of lead (38957).
• Lyme disease. Although there is interest in using oral calcium for Lyme disease, there is insufficient reliable information about the clinical effects of calcium for this condition.
• Metabolic syndrome. It is unclear if oral calcium alone or with vitamin D is beneficial for metabolic syndrome prevention. Details: Population research has found that a higher intake of calcium from diet and supplements alone, or in combination with vitamin D, is associated with a lower risk of developing metabolic syndrome when compared with lower calcium intake (14265,16713).
• Nephrotic syndrome. It is unclear if oral calcium with vitamin D is beneficial for preventing nephrotic syndrome. Details: Clinical research shows that taking calcium 500-1000 mg daily for 3 months in combination with vitamin D3 60,000 IU daily or weekly for 4 weeks has no effect on bone mineral density or the risk of relapse in children with steroid-sensitive nephrotic syndrome (97355).
• Nonmelanoma skin cancer. It is unclear if oral calcium is beneficial for preventing keratinocyte carcinomas. Details: In middle aged and older adults recently diagnosed with a colorectal adenoma, clinical research shows that taking calcium 1200 mg daily as calcium carbonate for 3-5 years does not reduce the incidence of keratinocyte cancer when compared with placebo over a median of 8 years. A sub-group analysis shows that taking calcium alone or with vitamin D3 1000 IU daily reduced the risk of invasive cutaneous squamous cell carcinoma by a moderate amount, but had no effect on the risk of basal cell carcinoma (104622).
• Oral mucositis. When used in combination with fluoride treatments, a calcium phosphate mouth rinse seems to prevent and reduce mucositis-related pain in patients undergoing hematopoietic stem cell transplantation (HSCT). Details: A small clinical study in patients undergoing HSCT shows that using a particular mouth rinse (Caphosol, EUSA Pharma) containing calcium phosphate, in combination with fluoride treatments, reduces days of mucositis, the duration of pain, and the dose and days of morphine used when compared with placebo and fluoride treatment (38611).
• Ovarian cancer. It is unclear if oral calcium is beneficial for ovarian cancer prevention. Details: An older meta-analysis of 12 cohort studies found that dietary calcium intake is not associated with a reduced risk of ovarian cancer (38792). However, a more recent pooled analysis of 15 cohort and case-control studies has found that the highest intake of dietary or dairy calcium is associated with a 20% lower risk of ovarian cancer when compared to the lowest intake (97349).
• Postpartum depression. It is unclear if oral calcium is beneficial for reducing postpartum depression risk. Details: Preliminary clinical research shows that taking calcium 2 grams daily beginning at 11-21 weeks gestation reduces depression at 12 weeks postpartum when compared with placebo. However, no benefit is seen at 6 weeks postpartum (39447).
• Pregnancy-related leg cramps. It is unclear if oral calcium is beneficial for preventing leg cramps during pregnancy. Details: A small clinical study shows that taking calcium 1 gram twice daily (as a mixture of salts) for 2 weeks can reduce pregnancy-related leg cramps during the second half of pregnancy when compared with no treatment (2567).
• Prematurity. It is unclear if supplemental calcium is beneficial for the growth and development of preterm infants. Details: A small clinical study in preterm infants consuming human milk shows that supplementation with calcium 45 mg/kg daily and phosphorus 25 mg/kg daily does not affect infant weight, length, head circumference, or risk of osteopenia after 6 weeks when compared with human milk alone (113924). However, the duration and size of this study may have been too limited to detect any difference between groups.
• Preterm labor. It is unclear if oral calcium reduces the risk of preterm labor. Details: A meta-analysis of 10 clinical studies shows that taking calcium supplements during pregnancy does not reduce the risk of preterm labor when compared with placebo (113909). A separate meta-analysis of 7 clinical studies conducted in China, which evaluated the benefits of calcium carbonate 500-600 mg daily taken in conjunction with aspirin 50-75 mg daily during pregnancy, shows that this combination reduces the relative risk of preterm labor by 74% when compared with routine care (113913).
• Prostate cancer. It is unclear if oral calcium is beneficial for prostate cancer prevention. Details: Some clinical research shows that taking calcium 1200 mg daily might decrease the risk of developing prostate cancer (14133). However, some epidemiological research suggests that consuming very high doses of calcium, over 2000 mg daily, might actually increase the risk of developing prostate cancer (14134). Some epidemiological research also suggests that doses greater than 1500 mg daily increase the risk of poorly differentiated, clinically advanced, and fatal prostate cancer (14132). Consumption of dairy products has also been weakly linked to a modest increase in risk of prostate cancer (98894). However, contradictory research suggests that there is no association between dietary intake of calcium and overall risk of prostate cancer (14131,14132,104630).
• Stroke. It is unclear if oral calcium is beneficial for stroke prevention. Details: Some population research has found that increasing dietary calcium intake is associated with a decreased risk of ischemic stroke (4822,38678). However, other population research has found that increasing dietary calcium intake is not associated with a decreased risk of stroke (91350). One meta-analysis of high-quality randomized controlled trials shows that taking calcium for 2-7 years does not affect the risk of stroke when compared with control. However, the majority of the included research evaluated postmenopausal females, and it is unclear if this finding is applicable to other populations (107233).
• Vertigo. Oral calcium with vitamin D might reduce positional vertigo; the effect of calcium when used alone is unclear. Details: A large clinical study in adults with recurrent benign paroxysmal positional vertigo shows that taking calcium 500 mg and vitamin D 400 IU twice daily for one year reduces annual recurrence of vertigo by 27% when compared with no treatment. The number needed to treat to prevent vertigo was 3.7 (103681). It is unclear if this benefit is due to vitamin D, calcium, or the combination. More evidence is needed to rate calcium for these uses.

(Read more about CALCIUM)

LIKELY EFFECTIVE

• Chromium deficiency. Oral or parenteral chromium is effective for the treatment and prevention of chromium deficiency. Details: Chromium is effective for preventing and treating symptoms of chromium deficiency, including hyperglycemia, glycosuria, sudden weight loss, peripheral neuropathy, and confusion (7135).

POSSIBLY EFFECTIVE

• Diabetes. Oral chromium seems to be modestly beneficial for improving glycemic control in diabetes, especially when used in doses greater than 200 mcg daily and in patients with poorly controlled diabetes. It is unclear if chromium helps to prevent the development of diabetes. Details: Epidemiological research has found that lower toenail chromium levels are associated with an increased risk of diabetes and cardiovascular disease (11908). In 2005, the US Food and Drug Administration (FDA) allowed a qualified health claim stating that chromium picolinate may reduce the risk of type 2 diabetes. However, the FDA has determined that any relationship between chromium picolinate and type 2 diabetes is highly uncertain and is based on limited scientific evidence (102362). Research on the use of chromium for the treatment of type 2 diabetes is conflicting but seems to show modest benefit in some patients. Several clinical studies, most including fewer than 80 patients with type 2 diabetes, show that taking chromium decreases fasting blood glucose, postprandial glucose, insulin, and glycated hemoglobin (HbA1c) levels and increases insulin sensitivity (6867,7137,12390,14440,15169,42628,42638,95097,103745). However, other small clinical studies show that chromium is no better than placebo for improving most glycemic indices in patients with diabetes (7060,14325,42679,42707,90059,103746,103749). Some of these studies may not have been adequately powered and some had a high risk of bias. Furthermore, these studies had high heterogeneity related to study population and size, chromium supplementation duration, formulation, and dose, and accepted standards of diabetes care. Multiple meta-analyses pooling results of these small clinical trials also show mixed results (90055,90063,95098,105026,110610,111420). The most recent of the aforementioned meta-analyses show that chromium picolinate lowers HbA1c by about 0.6%, with conflicting findings related to fasting blood glucose and measures of insulin resistance (110610,111420). It is unclear if chromium yeast, chromium dinicocysteinate, or chromium with biotin or other natural ingredients are beneficial. Chromium seems to be most beneficial in doses of greater than 200 mcg taken for 12 weeks or longer, and in patients with poorly controlled diabetes with a baseline HbA1c of 8% or greater (90063,105026). There is also speculation that chromium might primarily benefit patients with low chromium levels; however, there has not been an analysis specifically evaluating this population (6867,7058,13725,14325,95098). Some research suggests that chromium might also modestly improve lipid levels in patients with type 2 diabetes (1934,6867,95098). A meta-analysis of clinical trials in patients with type 2 diabetes shows that taking chromium 42-1000 mcg daily for 5-26 weeks decreases triglyceride levels by 7 mg/dL and increases high-density lipoprotein cholesterol levels by 2 mg/dL when compared with control. Taking chromium did not affect low-density lipoprotein cholesterol levels. However, the validity of these results is limited by high heterogeneity (110605). Another meta-analysis failed to demonstrate any effects of chromium on lipid levels (110610). Research on chromium's effect on blood pressure in patients with type 2 diabetes is mixed. A meta-analysis of clinical trials in patients with type 2 diabetes shows that taking chromium 200-1000 mcg daily for 8-25 weeks lowers diastolic blood pressure by 2 mmHg, but does not improve systolic blood pressure or body mass index, when compared with placebo (110607). Preliminary clinical research shows that chromium picolinate might improve metabolic parameters in patients with other forms of diabetes as well. This includes those with type 1 diabetes (1935), diabetes secondary to corticosteroid use (5039,42829), and gestational diabetes (42817).

POSSIBLY INEFFECTIVE

• Hypertension. Meta-analyses of small clinical trials suggest that oral chromium does not lower blood pressure by a clinically meaningful amount. Details: A meta-analysis of randomized clinical trials in adults with different metabolic disorders shows that taking chromium 42-1000 mcg daily for 12-24 weeks does not lower systolic or diastolic blood pressure when compared with placebo (110609). A meta-analysis of randomized clinical trials in adults with different chronic disorders shows that taking chromium 42-1000 mcg daily for 4-25 weeks lowers systolic and diastolic blood pressure by 3 mmHg and 1 mmHg, respectively, when compared with placebo. However, the validity of this meta-analysis is limited by high heterogeneity (110604). Another meta-analysis of randomized clinical trials including patients with type 2 diabetes shows that taking chromium 200-1000 mcg daily for 8-25 weeks lowers diastolic blood pressure by 2 mmHg, but not systolic blood pressure, when compared with placebo (110607). In addition, the validity of these results is limited by inclusion of patients with and without hypertension at baseline (110604,110607,110609).
• Impaired glucose tolerance (Prediabetes). Oral chromium does not seem to improve glycemic indices in patients with prediabetes. Details: Some clinical research shows that adults with impaired glucose tolerance do not have improved glycemic parameters or insulin sensitivity after taking chromium picolinate 500-1000 mcg daily for up to 6 months when compared with placebo (13053,42670). Likewise, a small clinical study in elderly patients with impaired glucose tolerance shows that chromium supplements do not improve glucose tolerance or triglyceride or cholesterol levels when compared with placebo (13722). Finally, a preliminary clinical study in overweight or obese adults with prediabetes shows that taking two capsules of a combination product containing chromium, cinnamon, and carnosine (Glycabiane, PiLeJe) daily for 4 months decreases fasting plasma glucose by approximately 4 mg/dL when compared with placebo, but does not improve fasting plasma insulin, measures of insulin sensitivity or resistance, or glycated hemoglobin (HbA1C) (94234). The small effect on fasting plasma glucose is clinically insignificant and may be due to the other ingredients in this product.
• Schizophrenia. Oral chromium does not seem to improve psychological measures in patients with schizophrenia. Details: Clinical research in patients with schizophrenia shows that taking chromium polynicotinate 400 mcg daily for 3 months does not affect weight or mental status when compared with placebo (42613).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Antiretroviral-induced insulin resistance. It is unclear if oral chromium is beneficial for preventing antiretroviral-induced insulin resistance. Details: Preliminary clinical research in patients with HIV treated with highly active antiretroviral therapy (HAART) shows that taking chromium nicotinate 200 mcg or chromium picolinate 1000 mcg daily for 8-16 weeks may help decrease insulin resistance and increase glucose disposal when compared to baseline (42630,42662). The validity of this finding is limited by the lack of a control group.
• Athletic performance. It is unclear if chromium enhances athletic performance, although some research suggests that it may improve body composition when used in conjunction with exercise. Details: One large clinical study shows taking chromium 400 mcg daily, in conjunction with resistance training, can increase weight loss, body fat loss, and lean body mass when compared with placebo in conjunction with resistance training (6868). However, other, very small clinical studies show that adding chromium picolinate or chromium chloride 177-400 mcg daily to a weight-training program does not improve body composition when compared with weight-training alone (6860,6861,6862,42747). These studies may not have been adequately powered to detect a difference in outcomes.
• Atypical depression. It is unclear if oral chromium is beneficial in patients with atypical depression. Details: Preliminary clinical research in patients with atypical depression shows that taking chromium picolinate 400 mcg daily for 2 weeks followed by 600 mcg daily for an additional 6 weeks improves response and remission rates when compared with placebo (10309). However, other clinical research shows that taking elemental chromium 400 mcg in the form of chromium picolinate daily for 2 weeks followed by 600 mcg daily for an additional 6 weeks does not improve most symptoms of atypical depression, although appetite and sexual drive may improve, when compared with placebo (42600).
• Beta blocker-induced dyslipidemia. It is unclear if oral chromium is beneficial in patients with dyslipidemia due to beta-blocker use. Details: One small clinical study in patients who take beta-blockers shows that taking glucose tolerance factor (GTF)-chromium 600 mcg daily for 2 months increases high-density lipoprotein (HDL) cholesterol levels by 16%, but does not affect other lipid parameters, when compared with placebo (5040).
• Binge eating disorder. It is unclear if oral chromium is beneficial in patients with binge eating disorder. Details: One small clinical study in adults with overweight and binge eating disorder shows that taking chromium picolinate 600 or 1000 mcg daily for 6 months does not affect binge eating frequency, body weight, or depressive symptoms when compared with placebo (90057).
• Bipolar disorder. It is unclear if oral chromium is beneficial in patients with treatment-resistant bipolar disorder. Details: Preliminary clinical research in patients with treatment-resistant, rapid-cycling bipolar disorder shows that taking chromium chloride (Hypo-A Chrom, Hypo-A GmbH) 600-800 mcg daily for up to 2 years can decrease the frequency of affective episodes by approximately three episodes annually when compared to baseline (42618). The validity of this finding is limited by the lack of a control group.
• Cognitive impairment. It is unclear if oral chromium prevents or treats cognitive impairment. Details: Some clinical research shows that taking chromium picolinate standardized to contain elemental chromium 1000 mcg daily for 12 weeks does not improve memory or depression in elderly patients with mild cognitive impairment when compared with placebo. However, results from neuroimaging scans suggest that chromium increases the activity of certain regions of the brain during memory tasks when compared with placebo (42666).
• Hyperlipidemia. Small clinical studies suggest that oral chromium may modestly reduce lipid levels in patients with hyperlipidemia. Details: One small clinical study in patients with atherosclerotic disease shows that taking chromium 250 mcg as chromium chloride daily for 7-16 months decreases triglycerides and increases high-density lipoprotein (HDL) cholesterol, but not other lipid parameters, when compared with placebo (7060). Other small clinical studies in adults with hyperlipidemia show that taking chromium picolinate 200 mcg daily for 6 weeks, chromium polynicotinate 200 mcg twice daily, or brewer's yeast containing 48 mcg elemental chromium daily for 6-8 weeks decrease total and low-density lipoprotein (LDL) cholesterol when compared to baseline (37178,42585,42710). The validity of this finding is limited by the lack of comparison with a control group. A meta-analysis of small heterogeneous clinical studies in patients mostly without hyperlipidemia shows that taking chromium does not affect lipid levels when compared with placebo (105029). A meta-analysis of randomized clinical trials including patients with type 2 diabetes shows that taking chromium 42-1000 mcg daily for 5-26 weeks modestly improves triglyceride and HDL cholesterol levels, but not LDL cholesterol levels, when compared with control. However, the validity of these results is limited by high heterogeneity and inclusion of patients with and without hyperlipidemia (110605). In addition, some meta-analyses have failed to demonstrate any effects of chromium on lipid levels in adults with diabetes (110610). Limited research has tested high-dose chromium in children. One small clinical study in children with hypercholesterolemia shows that taking chromium polynicotinate 400-600 mcg with glucomannan 1000-1500 mg twice daily for 8 weeks reduces total and LDL cholesterol when compared to baseline (90061). It is unclear if this effect is due to chromium, glucomannan, or the combination.
• Hypoglycemia. It is unclear if oral chromium helps to reverse or prevent hypoglycemia. Details: One very small clinical study in patients with reactive hypoglycemia shows that taking chromium chloride 200 mcg daily for 3 months increases blood glucose levels and improves insulin binding and hypoglycemic symptoms following an oral glucose load (6859). Another small clinical study in patients with symptomatic hypoglycemia shows that taking chromium yeast (Biochrome, Pharma-Nord) 125 mcg daily for 3 months improves symptoms, including chilliness, trembling, and disorientation, when compared with baseline (42711). The validity of this finding is limited by the lack of a control group.
• Metabolic syndrome. It is unclear if oral chromium is beneficial in patients with metabolic syndrome. Details: One small clinical study in patients with metabolic syndrome shows that taking a particular chromium picolinate product (Chromax, Nutrition 21) 500 mcg twice daily for 16 weeks does not affect weight, waist circumference, insulin sensitivity, glycated hemoglobin (HbA1C), or lipid levels when compared with placebo (42654).
• Myocardial infarction (MI). It is unclear if oral chromium helps to prevent MI. Details: Epidemiological research has found that low toenail chromium concentrations are associated with an increased risk of MI (13728). However, toenail chromium concentrations might not be a reliable predictor of body stores of chromium. There is also no reliable research showing that chromium supplements can prevent MI.
• Nonalcoholic fatty liver disease (NAFLD). It is unclear if oral chromium slows NAFLD progression. Details: One small clinical study in patients with NAFLD shows that taking chromium picolinate 200 mcg two times daily after meals for 12 weeks does not affect liver enzyme levels or body weight when compared with placebo (105027).
• Obesity. Although some research suggests that oral chromium may increase weight loss, this increase in weight loss is not likely to be considered clinically relevant. Details: Meta-analyses of clinical studies in adults with overweight or obesity show that taking chromium picolinate 200-1000 mcg daily for 12-16 weeks might result in a cumulative weight loss of about 0.5-1 kg when compared with placebo (90062,90065). However, this small reduction in weight is unlikely to be considered clinically significant. Additionally, small clinical studies in healthy adults and children with overweight or obesity show that taking oral chromium 200-1000 mcg daily for 6-24 weeks does not reduce weight when compared with control (6860,13727,17224,42680). Some of these studies may not have been adequately powered to detect a smaller effect. A meta-analysis of randomized clinical trials among adults with type 2 diabetes shows that taking chromium 200-1000 mcg daily for 8-25 weeks does not lower body mass index when compared with placebo. However, the validity of these results is limited by inclusion of patients with and without obesity at baseline (110607).
• Polycystic ovary syndrome (PCOS). It is unclear if oral chromium improves symptoms of PCOS. Details: One small clinical study in patients with PCOS shows that taking chromium picolinate 1000 mcg daily for 6 months along with diet and exercise counseling decreases body mass index and improves rates of ovulation and regular menstruation when compared with placebo (95094). Also, some clinical research shows that taking chromium picolinate (21st Century HealthCare, Inc. or Nature Made) 200 mcg daily for 8 weeks increases insulin sensitivity when compared with placebo (95095,98687). However, other preliminary clinical research shows that taking chromium picolinate 200 mcg daily for 4 months does not affect insulin sensitivity or improve ovulation rates (42603). Although chromium picolinate at doses of less than 1000 mcg might have very small effects on fasting glucose, these doses do not seem to have clinically beneficial effects on fasting glucose, pregnancy rate, or testosterone levels (95094,95095,98687). A lower dose of chromium has also been studied in combination with carnitine. One small clinical study in adults with overweight and PCOS shows that taking chromium picolinate 200 mcg daily with carnitine 1000 mg daily for 12 weeks modestly reduces fasting blood glucose, insulin resistance, and body weight, and slightly increases insulin sensitivity, when compared with placebo (103747). However, it is unclear if this benefit is clinically significant. Additionally, it is unclear if these effects are due to chromium, carnitine, or the combination. Carnitine has demonstrated clinical benefit when used alone in PCOS.
• Turner syndrome. It is unclear if oral chromium is beneficial in patients with this condition. Details: A small clinical study shows that taking brewer's yeast 30 grams containing chromium 50 mcg daily for 8 weeks might improve abnormalities in glucose and lipid metabolism when compared with baseline in patients with Turner syndrome, a genetic disorder that has a high incidence of diabetes (13729). The validity of this finding is limited by the lack of a comparator group. More evidence is needed to rate chromium for these uses.

(Read more about CHROMIUM)

LIKELY EFFECTIVE

• Human papillomavirus (HPV). A specific green tea extract ointment (Polyphenon E ointment 15%) is approved by the US Food and Drug Administration (FDA) for treating external genital warts caused by HPV. Details: A specific green tea extract ointment (Veregen, Bradley Pharmaceuticals; Polyphenon E ointment 15%, MediGene AG) providing 150 mg of sinecatechins per gram of ointment, applied three times daily to external warts, completely clears external genital and perianal warts in 24% to 60% of patients after 10-16 weeks of treatment (15067,36438,36442,53777,53907,54018). This green tea extract is an FDA-approved prescription product (15067).

POSSIBLY EFFECTIVE

• Cardiovascular disease (CVD). Drinking green tea seems to reduce the risk of CVD and CVD-related mortality. Details: Large-scale population research in Japan suggests that consuming at least 3-5 cups of green tea daily is associated with a reduced risk of cardiovascular mortality when compared with drinking less than 1 cup daily. This association appears to be primarily related to a decrease in risk for cerebral infarction and heart disease. This association appears to be stronger in females than in males (14498,53789,100202). Population research also suggests that drinking green tea is associated with a reduced risk of CVD. One meta-analysis suggests that drinking green tea is associated with a 28% reduced risk of CAD (54017). Another meta-analysis suggests that consuming small to moderate amounts of green tea, 1-5 cups or 300 to 1500 mL daily, is associated with an 8% to 16% reduced risk of coronary heart disease over 5 to 13 years when compared with consuming no green tea (111017). One meta-analysis suggests that a 1 cup increase in green tea consumption is associated with a 5% reduced risk of CVD mortality and a 3% reduced risk of CVD events (102728). When compared with drinking less than 1 cup of green tea daily, epidemiological research in a population at high risk of coronary artery disease (CAD) suggests that drinking more than 3 cups of green tea daily is associated with a 46% reduced odds of having CAD, especially severe CAD, as determined by a coronary angiography (104588). A sub-group analysis suggests that these odds only occurred in individuals consuming fruits more than 4 times weekly and not in individuals consuming fruits less often (104588). However, some population research suggests that any association seems to be greater for males than females (53691). Other population studies suggest that general tea consumption might protect against ischemic heart disease or death from CVD; however, many of the tea drinkers in some of these studies consumed black tea rather than green tea (8119,8120,8121,102728).
• Endometrial cancer. Drinking green tea seems to be beneficial for endometrial cancer prevention. Details: Meta-analyses of epidemiological research have found that people who drink green tea often, usually more than once daily, have a 21% to 23% reduced risk of developing endometrial cancer when compared with those who never or rarely drink green tea (53919,92409,102716). One of these meta-analyses also found that increasing green tea intake by one cup per day is associated with an 11% reduced risk of developing endometrial cancer (92409).
• Hyperlipidemia. Oral green tea seems to reduce levels of low-density lipoprotein (LDL) cholesterol by a small amount. Details: Clinical research and a meta-analysis of clinical research in people with or without hyperlipidemia shows that consuming green tea or green tea extract containing 150-2500 mg catechins daily for up to 24 weeks reduces total cholesterol by about 5-24 mg/dL and LDL cholesterol by about 2-25 mg/dL when compared with control (11308,54038,54048,90146,90161,97135,104605). There is also preliminary evidence that taking a green tea extract containing catechins 676 mg daily for 12 weeks reduces oxidation of LDL cholesterol when compared with placebo, which might lead to reduced damage to the vascular endothelium and reduced arteriosclerosis (98458). Epidemiological research has found that higher consumption of green tea, especially 10 cups daily or more, is associated with improved serum lipids in males, but not females (6403,97134).
• Ovarian cancer. Drinking green tea seems to be beneficial for ovarian cancer prevention. Details: Consuming tea, including green tea or black tea, appears to significantly lower the risk of developing ovarian cancer when compared with never or seldom consuming tea (9228,13208,90144,102716). One meta-analysis of population research suggests that the highest intake of green tea is associated with a 36% reduced risk of ovarian cancer when compared with the lowest intake (102716). Also, one prospective population study found that those who consume 2 or more cups of tea daily have a 46% lower risk of ovarian cancer when compared with those who don't regularly consume tea (13208). There also appears to be a trend that suggests higher consumption of tea or longer duration of use further reduces the risk of ovarian cancer (9228,13208). However, green tea does not appear to prevent ovarian cancer recurrence. Preliminary clinical research shows that drinking 500 mL of double-brewed green tea (DBGT), prepared with 35 grams/L of tea leaves standardized to contain approximately 640 mg/L of EGCG, daily for up to 18 months does not prevent cancer recurrence in adults with a history of advanced stage serous or endometrioid ovarian cancer (90175).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Acne. Topical green tea might reduce acne lesions by a small amount. It is unclear if oral green tea is beneficial for acne. Details: A meta-analysis of preliminary clinical research shows that topical application of green tea extract reduces the number of inflammatory and non-inflammatory lesions by a small amount (104609). In one small study, applying a solution containing the green tea constituent epigallocathechin-3-gallate (EGCG) 1% or 5% twice daily for 8 weeks was used (54074). However, oral green tea extract had limited or no effect in one study included in a meta-analysis (104609). Higher quality studies are needed to confirm this finding.
• Age-related cognitive decline. It is unclear if oral green tea is beneficial for cognitive decline associated with age. Details: In elderly individuals living in the community, clinical research shows that taking matcha green tea powder (Yabukita, Kyoeiseicha Co., Ltd.) 3 grams daily for 12 weeks does not improve overall measures of cognitive function when compared with placebo. However, a sub-group analysis in females found a small improvement in language, but not other measures, including memory, impulsivity, and attention (104602). Other clinical research in middle aged and older adults shows that taking green tea extract (Thea-Flan 90S, ITO EN Ltd.) providing catechins 336.4 mg daily for 12 weeks does not improve most measures of cognitive function, although there was a small effect on one measure of working memory. In addition, a single dose has a small effect on errors during an attention task (104603).
• Amyloidosis. It is unclear if oral green tea is beneficial for amyloidosis. Details: Preliminary clinical research in patients with cardiac transthyretin amyloidosis shows that drinking green tea (Green Darjeeling, FTGFOP1, Teekampagne Projektwerkstatt GmbH) 1.5-2 liters standardized to contain epigallocatechin-3-gallate (EGCG) 340 mg/L and/or taking specific capsules (Praevent-loges, Dr. Loges + Co. GmbH) containing 300 mg green tea extract standardized to contain EGCG 75 mg/capsule for 12 months protects against an increase in left ventricular wall thickness and left ventricular myocardial mass (54064).
• Anxiety. Although there has been interest in using oral green tea for anxiety, there is insufficient reliable information about the clinical effects of green tea for this condition.
• Athletic performance. The evidence on the effects of green tea constituents for athletic performance is conflicting. Details: Some preliminary clinical research shows that taking green tea extract containing up to 572.8 mg of catechins as a beverage does not improve respiration efficiency, maximal oxygen uptake, or time trial performance in individuals undergoing endurance training when compared with beverages without catechins (53987,53991). However, other preliminary research shows that taking specific pills (Teavigo, Healthy Origins) containing epigallocatechin-3-gallate (EGCG) 135 mg/pill, taken three times daily with meals for a total dose of seven pills, improves maximal oxygen uptake but not maximum work rate or respiration efficiency, in healthy adults when compared with placebo (53944). Also, a small study in untrained adults shows that taking a single dose of green tea polyphenols 640 mg, 90 minutes before exercise, increases maximal oxygen uptake. However, the effect on athletic performance was not determined (104606).
• Beta-thalassemia. It is unclear if oral green tea is beneficial for reducing iron accumulation in beta-thalassemia. Details: A small clinical trial shows that taking green tea 3 cups daily after meals for 12 months, in addition to usual treatment with blood transfusions and deferasirox, an iron chelator, reduces levels of liver iron and serum ferritin by moderate amounts when compared with usual treatment alone. Hemoglobin values did not differ between groups. Each green tea bag contained 2 grams green tea (Lipton, Unilever Gulf) (104601).
• Bladder cancer. It is unclear if drinking green tea is beneficial for bladder cancer prevention. Details: Some epidemiological evidence suggests that drinking green tea is associated with a reduced risk of bladder cancer (1458,1459,90179). However, conflicting evidence exists. A meta-analysis of some epidemiological evidence suggests that drinking green tea is not associated with a reduced risk of bladder cancer (54077,90166,102716).
• Breast cancer. Evidence evaluating the association between green tea intake and breast cancer risk is inconsistent; any association may be dependent on genotype and menopausal status. Details: Meta-analyses of cohort and case-control studies have found that green tea intake is not associated with a reduced risk of breast cancer (98460,102716). However, some individual population studies suggests that green tea intake is associated with a reduced odds of developing breast cancer in Asian-American (14427,53866), but not Asian (13189,14426,90181), populations. Any protective effect of green tea on breast cancer risk might depend on patient genotype or menopausal status. Green tea consumption does not seem to lower breast cancer risk in Asian females with low-activity angiotensin-converting enzyme (ACE) genotype, although it does seem to decrease breast cancer risk in Asian females with high-activity ACE genotype (14430). Similarly, Asian-American females who drink green tea seem to have a lower breast cancer risk if they have low-activity catechol-O-methyltransferase (COMT) genotype. However, they do not seem to benefit if they do not have the low-activity COMT genotype (14431). Additionally, some observational research suggests that there is a link between green tea and modestly reduced breast cancer risk in pre-menopausal, but not postmenopausal, females (99788). Some research has evaluated the effect of green tea on breast cancer recurrence. Population research suggests that Asian females who have had stage I or II breast cancer who drink at least 3 cups of green tea daily seem to have reduced risk of breast cancer recurrence (3926,13189,54112). However, drinking green tea does not seem to significantly reduce the risk of recurrence of later-stage breast cancer. In April 2012, the US Food and Drug Administration (FDA) determined that it would allow a qualified health claim stating that consuming green tea may reduce the risk of breast cancer, although the FDA has concluded that there is very little scientific evidence to support this claim (102106).
• Cervical cancer. It is unclear if oral green tea is beneficial for cervical cancer. Details: Clinical research in adults with persistent high-risk HPV (HR HPV) infection and concomitant low-grade cervical intraepithelial neoplasia shows that taking a specific green tea extract (Polyphenon E), four capsules standardized to contain epigallocatechin-3-gallate (EGCG) 200 mg/capsule, once daily for 4 months does not affect HR HPV-positive status or histological outcomes when compared with placebo (90145).
• Cervical dysplasia. It is unclear if topical green tea is beneficial for cervical dysplasia. Details: Preliminary clinical research shows that applying a specific ointment (Polyphenon E ointment 15%, MediGene AG) containing epigallocatechin-3-gallate (EGCG) to human papilloma virus (HPV)-infected cervical lesions twice weekly and/or taking a specific green tea extract (Polyphenon E) 200 mg daily containing EGCG by mouth for 8-12 weeks can improve lesion appearance when compared with control (11310).
• Chronic fatigue syndrome (CFS). Although there has been interest in using oral green tea for CFS, there is insufficient reliable information about the clinical effects of green tea for this condition.
• Chronic obstructive pulmonary disease (COPD). It is unclear if drinking green tea reduces the risk of COPD. Details: One prospective, observational study in older adults has found that consumption of at least 3 cups daily of tea, including green tea, oolong tea, and black tea, is associated with a 23% reduction in COPD prevalence and a 65% reduced risk of developing COPD in models adjusted for potential confounders when compared with the lowest tea consumption (107201). However, green tea was only consumed by about 19% of the population included in this study and consumption of green tea itself was not associated with a reduced risk of COPD.
• Cognitive function. It is unclear if oral green tea improves cognitive function in healthy adults. Details: A small clinical study in adults ages 50-69 years shows that taking matcha powder (Hojin no shiro, Ito En, Ltd.) 9 capsules daily for 12 weeks, providing 170 mg total catechins daily, modestly improves some measures of attention and work performance when compared with taking placebo or caffeine. However, there was no effect on other measures of these outcomes, or on verbal memory tasks, visual information processing, working memory, motor function, or facial expression recognition (107168). Another small clinical study shows that taking a single dose of the green tea constituent, epigallocathechin-3-gallate (EGCG), 135 or 270 mg does not seem to improve mood or cognitive performance in healthy adults (54059). Green tea has also been evaluated in combination with other ingredients. A small clinical study in healthy adults shows that consuming a multi-ingredient beverage containing green tea powder 50 mg, elderberry extract, carob extract, and guarana seed extract improves some measures of cognitive function such as rapid visual information processing and multitasking, but not others, 120 minutes later when compared with placebo (113940). It is unclear if this effect is due to green tea, other ingredients, or the combination.
• Cognitive impairment. It is unclear if oral green tea is beneficial for the prevention or treatment of mild cognitive impairment in elderly adults. Details: Some population research in elderly individuals has found that drinking green tea at least once per week is associated with a 53% reduced incidence of dementia or mild cognitive impairment when compared to not consuming green tea (104598). In addition, drinking at least two cups of green tea daily was associated with a 54% lower prevalence of cognitive impairment (104611). Some clinical research shows that taking two capsules of a specific combination product containing green tea extract 360 mg/capsule and L-theanine 60 mg/capsule (LGNC-07, LG Household & Health Care, Ltd) twice daily after meals for 16 weeks improves memory and attention in patients with mild cognitive impairment when compared with placebo (54019).
• Colorectal adenoma. It is unclear if oral green tea extract is beneficial for reducing colorectal adenoma recurrence. Details: A large clinical trial in patients with previously removed colorectal adenomas shows that taking green tea extract (Dr. Loges + Co. GmbH) standardized to epigallocatechin gallate (EGCG) 150 mg twice daily for 3 years does not affect the risk of developing new metachronous adenomas when compared with taking placebo (111020). However, a sub-group analysis shows that taking green tea extract results in a 10% absolute reduction in risk of adenoma formation in males, but not females (111020). Also, preliminary clinical research in patients with previously removed colorectal adenomas shows that taking green tea extract 1.5 grams daily for 12 months reduces the incidence of metachronous adenomas when compared with placebo (53816).
• Colorectal cancer. It is unclear if oral green tea is beneficial for colorectal cancer prevention. Details: Although evidence from individual population studies is mixed (9222,9223,14498,90176,90178,90181,102718), meta-analyses of population research suggest that a high intake of green tea is associated with a reduced risk of colorectal cancer (36416,102716). The highest intake of green tea is associated with a 16% reduced risk when compared with the lowest; however, the benefit appears to be specific to colon cancer, not rectal cancer (102716). When subdivided according to gender, evidence from case-control research suggests that green tea is associated with a reduced risk of colon and rectal cancer for females (54096).
• Common cold. It is unclear if oral green tea is beneficial for the common cold. Details: Preliminary clinical research shows that taking two capsules of a specific formulation (ImmuneGuard, Nutraceutical Holdings LLC) containing L-theanine (Suntheanine, Taiyo International) plus epigallocatechin gallate (Sunphenon, Taiyo International) twice daily for 3 months reduces cold or flu symptoms and duration of symptoms when compared with placebo in healthy adults (53754).
• Crohn disease. Although there has been interest in using oral green tea for Crohn disease, there is insufficient reliable information about the clinical effects of green tea for this condition.
• Dementia. It is unclear if drinking green tea is beneficial for dementia prevention. Details: A meta-analysis of observational studies in over 20,000 adults suggests that the risk of any cognitive deficit (including mild cognitive impairment and dementia) is associated with a 6% reduction per cup of green tea consumed daily (107829). Some population research in elderly individuals suggests that drinking green tea at least once per week is associated with a 53% reduced incidence of dementia or mild cognitive impairment when compared to not consuming green tea (104598). Other population research in adults ages 40-74 years suggests that drinking at least 600 mL of green tea daily is not associated with a reduced risk of developing dementia when compared with drinking less than 60 mL daily. However, there is a modest reduction in dementia risk specifically in individuals ages 60-69 years (107164). A prospective, observational study suggests that consumption of tea, including both green and black tea, of at least 4 cups, in conjunction with 0.5-1 cups of coffee, daily is associated with a 30% reduced risk of dementia when compared with not drinking tea or coffee. Also, drinking 2-3 cups daily of both tea and coffee is associated with a 28% reduced risk of dementia when compared with not drinking tea and coffee (107204). Any association between drinking green tea specifically and developing dementia cannot be determined from this study.
• Dental plaque. It is unclear if oral or topical green tea is beneficial for reducing dental plaque. Details: A meta-analysis of clinical research shows that use of oral or topical products containing green tea modestly reduces dental plaque when compared with control products, including triclosan toothpaste, placebo, and chlorhexidine rinse. However, a sub-group analysis shows that a green tea rinse is no more effective than a chlorhexidine rinse. Green tea products in these studies included mouth rinse, paste, tea, capsules, and strips (107156). Many of these studies are limited by a lack of clear blinding. A more recent clinical study in children ages 10-14 years with plaque and gingivitis shows that using a mouthwash containing green tea extract 5% twice daily, alone or at half strength with ginger extract, for 30 days reduces plaque and gingivitis severity. The mouthwash containing the combination of green tea and ginger extract was most effective, and the green tea extract alone was at least as effective as chlorhexidine (107163).
• Depression. It is unclear if drinking green tea is beneficial for depression prevention. Details: Epidemiological research suggests that consuming green tea is associated with a reduced prevalence of depression and depressive symptoms. In Japanese adults, drinking four or more cups of green tea daily is associated with a 44% to 51% lower prevalence of mild to severe depression when compared to consuming one cup or less daily (90160,90163). A meta-analysis suggests that the highest green tea consumption is associated with a 34% reduced risk of depressive symptoms when compared with the lowest (111024). Other research in a general population of Chinese adults suggests that consuming at least 1 cup of green tea daily is associated with a 22% decreased risk of depressive symptoms over 2 years when compared with almost never consuming green tea. However, there is no association between depressive symptoms and less frequent green tea consumption in this population (111023).
• Diabetes. It is unclear if drinking green tea or taking green tea extract is beneficial for the prevention of diabetes or the improvement of glycemic control. Details: Epidemiological research has found that Japanese adults who consume 6 or more cups of green tea daily have a 33% lower risk of developing type 2 diabetes when compared to those who consume one cup or less daily. The risk reduction appears to be more pronounced in females when compared with males (14313). Also, epidemiological research has found that Chinese adults who consume at least one cup of green tea per week have a 59% to 77% lower risk of impaired fasting glucose when compared to those who consume less than one cup per week (90149). Other epidemiological research has found that consumption of any amount of green tea daily by Chinese adults is associated with an 8% reduced risk of developing type 2 diabetes when compared with never drinking green tea (107165). In contrast, some epidemiological research in Chinese adults has found that green tea consumption is associated with a 20% increased risk of developing type 2 diabetes when compared with non-green tea drinkers. A dose-response relationship was found for both the amount and duration of tea consumed (107170). Also, clinical research in patients with prediabetes shows that drinking one cup of green tea three times daily for 14 weeks does not improve fasting blood glucose or glycated hemoglobin (HbA1c) when compared to control (90174). There is inconsistent evidence regarding the effects of green tea in patients with type 2 diabetes. Epidemiological research suggests that drinking at least 4 cups of green tea daily is associated with a 40% reduction in mortality risk when compared to not drinking green tea (104589). Other epidemiological research in patients with type 2 diabetes has found that consumption of any amount of green tea daily is associated with a 10% reduction in mortality risk when compared to never drinking green tea. However, there was no association between green tea intake and the incidence of developing macrovascular or microvascular complications (107165). Meta-analyses of clinical research show that green tea extract and green tea catechins reduce fasting blood glucose when compared to control when patients with type 2 diabetes, borderline diabetes, or normal blood glucose status are evaluated together (90154,90187). However, a meta-analysis of up to 15 mainly small clinical trials involving patients with type 2 diabetes shows that taking green tea does not affect fasting blood glucose or insulin or improve insulin resistance or glucose control when compared with placebo. Most included studies used green tea or its extract in doses of 400-10,000 mg daily for 8-16 weeks (104604). Also, clinical research shows that taking green tea extract daily for up to 16 weeks does not improve blood glucose, HbA1c, or insulin when compared with placebo in patients with type 2 diabetes or borderline diabetes (37678,37781,54035). Some research has evaluated the effect of green tea on other outcomes in patients with type 2 diabetes. One meta-analysis shows that taking green tea extract modestly reduces fasting triglyceride levels when compared with control. This benefit was seen with doses of at least 800 mg daily taken for longer than 8 weeks. This dose and duration reduces levels of total cholesterol, but not low-density lipoprotein (LDL) or high-density lipoprotein (HDL) cholesterol levels (102715). Another meta-analysis shows that taking green tea modestly reduces body weight, body mass index (BM), and body fat. A sub-analysis shows that these benefits occur in studies lasting more than 8 weeks, using doses of up to 800 mg daily, and in patients who were overweight. There was no effect on waist circumference. Most patients included in the analysis were overweight or had obesity (104610).
• Diabetic neuropathy. It is unclear if oral green tea is beneficial for improving diabetic neuropathy symptoms. Details: Clinical research in patients with mild-to-moderate diabetic peripheral neuropathy shows that taking decaffeinated green tea extract 500 mg three times daily for 16 weeks modestly reduces neural pain and dysfunction, as well as overall symptom severity, when compared with placebo (107159).
• Down syndrome. It is unclear if oral green tea is able to alter facial morphology in children with Down syndrome.
• Down syndrome. There was no effect in children aged 4-18 years (107167). This study is limited by its observational design. The dosage, time of onset, and duration of treatment differed between individuals.
• Dry eye. It is unclear if oral green tea is beneficial for improving dry eye symptoms. Details: In patients with mild to moderate dry eye and meibomian gland dysfunction, preliminary clinical research shows that applying green tea extract into the eyes three times daily for one month, in addition to artificial tears three times daily, improves symptoms of dry eye. Symptoms of itching, burning, foreign body sensation, and redness were improved by a moderate amount over artificial tears alone (104612).
• Dysmenorrhea. It is unclear if drinking green tea is beneficial for preventing dysmenorrhea symptoms. Details: Population research has found that drinking green tea is associated with a 37% reduced odds of experiencing dysmenorrhea and a 58% reduced odds of having moderate-to-severe dysmenorrhea when compared with not drinking green tea (102729).
• Esophageal cancer. It is unclear if drinking green tea is beneficial for preventing esophageal cancer; the available research is conflicting. Details: Although some epidemiological evidence and observational studies have found that drinking green tea is associated with a reduced risk of esophageal cancer, most meta-analyses do not support this finding in a mixed group of adults (1457,36542,90169,90185,90186,102004,102716,107154). Meta-analyses of epidemiological studies suggest that drinking green tea is associated with a 54% reduction in the risk of esophageal cancer, or a 21% reduced odds per cup of green tea consumed daily, only in females (90169,90185,102004,107154). Also, some epidemiological research found that drinking green tea that is very hot is associated with an increased risk of esophageal cancer (53828). In addition, drinking decaffeinated green tea 5 mg daily for 12 months does not seem to be an effective treatment for patients diagnosed with esophageal precancerous lesions (53702).
• Fractures. It is unclear if drinking green tea reduces fracture risk. Details: Population research has found that consumption of green tea is associated with a 12% lower risk of any fracture and 20% lower risk of hip fracture when compared with no tea consumption (99800).
• Gastric cancer. Evidence evaluating an association between green tea consumption and gastric cancer risk is conflicting. Details: Most meta-analyses of epidemiological studies suggest that green tea consumption is not associated with gastric cancer risk (53767,53813,90181,102716). Although the most recent meta-analysis of epidemiological research suggests that drinking green tea regularly is associated with up to a 9% reduced risk of gastric cancer when compared with non-regular consumption, sub-analyses suggest that there is no association between gastric cancer and intake of specific amounts of green tea up to at least 3 cups daily (111025). Also, other population research suggests that drinking 10 or more cups of green tea daily is associated with a reduced risk of gastric cancer (8903,9222,9225,9226,9227), while consuming less than 10 cups daily is not consistently associated with a reduced risk (7033,9223,54090). The association between drinking green tea and gastric cancer-related mortality has also been investigated, A large-scale population study in Japan suggests that drinking 5 or more cups of green tea daily is not associated with a reduced risk of gastric cancer-related mortality when compared to drinking less than one cup daily (14498). Discrepancies might be related to the temperature of the green tea. The most recent meta-analysis suggests that intake of cold or warm green tea, and not hot green tea, is associated with a modest reduction in gastric cancer risk (111025).
• Gingivitis. It is unclear if oral or topical green tea is beneficial for gingivitis. Details: A meta-analysis of clinical research shows that use of oral or topical products containing green tea modestly reduces gingivitis and gingival bleeding when compared with control products, including triclosan toothpaste, placebo, and chlorhexidine rinse. However, a sub-group analysis shows that a green tea rinse is no more effective than a chlorhexidine rinse. Green tea products used in these studies were heterogeneous and included mouth rinse, gel, paste, tea, strips, and capsules (107156). Many of these studies are limited by a lack of clear blinding. A more recent clinical study in children ages 10-14 years with plaque and gingivitis shows that using a mouthwash containing green tea extract 5% twice daily, alone or at half-strength with ginger extract, for 30 days reduces plaque and gingivitis severity. The mouthwash containing the combination of green tea and ginger extract was most effective, and the green tea extract alone was at least as effective as chlorhexidine (107163).
• Headache. Although there has been interest in using oral green tea for headache, there is insufficient reliable information about the clinical effects of green tea for this condition.
• Hypertension. The evidence is mixed as to whether drinking green tea reduces the risk of hypertension and whether oral green tea lowers blood pressure in patients with hypertension. Details: Some epidemiological research from China shows that drinking 120-599 mL of green tea or oolong tea daily is associated with a 46% lower risk of developing hypertension when compared with non-habitual tea drinkers; drinking more than 600 mL daily is associated with a 65% reduced risk (12518). In contrast, drinking green tea daily is associated with a 38% increased odds of having hypertension when compared with never drinking green tea in elderly Chinese males, but not females (107166). Green tea may help lower blood pressure in patients with or without hypertension; however, the evidence is mixed, and any reductions appear to be small. A meta-analysis of two clinical trials in patients with hypertension shows that drinking green tea for 4-16 weeks reduces systolic, but not diastolic, blood pressure by about 6 mmHg (104583). Meta-analyses in patients with or without hypertension, including overweight or obese adults, suggest that green tea reduces systolic and diastolic blood pressure by 1-3 mmHg (90146,90155,90161,98423,102726,111018). Some studies used green tea, made by boiling a 3 gram tea bag with 150 mL water and then waiting for 5 minutes and consuming three times daily approximately 2 hours after each meal for 4 weeks (90159), or green tea extract up to 1500 mg daily for up to 12 weeks (111018), including a specific product (Olimp Labs) 379 mg, taken daily with the morning meal for 3 months (54068).
• Hypotension. It is unclear if oral green tea is beneficial for postprandial hypotension in elderly adults. Details: Some research shows that consuming caffeinated beverages increases blood pressure in elderly people with postprandial hypotension (11834,11835). Also, preliminary clinical research shows that drinking 400 mL of green tea before lunch increases postprandial systolic and diastolic blood pressure by 15 mmHg and 6 mmHg, respectively, in older elderly people with postprandial hypotension (89482).
• Infertility. Oral green tea has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in females with a history of problems conceiving shows that taking three capsules daily of a proprietary blend of Vitex agnus-castus extract (standardized to 0.5% agnusides), green tea extract (standardized to 50% phenols), L-arginine, vitamins E, B6, and B12, folate, iron, magnesium, zinc, and selenium (FertilityBlend, The Daily Wellness Company) for three menstrual cycles increases the rate of pregnancy at three months by 61% when compared with placebo (41479).
• Influenza. It is unclear if oral green tea is beneficial for preventing the flu. Details: A meta-analysis of five clinical trials in individuals with or without prior influenza vaccination shows that use of green tea catechins, either in capsule form or as a gargled liquid, reduces the rate of influenza infections by 33% when compared with control. Also, a meta-analysis of observational research has found that gargling with or consuming green tea containing catechins is associated with a 48% reduced risk of influenza when compared with not taking green tea catechins. More information is needed to compare the efficacy of the different forms of green tea catechins (107152). Some epidemiological research not included in this meta-analysis has found that drinking at least 5 cups of green tea weekly is associated with a 32% reduced odds of developing confirmed influenza when compared with drinking less than one cup weekly. A sub-group analysis suggests that this association is only evident in individuals who had not received the influenza vaccination (104608). Conversely, other preliminary research shows that gargling with green tea at least three times daily for 90 days does not prevent influenza in high school students when compared with water (90150). Green tea has also been evaluated in combination with theanine. One small study shows that taking a combination of green tea catechins (THEA-FLAN 90S, Ito-en Co) 378 mg standardized to 270 mg of epigallocatechin gallate (EGCG) with theanine 210 mg daily for 5 months reduces the risk of developing clinically defined influenza, but not laboratory-confirmed influenza infection, when compared with placebo (54021). Other preliminary clinical research in healthy adults shows that taking two capsules of a specific formulation (ImmuneGuard, Nutraceutical Holdings LLC) containing L-theanine (Suntheanine, Taiyo International) plus EGCG (Sunphenon, Taiyo International) twice daily for 3 months reduces the number of subjects with cold or flu symptoms and the number of days with symptoms when compared with placebo (53754).
• Japanese cedar pollinosis. It is unclear if oral green tea is beneficial for preventing Japanese cedar pollinosis symptoms. Details: In patients with Japanese cedar pollinosis, clinical research shows that drinking Benifuuki green tea drink 350 mL containing O-methylated catechin 34-40 mg daily beginning 6-10 weeks before pollen exposure until the end of pollen season can reduce nasal and ocular symptoms. Clinical research compared the "benifuuki" drink enriched in O-methylated EGCG with that of another green tea "yabukita," containing no O-methylated EGCG (53884,90156).
• Kidney stones (nephrolithiasis). It is unclear if drinking green tea prevents kidney stones. Details: Population research suggests that drinking green tea is associated with a reduced risk of having kidney stones. This risk was 22% lower in males and 16% lower in females when compared with never or former green tea drinkers (104613).
• Leukemia. It is unclear if drinking green tea is beneficial for leukemia prevention. Details: Although some large epidemiological studies suggest that drinking green tea reduces the risk of leukemia by 51% to 80% (53799,90183,102723), a meta-analysis of generally low-quality population research shows a variable association between green tea intake and risk of leukemia (102716).
• Liver cancer. It is unclear if drinking green tea is beneficial for liver cancer prevention. Details: Two meta-analyses of epidemiological research suggest that green tea consumption is associated with a reduced risk of liver cancer (97132,111016). The most recent meta-analysis in approximately 1.5 million adults in Asia, North America, and Europe suggests that the highest intake of green tea is associated with a 20% reduced risk of liver cancer when compared with the lowest. The most benefit was associated with consumption of at least 4 cups daily (111016). Another meta-analysis that included studies conducted in Japan, China, or Singapore suggests that higher green tea consumption is associated with a 12% reduced incidence of liver cancer when compared with the lowest consumption of green tea. However, the benefit appears to be limited to females; green tea consumption was not associated with a reduced risk of liver cancer in males (97132). A large epidemiological study in Chinese females also suggests that green tea consumption is associated with a reduced risk of liver cancer. Consuming a cumulative intake of 30 kg dried green tea leaves is associated with a 46% reduced risk of primary liver cancer over a median of 18 years when compared with never drinking green tea (111030). In contrast, some individual epidemiological studies suggest that green tea consumption is not associated with a reduced risk of liver cancer in Japanese individuals (90181,102716).
• Lung cancer. It is unclear if drinking green tea is beneficial for lung cancer prevention. Details: Individual observational studies and meta-analyses of population research have yielded conflicting evidence about the effects of green tea on lung cancer risk (13190,14498,53829,90177,102716). Although one meta-analysis of population research suggests that the highest intake of green tea does not reduce lung cancer risk when compared to the lowest intakes (102716), other analyses suggest that increasing green tea consumption by two cups daily is associated with an 18% decreased risk of lung cancer, and that drinking 7-10 cups of green tea daily is associated with an 18% to 33% reduced risk of lung cancer when compared with drinking less than one cup daily (53829,90177).
• Mental alertness. It is unclear if oral green tea is beneficial for mental alertness. Details: Green tea contains caffeine. Consumption of caffeinated beverages seems to prevent a decline in alertness and cognitive capacity when consumed throughout the day (4221,4224). Also, combining caffeine with glucose as an "energy drink" seems to improve mental performance better than placebo or either caffeine or glucose alone (13732). However, there is mixed evidence regarding the effects of green tea on mental alertness.
• Metabolic syndrome. It is unclear if oral green tea is beneficial for improving metabolic parameters in people with this condition. Details: Preliminary clinical research shows that taking green tea extract 1000 mg daily or drinking four cups of green tea daily for 8 weeks does not improve metabolic syndrome features, including waist circumference, blood pressure, cholesterol levels, or blood sugar in obese patients with metabolic syndrome when compared to control (53995).
• Multiple myeloma. It is unclear if drinking green tea is beneficial for multiple myeloma prevention. Details: Population research suggests that drinking at least 5 cups of green tea each day is not associated with a reduced risk of multiple myeloma when compared with never drinking green tea (102723).
• Myocardial infarction (MI). It is unclear if drinking green tea prevents MI or if drinking green tea prevents mortality in patients with a previous MI. Details: When compared with drinking less than one cup of green tea daily, epidemiological research in a population at high risk of coronary artery disease has found that drinking more than three cups of green tea daily is associated with a 49% reduced odds of having a past MI as determined by a coronary angiography. A sub-group analysis found that these odds only occurred in individuals consuming both fruits and vegetables more than four times weekly and not in individuals consuming fruits or vegetables less often (104588). In addition, observational research has found that drinking either 1-3 cups or at least 4 cups of green tea daily is associated with 19% and 32% lower odds of MI, respectively, when compared to drinking less than 1 cup daily (97134). In patients with a previous MI, drinking at least 7 cups of green tea daily is associated with a 53% reduced odds of all-cause mortality over a median of 18.5 years when compared with not drinking green tea (107160).
• Nasopharyngeal cancer. It is unclear if drinking green tea is beneficial for nasopharyngeal cancer prevention. Details: A meta-analysis of epidemiological research has found that the highest intake of green tea is associated with a 51% reduced risk of nasopharyngeal cancer when compared with the lowest intake (102716).
• Nonalcoholic fatty liver disease (NAFLD). It is unclear if oral green tea is beneficial for NAFLD. Details: Clinical research shows that drinking green tea 700 mL containing 1080 mg of catechins daily for 12 weeks does not affect body weight or body mass index (BMI), but does reduce body fat percentage from 34% to 32%, when compared with drinking either green tea 700 mL containing 200 mg of catechins or a control tea. Also, the liver-to-spleen attenuation ratio increased by 11% when compared with baseline (90168). Meta-analyses of four studies in patients with NAFLD show that taking green tea extract 500-1000 mg daily or green tea catechins 600 mg daily improves liver function tests when compared with placebo (98459,102720). One meta-analysis also shows that these doses improve BMI, total cholesterol, and low-density lipoprotein (LDL) cholesterol when compared with placebo (98459).
• Non-Hodgkin lymphoma. It is unclear if drinking green tea is beneficial for non-Hodgkin lymphoma prevention. Details: Population research has found that drinking at least 3.5 cups of green tea daily is not associated with a reduced risk of non-Hodgkin lymphoma when compared with never drinking or drinking less than 1 cup of green tea daily (102005,102723).
• Obesity. Evidence for the use of green tea products for weight loss is conflicting. The conflicting findings may be related to the caffeine and catechin content of the studied products, as well as the physical activity level of the individual. Details: Many clinical studies show that drinking green tea or taking green tea extract that contains caffeine (about 70-200 mg) and high levels of catechins (about 576-886 mg) daily for 12-24 weeks modestly improves weight loss when compared to control in overweight individuals or patients with obesity (8114,37725,53906,90184). A meta-analysis of 25 randomized clinical trials shows that taking green tea extract containing caffeine results in an additional weight loss of 1.8 kg when compared with a control group not taking green tea extract (102719). In addition, a meta-analysis of clinical trials shows that taking green tea reduces body weight by 0.4 kg in mainly overweight individuals with type 2 diabetes (104610). Some research also shows that drinking green tea or taking green tea extract containing high levels of catechins but no caffeine reduces weight and visceral fat in overweight individuals or patients with obesity when used for up to 12 weeks (53994,54039,90184). In these clinical trials, the following doses have been used: two capsules of green tea extract daily standardized to containing 870 mg of catechins (460 mg EGCG) or 4 cups of green tea daily standardized to contain 928 mg of catechins (440 mg EGCG) for 8 weeks (53994); a specific decaffeinated green tea extract (Sunphenon 90LB, Taiyo Kagaku Ltd.) 530 mg twice daily for 6 weeks (54039); catechin-enriched green tea beverages providing 234-886 mg of catechins once or twice daily for approximately 3 months (37705,53906,90184); a specific green tea extract (AR25, Exolise, Arkopharma), taken as four capsules standardized to contain 375 mg of catechins (epigallocatechin gallate 270 mg) in two divided doses daily for 12 weeks (8114). Some research has also shown weight loss benefits of multi-ingredient products or diets containing green tea. Multi-ingredient products have included an herbal mixture of garcinia extract 650 mg, green tea extract 100 mg, coffee extract 75 mg, and banaba extract 25 mg per tablet (IQP-GC-101, InQpharm Europe Ltd.) 30 minutes before meals twice daily for 12 weeks (90137) and a specific product (Sanavita Industry, Piracicaba) containing powdered green tea (40 mg of caffeine), orange pulp, vitamin C, zinc, and selenium, taken as 20 grams in two divided doses daily for 8 weeks (90134). Drinking green tea has also been used as part of a Mediterranean diet also including Wolffia globose (109888). However, many studies show conflicting results (37715,37753,54035,98419,98420,98422). Reasons for these inconsistent findings are not entirely clear, but may relate to the use of decaffeinated green tea products, the use of green tea products containing low catechin amounts, or the presence and type of concomitant exercise. Some research shows that green tea extract containing a lower catechin amount (491 mg daily) or decaffeinated green tea products do not improve weight loss when compared with placebo in patients with obesity (37753,54035,98419). One meta-analysis of 15 clinical studies including about 1240 patients with obesity shows that using green tea products that are decaffeinated does not improve body weight, body mass index, or waist circumference when compared with control, while green tea products containing catechins 576-714 mg daily and caffeine do improve these outcomes (16892). Taking green tea after weight loss does not seem to improve weight maintenance when compared with control (14428,54076). Other clinical research shows that green tea does not improve weight loss in individuals with obesity who are already participating in exercise, such as walking and interval sprinting (37715,98420). In contrast, another small clinical study shows that taking green tea 500 mg daily for 10 weeks while participating in HIIT improves weight, body fat percentage, triglycerides, and low-density lipoprotein (LDL) cholesterol levels when compared with either green tea or HIIT alone. However, it appears that the majority of these improvements are due to participation in HIIT (100201). There is also some limited research in children. One small clinical trial in obese children ages 6-16 years shows that taking green tea providing 576 mg catechins daily for 24 weeks modestly reduces waist circumference, as well as systolic blood pressure and low-density lipoprotein (LDL) cholesterol, when compared with taking green tea providing 75 mg catechins daily. However, there were no significant difference between groups for other anthropometric measures or cardiovascular risk factors (37743). Another clinical trial in obese females ages 6-10 years who were also given diet and exercise advice shows that taking decaffeinated green tea polyphenols 400 mg daily for 12 weeks modestly reduces fat mass, but does not affect other anthropometric measures, when compared with placebo. Also, taking green tea polyphenols modestly reduces ovary volume, but has no effect on other measures of early puberty, such as breast development, uterine volume, or levels of sex hormones (107162).
• Oral cancer. It is unclear if oral green tea is beneficial for oral cancer prevention. Details: Meta-analyses of epidemiological research suggest that the highest intake of green tea is associated with a 20% to 29% reduction in risk of oral cancer when compared with the lowest intake (90180,102716). Also, preliminary clinical research in patients with high-risk oral premalignant lesions shows that taking a green tea extract 500-1000 mg/m2 three times daily after meals for 12 weeks increases the rate of clinical and histological response when compared with placebo (53936).
• Oral leukoplakia. It is unclear if drinking green tea and concomitantly applying topical green tea to lesions is beneficial for oral leukoplakia. Details: Preliminary clinical research in patients with oral leukoplakia shows that drinking 3 grams of a mixed tea product containing green tea daily for 6 months, while also topically applying a 10% mixed tea product in the mouth three times daily, reduces oral lesion size by about 38%, compared with a 3% increase in those taking placebo. It is not clear if this effect is due to green tea, the other ingredients, or the combination (4213).
• Osteopenia. It is unclear if oral green tea is beneficial for preventing osteopenia. Details: Population research suggests that drinking green tea for 10 years is associated with increased bone mineral density (8116). Other population research suggests that drinking less than one cup of green tea daily is associated with an 81% to 85% increased odds of having osteopenia when compared with drinking green tea 1-3 times daily (111026). Preliminary clinical research in postmenopausal adults with osteopenia shows that taking capsules containing green tea polyphenols 500 mg (233 mg as epigallocatechin-3-gallate or EGCG) daily, possibly while practicing tai chi 60 minutes three times weekly, for 24 weeks improves serum markers of bone turnover and muscle strength when compared to baseline (54040). However, the results from this study are limited by a lack of control group and the fact that diagnostic measures of bone health, such as T-score or Z-score, were not assessed.
• Osteoporosis. It is unclear if oral green tea is beneficial for preventing osteoporosis. Details: Population research suggests that drinking green tea for 10 years is associated with increased bone mineral density (8116). Other population research suggests that drinking less than one cup of green tea daily is associated with up to a 91% increased odds of having osteoporosis when compared with drinking green tea 1-3 times daily (111026). More recent clinical research shows that taking decaffeinated green tea extract supplying approximately 1315 mg of catechins (843 mg as EGCG) daily does not improve bone mineral density, T-score, or Z-score in postmenopausal adults (98419).
• Overall mortality. Some population research suggests that drinking green tea may reduce the risk of overall mortality by a small amount. Details: A meta-analysis of population research in Japanese adults found that drinking at least 5 cups of green tea daily is associated with reduced risk of all-cause mortality when compared with drinking less than 1 cup daily (102002). Another meta-analysis of population research found that each one cup per day increase in green tea consumption is associated with a 3% reduced risk of all-cause mortality (102728). However, more recent population research has found that although drinking green tea is associated with reduced risk of all-cause mortality in patients with a previous MI and stroke, drinking as much as 7 cups of green tea daily is not associated with a reduced odds of all-cause mortality over a median of 18.5 years in individuals with no history of stroke or MI when compared with not drinking green tea (107160).
• Pancreatic cancer. It is unclear if drinking green tea is beneficial for pancreatic cancer prevention. Details: A meta-analysis of population research suggests that the highest intake of green tea is not associated with a reduced risk of pancreatic cancer when compared with the lowest intake (102716). However, one epidemiological study suggests that drinking green tea is associated with a reduced risk of pancreatic cancer (54096).
• Parkinson disease. Although consuming caffeinated beverages might reduce the risk of developing Parkinson disease, it is unclear if oral green tea prevents or improves symptoms in people with this condition. Details: There is some evidence from large-scale epidemiological studies that the incidence of Parkinson disease decreases with increased consumption of caffeinated beverages such as coffee, tea, and cola. For men, the effects seem to be dose related. Men consuming a total of 421-2716 mg of caffeine (approximately 5-33 cups of tea) from any source daily seem to have the greatest reduction in risk. However, there seems to be a significant reduction in risk even with consumption of as little as 124-208 mg caffeine daily (approximately one to three cups tea) (6022). In females, the effects do not seem to be dose related. Moderate consumption of approximately 1-4 cups daily seems to provide the most reduction in risk (1238). It is unclear if consuming green tea is more or less effective than other caffeinated beverages for reducing Parkinson disease risk.
• Periodontitis. It is unclear if oral or topical green tea is beneficial for improving oral health or improving periodontal disease. Details: Epidemiological research has found that intake of green tea is inversely associated with symptoms of periodontal disease, including probing depth, attachment loss, and bleeding on probing (53844). A small clinical trial shows that taking green tea extract 1.55% by weight in chewable candy for 28 days appears to reduce plaque accumulation and gingival inflammation (7594). A small clinical trial in patients with chronic periodontitis shows that applying a gel containing green tea extract 1 gram/100 mL into the periodontal pocket as an adjunct to scaling improves gingivitis, periodontal disease, and clinical attachment by 7%, 112%, and 116%, respectively, when compared with placebo gel (90135). A meta-analysis of low-quality clinical research also shows that use of oral or topical products containing green tea modestly improve clinical attachment when compared with control products, including triclosan toothpaste and placebo. Green tea products included gel, paste, and tea (107156).
• Pneumonia. It is unclear if drinking green tea is beneficial for pneumonia prevention. Details: Epidemiological research in Japanese females has found that consuming green tea is associated with a lower risk of death from pneumonia when compared to those who do not drink green tea (53897). However, other epidemiological research in hospitalized elderly Japanese adults has found that there is no association between green tea consumption during the past month and prevalence of pneumonia at time of hospitalization (107161).
• Polycystic ovary syndrome (PCOS). It is unclear if oral green tea is beneficial for PCOS. Details: A meta-analysis of 4 small clinical trials shows that taking green tea modestly reduces weight in patients with PCOS when compared with placebo. However, there was no effect on other endpoints including body mass index (BMI), percent body fat, or waist or hip circumference. Three studies in the meta-analysis used green tea 1000-2000 mg/daily in tablets or capsules; the other study used green tea powder providing epigallocatechin gallate 1620 mg daily (111019). However, the included studies were small and utilized heterogeneous dosing regimens. Subsequently, a moderate-sized clinical study in patients with PCOS shows that taking green tea leaf powder, 500 mg twice daily for 1 week followed by 1500 mg daily for 3 months, improves menstrual cycle regularity, but does not reduce BMI or waist or hip circumference, when compared with metformin or placebo (114894).
• Postoperative pain. It is unclear if rinsing the mouth with green tea is beneficial for postoperative pain associated with molar removal. Details: In patients undergoing third molar extraction, a small clinical trial shows that using 15 mL of a mouthwash containing green tea extract 5 grams/100 mL twice daily, beginning the day after surgical removal of impacted molars and continuing for 7 days thereafter, reduces pain by 60% and analgesic use during the first three days when compared with using a mouthwash that does not contain green tea (90141).
• Prostate cancer. It is unclear if drinking green tea or taking green tea catechins by mouth is beneficial for prostate cancer treatment or prevention. Details: Green tea catechins have been evaluated for reducing prostate cancer risk in high-risk patients (14127,98421,102716). A meta-analysis of results from three clinical trials shows that taking green tea catechins 400-600 mg daily for 12-30 months reduces the risk of prostate cancer by approximately 62% when compared with placebo in high-risk patients (98421). However, another meta-analysis including two of these studies plus one additional does not show that taking green tea catechins reduces the incidence of prostate cancer in high-risk patients (102716). Most population research has found that drinking higher amounts of green tea is not associated with a reduced risk for prostate cancer when compared with those who never or rarely drink green tea (14128,54036,53741,53753,90153,90181,98421). However, one meta-analysis of population research found that people who drink very high amounts of green tea (7-15 cups daily) have a 19% to 44% reduced risk of prostate cancer (98421). Another population study found that higher green tea intake is associated with a reduced risk of advanced, but not overall, prostate cancer risk (53753). In April 2012, the US Food and Drug Administration (FDA) determined that it would allow a qualified health claim stating that consuming green tea may reduce the risk of prostate cancer, although the FDA has concluded that there is very little scientific evidence to support this claim (102106). Additionally, most clinical research shows that drinking large amounts of green tea or taking green tea extract does not reduce disease progression in patients with prostate cancer (11366,53726). Green tea and green tea catechins have also been evaluated for reducing prostate specific antigen (PSA) levels. A meta-analysis of clinical research in patients with or at risk of prostate cancer shows that taking green tea or green tea extract for 3 weeks to 12 months does not modify PSA levels when compared with water or placebo. However, sub-analyses suggest that there is significant heterogeneity with respect to findings between geographical locations, with some evidence of benefit in studies conducted in the US (107155).
• Radiation dermatitis. It is unclear if topical green tea is beneficial for preventing radiation dermatitis. Details: Preliminary clinical research in patients undergoing radiotherapy after breast cancer surgery shows that spraying epigallocatechin gallate (EGCG) over the radiation field prevents the development of at least moderate severity radiation dermatitis by 30% when compared with saline as placebo. Also, occurrence of symptoms was delayed by about 2.7 days and symptom severity was reduced. EGCG 660 mcmol/L was sprayed 3 times daily from the first day of radiation until 2 weeks after completion at 0.05 mL per squared cm (111031). The interpretation of these results is limited by the unbalanced treatment groups.
• Radiation-induced diarrhea. It is unclear if oral green tea is beneficial for reducing diarrhea associated with radiotherapy. Details: A small clinical trial shows that taking a green tea tablet (Camgreen, Iran Giahessence Pharmacy Co.) 450 mg daily for 5 weeks during pelvic irradiation reduces the frequency of diarrhea in patients undergoing radiotherapy treatment. In the fifth week of treatment, 19% of patients taking green tea had diarrhea, compared with approximately 62% of those taking placebo (104614).
• Radiation-induced nausea and vomiting. It is unclear if oral green tea is beneficial for reducing vomiting associated with radiotherapy. Details: A small clinical trial shows that taking a green tea tablet (Camgreen, Iran Giahessence Pharmacy Co.) 450 mg daily for 5 weeks during pelvic irradiation does not reduce the frequency of vomiting when compared with placebo in patients undergoing radiotherapy treatment (104614).
• Renal cell carcinoma. It is unclear if oral green tea is beneficial for preventing kidney cancer. Details: Epidemiological research suggests that green tea intake is not associated with risk of kidney cancer over a mean of 19 years in Japanese adults. However, in females, consuming at least 5 cups of green tea daily, but not lesser amounts, is associated with a 55% reduced risk of kidney cancer when compared with rare intake (111022).
• Skin cancer. Although there has been interest in using oral or topical green tea for skin cancer, there is insufficient reliable information about the clinical effects of green tea for this condition.
• Stress. It is unclear if oral green tea is beneficial for stress reduction. Details: Preliminary clinical research shows that taking a specific brand of green tea extract (Teavigo, DSM) 300 mg orally for 7 days reduces stress and increases calmness when compared with placebo in healthy individuals (54055).
• Stretch marks (striae distensae). It is unclear if topical green tea is beneficial for stretch marks. Details: A small clinical study in young adult females shows that applying a green tea extract 3% cream to stretch marks on the leg twice daily for 8 weeks reduces stretch mark severity when compared to baseline (114893). The validity of this study is limited by the lack of a control group.
• Stroke. It is unclear if consumption of green tea is associated with a reduced risk of stroke or with reduced all-cause mortality in patients with a previous stroke. Details: Large-scale population research in Japanese individuals suggests that consuming at least 3-5 cups of green tea daily is associated with a reduced risk of cerebrovascular mortality when compared with drinking less than 1 cup daily. This association appears to be primarily related to a decrease in risk for cerebral infarction or hemorrhage (14498,54080,102002). Other population research suggests that drinking 1-3 cups of green tea daily is associated with a 36% reduced odds of stroke when compared with drinking less than 1 cup daily, while drinking 4 or more cups daily has no effect. Also, green tea consumption was not associated with reduced incidence of cerebral hemorrhage or infarction in this study (97134). Meta-analyses of population research suggest that an increase of 1 cup per day in green tea consumption is associated with a 6% reduced risk of stroke or cerebral hemorrhage (102728,111021). A prospective, observational study also suggests that higher intake of tea, including green and black tea, of at least 2 cups daily is associated with a 16% reduced risk of stroke when compared with not drinking tea. This study also found that drinking 2-3 cups daily of each tea and coffee is associated with a 38% reduced risk of stroke when compared with not drinking tea and coffee. The combination of 0.5-1 cups of coffee and 2-3 cups of tea daily, but not tea alone, was associated with a 50% reduced risk of post-stroke dementia when compared with not drinking tea and coffee (107204). In patients with a previous stroke, drinking at least 3 cups of green tea daily is associated with a 48% to 62% reduced odds of all-cause mortality over a median of 18.5 years when compared with not drinking green tea (107160).
• Sunburn. It is unclear if oral or topical green tea is beneficial for preventing ultraviolet radiation-induced erythema. Details: A meta-analysis of three small clinical trials shows that taking green tea catechins 540-1402 mg daily for 6 to 12 weeks has a small to moderate protective effect against ultraviolet radiation-induced erythema when compared with placebo, especially at lower doses of ultraviolet radiation. A single topical dose of green tea ingredients may also be beneficial, but data is limited (107153).
• Systemic lupus erythematosus (SLE). It is unclear if oral green tea is beneficial for SLE. Details: Preliminary clinical research shows that taking green tea extract 500 mg (containing 22% polyphenols) twice daily for 3 months modestly improves disease activity, general health, and vitality when compared with placebo (97136).
• Tinea pedis. It is unclear if a topical green tea footbath is beneficial for athlete's foot. Details: In bedridden, elderly patients with cognitive deficiency, use of a footbath containing a 0.1% green tea extract for 15 minutes once daily for 12 weeks does not improve symptoms of athlete's foot, but does improve skin condition, when compared with a footbath not containing green tea. The green tea extract Sunphenon BG-3 (Taiyo Kagaku Co. Ltd., Yokkaichi), prepared by dissolving 5 grams of the Sunphenon BG-3 product in 5 liters of water to create a 0.1% green tea solution, was used (90151).
• Tooth extraction. Topical green tea has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small, split-mouth clinical study in patients undergoing third molar extractions shows that applying a gel containing green tea extract 0.5% and hyaluronic acid into the surgical site immediately after extraction and three times daily for 7 days improves some post-operative outcomes, such as reducing exudate or facial edema when compared with placebo (114895). It is unclear if these effects are due to green tea, hyaluronic acid, or the combination.
• Ulcerative colitis. It is unclear if oral green tea is beneficial for ulcerative colitis. Details: Preliminary clinical research in patients with mild to moderate ulcerative colitis shows that taking a specific green tea product (Polyphenon E, Mitsui-Norin) 200 mg or 400 mg twice daily for 8 weeks may increase the number of people who respond to therapy and achieve remission when compared with placebo. After treatment, 10 of 15 patients in the green tea extract group responded to therapy and 8 of 15 patients achieved remission, compared with 0 in the placebo group (90140).
• Upper respiratory tract infection (URTI). It is unclear if gargling and swallowing green tea is beneficial for reducing URTI symptoms. Details: Preliminary clinical research shows that gargling and swallowing green tea (Morgentau, Ronnefeld KG) 100 mL daily over 4 days is less effective than proprietary labdanum lozenges (CYSTUS052, Dr Pandalis Urheimische Medizin GmbH & Co.) for upper respiratory tract symptoms in patients with URTIs (53867).
• Urinary tract infections (UTIs). It is unclear if oral green tea is beneficial for reducing UTI symptoms. Details: A small clinical study in females with acute uncomplicated cystitis shows that adding green tea 2000 mg daily for 3 days to treatment with trimethoprim-sulfamethoxazole reduces symptoms of cystitis when compared with placebo (99799). This study is limited by its small size and the lack of information on antibiotic resistance in each treatment group.
• Wrinkled skin. It is unclear if oral or topical green tea is beneficial for wrinkles. Details: Some preliminary clinical research shows that taking green tea catechins 175 mg twice daily for two years does not reduce signs of photo-aging of the skin in females with facial photo-aging when compared with placebo (53873). However, using a combination of topical green tea 10% cream and oral green tea extract 300 mg twice daily for 8 weeks seems to improve skin elasticity in females with moderate photo-aging based on microscopic analysis, although the clinical appearance of the skin does not seem to significantly improve (53731). Other preliminary clinical research shows that consuming one liter of a beverage with green tea polyphenols for 12 weeks improves skin elasticity, roughness, and hydration in middle-aged females when compared with placebo (54030). More evidence is needed to rate green tea for these uses.

(Read more about GREEN TEA)

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Aging. Although there has been interest in using oral holy basil for aging, there is insufficient reliable information about the clinical effects of holy basil for this purpose.
• Asthma. Although there has been interest in using oral holy basil for asthma, there is insufficient reliable information about the clinical effects of holy basil for this condition.
• Dental plaque. Small clinical studies suggest that topical use of holy basil mouthwash, gel, or toothpaste may modestly reduce the severity of dental plaque. Details: Small clinical studies in patients with mild to moderate dental plaque or gingivitis shows that using 10 mL of a mouthwash containing holy basil leaf extract 4% twice daily for 30 days reduces plaque severity by about 17% to 28% when compared with baseline (91570,103621). In one study, this effect was significant when compared with a placebo mouthwash and similar to a mouthwash containing chlorhexidine 0.12% (91570), whereas the other study did not conduct comparisons between study groups (103621). A small clinical study in patients with chronic gingivitis shows that applying holy basil extract 2% gel as a gingival massage twice daily for 30 days reduces plaque severity when compared with baseline (110030). The validity of this finding is limited by the lack of statistical comparison to the other study groups. Also, a small clinical trial in children 14-15 years of age shows that brushing with toothpaste containing holy basil leaf extract 4% twice daily for 3 weeks reduces plaque severity when compared with placebo, with similar improvements when compared with a fluorinated toothpaste (104183). Holy basil has also been evaluated in combination with other ingredients. A small study shows that rinsing with 10 mL of a solution containing tea tree oil, clove, and holy basil (0.2% to 0.3% of each), for 30 seconds twice daily for 21 days, reduces plaque formation by 64%. This reduction is similar to a 72% reduction seen in the active control group using a mouth rinse containing thymol, eucalyptol, menthol, and methyl salicylate (91446).
• Diabetes. Small clinical studies suggest that oral holy basil may modestly improve glycemic control in patients with diabetes. Details: One small clinical trial in adults with type 2 diabetes shows that taking holy basil dried leaf powder 2.5 grams daily for 4 weeks decreases fasting and postprandial blood glucose by 18%, compared with a 7% reduction in those taking placebo (12242). Another small clinical study in patients with type 2 diabetes shows that taking holy basil 250 mg twice daily in combination with glyburide 5 mg daily for 3 months reduces fasting blood glucose by 16%, postprandial blood glucose by 13%, and glycated hemoglobin (HbA1c) levels by 18% when compared with glyburide alone (91571).
• Dyspepsia. Although there has been interest in using oral holy basil for dyspepsia, there is insufficient reliable information about the clinical effects of holy basil for this purpose.
• Generalized anxiety disorder (GAD). It is unclear if oral holy basil is beneficial in patients with GAD. Details: One small, uncontrolled clinical study in patients with GAD shows that taking holy basil leaf extract 500 mg twice daily following meals for 60 days reduces anxiety and associated symptoms of stress and depression when compared to baseline (19575). The validity of these findings is limited by a lack of control group.
• Gingivitis. Small clinical studies suggest that topical use of holy basil mouthwash or toothpaste may modestly improve gingivitis. Details: Small clinical studies in patients with mild to moderate dental plaque or gingivitis shows that using 10 mL of a mouthwash containing holy basil leaf extract 4% twice daily for 30 days reduces gingivitis by about 23% to 40% when compared with baseline (91570,103621). In one study, these effects were significant when compared with placebo mouthwash and similar to those of a mouthwash containing chlorhexidine 0.12% (91570), whereas the other study did not conduct statistical comparisons between study groups (103621). A small clinical trial in children 14-15 years of age shows that brushing with toothpaste containing holy basil leaf extract 4% twice daily for 3 weeks reduces the severity of gingivitis when compared with placebo, with similar improvements when compared with a fluorinated toothpaste (104183). However, a small clinical study in patients with chronic gingivitis shows that applying holy basil leaf extract 2% gel as a gingival massage twice daily for 30 days does not reduce gingivitis severity when compared with baseline (110030). Holy basil has also been evaluated in combination with other ingredients. A small clinical study shows that rinsing with 10 mL of a solution containing tea tree oil, clove, and holy basil (0.2% to 0.3% of each), for 30 seconds twice daily for 21 days, reduces gum inflammation by 76%. This reduction is similar to a 70% reduction seen in the active control group using a mouth rinse containing thymol, eucalyptol, menthol, and methyl salicylate (91446).
• Headache. Although there has been interest in using oral holy basil for headache, there is insufficient reliable information about the clinical effects of holy basil for this purpose.
• Hepatitis. Although there has been interest in using oral holy basil for hepatitis, there is insufficient reliable information about the clinical effects of holy basil for this condition.
• Hypercholesterolemia. Although there has been interest in using oral holy basil for hypercholesterolemia, there is insufficient reliable information about the clinical effects of holy basil for this purpose.
• Hypertension. Although there has been interest in using oral holy basil for hypertension, there is insufficient reliable information about the clinical effects of holy basil for this purpose.
• Insect repellent. Although there has been interest in using topical holy basil as an insect repellent, there is insufficient reliable information about the clinical effects of holy basil for this purpose.
• Insomnia. It is unclear if oral holy basil is beneficial for sleep problems. Details: A moderate-sized clinical study in adults with stress and sleep problems (i.e., unrefreshing sleep or difficulty falling or staying asleep) shows that taking holy basil 125 mg twice daily for 8 weeks does not improve patient-reported or wearable tracker scores related to sleep when compared with placebo (112416). However, the interpretation of these results is limited by self-reported outcomes and use of a non-validated measurement tool for sleep (i.e., Fitbit device).
• Obesity. It is unclear if oral holy basil is beneficial in overweight or obese patients. Details: One small clinical study in individuals with overweight or obesity shows that taking holy basil extract 250 mg twice daily for 8 weeks slightly reduces body weight and improves levels of triglycerides or low-density lipoprotein (LDL) cholesterol and certain glycemic indices when compared to baseline, but not when compared with no treatment. Holy basil extract also did not improve liver enzymes when compared to baseline or with no treatment (96944).
• Oral submucous fibrosis. It is unclear if topical holy basil paste is beneficial for oral submucous fibrosis. Details: A moderate-sized clinical study in adults with oral submucous fibrosis conducted in India shows that applying a paste containing holy basil extract 250 mg intraorally twice daily for 1 month modestly improves mouth opening scores and patient-reported burning sensation at the 3 month follow up when compared to baseline (112424). However, the validity of these findings is limited by poor methodology and lack of a comparator group.
• Respiratory tract infections. Although there has been interest in using oral holy basil for respiratory tract infections, including bronchitis, common cold, influenza, and tuberculosis, there is insufficient reliable information about the clinical effects of holy basil for these conditions.
• Stress. It is unclear if oral holy basil is beneficial in patients with stress. Details: One small clinical trial in patients experiencing various symptoms of stress shows that taking a specific holy basil extract (OciBest, Natural Remedies Pvt. Ltd.) 400 mg in the morning and 800 mg at night for 6 weeks decreases self-reported symptoms of stress, including forgetfulness, sexual problems and sleep problems of recent origin, and frequency of exhaustion, when compared with placebo (18107). A moderate-sized clinical study in adults with stress and sleep problems shows that taking holy basil 125 mg twice daily for 8 weeks modestly improves stress scores but does not improve individual symptoms related to stress including anxiety, mood disturbance, physical function, depression, fatigue, or sleep disturbance when compared with placebo (112416). However, the interpretation of these findings is limited by self-reported outcome measures and unclear clinical significance.
• Tinea corporis. Although there has been interest in using topical holy basil for tinea corporis, there is insufficient reliable information about the clinical effects of holy basil for this purpose. More evidence is needed to rate holy basil for these uses.

(Read more about HOLY BASIL)

LIKELY INEFFECTIVE

• Alzheimer disease. Lecithin does not improve daily functioning in patients with Alzheimer disease. Details: In patients with Alzheimer disease, taking various types of lecithin, 1.2-45 grams daily for up to 6 months, alone or in combination with various conventional medications, does not improve cognitive function or other measures of disease progression (5149,5151,5152,5156,14817,14823,14825,14837,14838).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Age-related cognitive decline. It is unclear if oral lecithin can slow age-related cognitive decline. Details: A small clinical crossover study in healthy adults aged 64 years and older shows that taking lecithin 26 grams orally daily, alone or in combination with physostigmine, for 5 weeks does not seem to improve memory when compared with placebo (19204).
• Anxiety. Although there is interest in using oral lecithin for anxiety, there is insufficient reliable information about the clinical effects of lecithin for this condition.
• Atopic dermatitis (eczema). Although there is interest in using oral lecithin for atopic dermatitis, there is insufficient reliable information about the clinical effects of lecithin for this condition.
• Bipolar disorder. It is unclear if oral lecithin is beneficial in patients with bipolar disorder. Details: A clinical study in six patients with mania shows that taking lecithin 10 mg three times daily improves symptoms of delusions, incoherent speech, and hallucinations when compared with placebo (14839).
• Dry skin. Although there is interest in using topical lecithin for dry skin, there is insufficient reliable information about the clinical effects of lecithin for this condition.
• Friedreich ataxia. Small clinical studies suggest that oral lecithin is not beneficial in people with Friedreich ataxia. Details: Preliminary clinical research shows that taking lecithin 25 grams orally daily for 1 month does not have any benefit in people with Friedreich ataxia (59298). Other preliminary clinical research shows that taking lecithin for a longer period of 6 months also does not improve performance (19211).
• Hyperlipidemia. Although lecithin may lower cholesterol in healthy people, it does not seem to improve cholesterol levels in people with hyperlipidemia. Details: Some clinical research shows that taking lecithin 20-30 grams daily for up to 11 months decreases cholesterol in healthy people (5147,14820). However, other clinical research shows that lecithin has no effect on low-density lipoprotein cholesterol or total cholesterol levels in people with hyperlipidemia (5148,14820).
• Parkinson disease. It is unclear if oral lecithin is beneficial in patients with Parkinson disease. Details: Preliminary clinical research in patients with Parkinson disease shows that taking lecithin 32 grams daily for 8 weeks does not improve symptoms when compared with placebo (19212).
• Postoperative pain. It is unclear if oral lecithin is beneficial for reducing postoperative pain. Details: Preliminary clinical research shows that taking lecithin 20 grams prior to surgery increases choline levels, but does not reduce postoperative pain after gynecological surgery, when compared with placebo (91231).
• Tardive dyskinesia. It is unclear if oral lecithin is beneficial in patients with tardive dyskinesia. Details: Two small clinical studies in patients with tardive dyskinesia shows that taking lecithin orally for 2 months, alone or in combination with lithium, does not improve symptoms when compared with placebo (14822,14824).
• TPN-associated hepatic steatosis. It is unclear if oral lecithin is beneficial in patients with hepatic steatosis associated with long-term total parenteral nutrition (TPN). Details: A small clinical study in patients on long-term TPN with low choline levels suggests that taking lecithin 20 grams orally twice daily for 6 weeks reduces the degree of hepatic steatosis, compared with no significant changes in those taking placebo (5140).
• Ulcerative colitis. Oral lecithin has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research shows that taking a disease-specific medical food (Profermin, Nordisk Rebalance) containing lecithin, fermented oats, barley malt, and lactobacillus plantarum, as 250 mL twice daily for 24 weeks, decreases disease activity by over 56% when compared with baseline and leads to remission in 46% of patients with mild-to-moderate ulcerative colitis (91228). Other preliminary clinical research in this population shows that taking Profermin 250 mL twice daily for 8 weeks improves disease activity and remission rate when compared with another medical food (Fresubin Original, Fresenius Kabi) (90271). The effects of lecithin alone are unclear. More evidence is needed to rate lecithin for these uses.

(Read more about LECITHIN)

EFFECTIVE

• Bowel preparation. Various magnesium salts are used for cleansing the bowel prior to procedures such as colonoscopy. Details: Various magnesium salts, including citrate, hydroxide, oxide, and sulfate, are ingredients in bowel preparation products available over-the-counter or by prescription only.
• Constipation. Magnesium salts are effective when used short-term orally to treat constipation and chronic idiopathic constipation (CIC). Details: Magnesium citrate, hydroxide, oxide, and sulfate salts are commonly used as laxatives. Magnesium citrate 11.3-17.45 grams has been used; magnesium hydroxide 2.4-4.8 grams, as 30-60 mL of milk of magnesia, has also been used (113483,113484). Magnesium sulfate, also known as Epsom salt, which seems to have the most potent effect, has been used as 10-30 grams (6430,113485). Magnesium salts should only be used for occasional treatment of constipation, and doses should be taken with a full 8-ounce glass of water. Magnesium oxide seems to be beneficial in adults with CIC when taken short-term. Clinical guidelines published by the American Gastroenterology Association and American College of Gastroenterology in 2023 give a conditional recommendation suggesting the use of magnesium oxide over managing CIC without magnesium oxide based on low-quality studies conducted over 4 weeks. The recommended starting dose is 400-500 mg daily with dose titration per symptom response and side effects (112859). A small clinical study in patients with CIC who are not taking chronic medications shows that taking magnesium oxide 1.5 grams in three divided doses daily for 28 days increases spontaneous bowel movements when compared with placebo (104397). It is unknown if magnesium is beneficial for CIC when used long-term.
• Dyspepsia. Magnesium salts are effective when used orally as antacids. Details: Magnesium carbonate, hydroxide, oxide, or trisilicate salts are used orally as antacids to reduce symptoms of gastric hyperacidity or gastroesophageal reflux. Magnesium hydroxide has the fastest onset of action. The onset for magnesium carbonate is slower due to its crystal structure. Magnesium trisilicate has the slowest onset and longest duration of action due to poor solubility (6844). Doses used include magnesium hydroxide 400-1200 mg (5-15 mL of milk of magnesia) up to four times daily, or magnesium oxide 800 mg daily (15).
• Eclampsia. Magnesium sulfate is considered the drug of choice for control of seizures. Details: Intravenous (IV) and/or intramuscular (IM) magnesium sulfate is considered the agent of choice for seizure prophylaxis during eclampsia by the American College of Obstetricians and Gynecologists (ACOG) (15,12591,12592,61012,61184). Typical doses include 4-6 grams of magnesium sulfate by IV infusion in 250 mL of dextrose 5% or normal saline solution, followed by 4-5 grams of magnesium sulfate IM every 4 hours, or 1-3 grams per hour by continuous IV infusion. Doses should be adjusted according to serum levels and urinary excretion, and should not exceed 30-40 grams of magnesium sulfate daily (15,12591). Meta-analyses of clinical research show that treatment with IV or IM magnesium reduces the risk of seizure recurrence by 33% to 69% when compared with phenytoin, and by 47% to 60% when compared with diazepam (19960,60818,60954,60964,61105). One preliminary clinical study shows that lower doses of IV magnesium sulfate (9 grams loading dose and maintenance of 2.5 grams every 4 hours for 24 hours) are as effective as higher doses (14 grams loading dose and maintenance of 5 grams every 4 hours for 24 hours) for reducing the recurrence of eclamptic seizures (89383). It is generally recommended that treatment be continued for at least 24 hours after the last seizure (15). Oral magnesium has not been evaluated for eclampsia.
• Hypomagnesemia. Hypomagnesemia can be effectively treated with oral or parenteral magnesium. Details: Taking magnesium orally or parenterally is helpful for treating and preventing hypomagnesemia associated with alcoholism, cirrhosis of the liver, congestive heart failure (CHF), severe or prolonged diarrhea or vomiting, kidney dysfunction, inflammatory bowel disease (IBD), pancreatitis, malabsorption syndromes, and other conditions (6280,6281,8088,8089). The dose and salt of magnesium for oral replacement therapy should be chosen carefully to avoid causing diarrhea. The gluconate and chloride salts cause less diarrhea, while the oxide salt is more likely to cause diarrhea and should be avoided. Magnesium chloride should also be avoided due to poor solubility which decreases absorption (6430,8099,10664). Orally, magnesium sulfate 3 grams every 6 hours for four doses has been used for hypomagnesemia (15). Parenteral magnesium doses must be individualized according to serum magnesium levels, but a typical starting dose for mild deficiency is 1 gram of magnesium sulfate intramuscularly (IM) every 6 hours for 4 doses (15). For more severe deficiency, 5 grams of magnesium sulfate may be given as an intravenous (IV) infusion in 1 liter of dextrose 5% or normal saline solution over 3 hours (15).
• Pre-eclampsia. Magnesium sulfate is considered the drug of choice for seizure prophylaxis in patients with pre-eclampsia. Details: Intravenous (IV) and/or intramuscular (IM) magnesium sulfate is considered the agent of choice for seizure prophylaxis during pre-eclampsia by the American College of Obstetricians and Gynecologists (ACOG) (12591,12592,61012,61184). Some meta-analyses show that IV administration of magnesium sulfate reduces the risk of eclampsia when compared with placebo, phenytoin, or diazepam in patients with pre-eclampsia (19960,60818,60960,60979). A typical initial dose is 4-5 grams of magnesium sulfate by IV infusion in 250 mL of dextrose 5% or normal saline solution, followed by 4-5 grams of magnesium sulfate IM every 4 hours, or 1-3 grams of magnesium sulfate per hour by continuous IV infusion. Doses should be adjusted according to serum levels and urinary excretion, and should not exceed 30-40 grams of magnesium sulfate daily (15,12591). The optimal duration of prophylaxis has not been determined. A meta-analysis suggests that using a shorter duration of 12 hours or less is not associated with an increase in risk of eclamptic seizures when compared with regimens of 24 hours or longer (108732). However, studies are likely underpowered due to the low incidence of eclampsia. Oral magnesium has been evaluated for the prevention of pre-eclampsia in healthy adults, but taking magnesium citrate 300 mg daily, starting at 12-20 weeks' gestation and continuing until delivery, does not reduce the incidence of pre-eclampsia when compared with placebo (103724).

LIKELY EFFECTIVE

• Cerebral palsy. Most evidence shows that antenatal magnesium reduces the risk of cerebral palsy in preterm infants, although there are some inconsistent results. Details: Most clinical studies and meta-analyses show that antenatal magnesium sulfate reduces the risk of cerebral palsy by about 32% and the risk of motor dysfunction by about 45% in preterm infants (60915,60927,60931,61001,97485,103734,103754,114675,114681). The lowest effective dose of magnesium sulfate seems to be 4 grams intravenously, with or without a maintenance dose of 1 gram/hour until birth or for 24 hours. In obese females, a higher dose, based on body weight, may be needed (97485,97495,103734,103754). However, some studies have inconsistent results (8093,19998,98293,98295,112784). Giving females at risk of imminent preterm birth (prior to 32 weeks), intravenous magnesium sulfate 4.5 grams over 20 minutes followed by 1 gram per hour until birth or for 24 hours, in addition to a standard treatment protocol, does not reduce the incidence of cerebral palsy (112784). Oral magnesium has not been evaluated for this purpose.
• Seizures. Intravenous magnesium sulfate is used for treating seizures of various etiologies. Details: Intravenous magnesium sulfate may be useful for controlling seizures associated with epilepsy, glomerulonephritis, hypothyroidism, and acute nephritis in children (15). Oral magnesium has not been evaluated for this purpose.
• Torsades de pointes. Intravenous magnesium sulfate is the first-line treatment for torsades de pointes after measures to correct precipitating factors have been unsuccessful. Details: Intravenous magnesium sulfate has been used successfully to treat the life-threatening ventricular tachycardia, torsades de pointes (15,6844). The Advanced Cardiac Life Support (ACLS) guidelines of the American Heart Association recommend a dose of 1 to 2 grams diluted in 50-100 mL Dextrose 5% solution given IV over 5-60 minutes, followed by a continuous IV infusion of 0.5-1 gram/hour.

POSSIBLY EFFECTIVE

• Arrhythmia. Magnesium sulfate is effective for the specific type of ventricular tachycardia known as torsades de pointes, and seems to be helpful for treating other types of arrhythmias. Evidence for the role of oral or intravenous magnesium in preventing postoperative arrhythmias is conflicting. Details: Administering magnesium intravenously or orally may be helpful for treating atrial and ventricular tachycardia and fibrillation, and supraventricular tachycardia (9497,13352,13354,13355,13356,60804,60829,60877,61113,111696). Arrhythmias associated with congestive heart failure have been treated with magnesium sulfate 8 grams infused over 12 hours (9497). For rate control in atrial fibrillation, magnesium sulfate 2.5 grams IV over 20 minutes, followed by 2.5 grams IV over 2 hours has been used (13356). For paroxysmal supraventricular tachycardia, single doses of 1-4 grams of magnesium chloride have been used (13352). For atrial tachycardia, 2 grams of magnesium sulfate in 10 mL of dextrose 5% solution has been given IV over 1-10 minutes, followed by 5-10 grams of magnesium sulfate in 250-500 mL dextrose 5% solution as an IV infusion over 5 hours (13354,13355). Research on the effects of intravenous magnesium for preventing arrhythmias after cardiac surgery is conflicting. Some meta-analyses show that intravenous magnesium reduces the risk of atrial fibrillation, ventricular arrhythmias, or supraventricular arrhythmias following cardiac surgery by 23% to 48% when compared with placebo (60814,60826,60828,60838,61008,61033,61181,97487,97490). Doses of magnesium sulfate used include 30 mg/kg in 500 mL normal saline (97490), or 80-100 mg/kg added to the cardioplegia solution (97487). Also, one small study in adults after CABG surgery suggests that taking magnesium hydroxide 1600 mg orally reduces arrhythmia as effectively as receiving magnesium sulfate 2000 mg intravenously (99315). However, other meta-analyses that only include higher-quality trials show that magnesium supplementation does not reduce the risk of ventricular or supraventricular arrhythmias following cardiac surgery (61010,61024,61031,105081). A meta-analysis of clinical trials of intravenous magnesium for prevention of new-onset atrial fibrillation after non-cardiac surgeries shows that it does not reduce the incidence significantly when compared with placebo (112778). However, there was a high risk of bias in the analysis, and variability in types of surgery, and the salt and dose of magnesium used.
• Asthma. Parenteral magnesium sulfate can help to reverse severe acute asthma attacks and reduce the need for hospital admission. It is unclear if nebulized magnesium is beneficial for acute asthma attacks. However, oral magnesium does not seem to be beneficial. Details: Overall, a single dose of intravenous magnesium seems to improve pulmonary function in acute asthma exacerbation and reduce the risk of hospitalization, particularly in patients with severe asthma, and those who have failed initial treatment with nebulized albuterol and intravenous corticosteroids (60888,90023,96483,104398,107365). The typical dose used for adults is 2 grams of magnesium sulfate infused over 20 minutes (15). For children, 25-75 mg/kg, to a maximum of 2 grams, infused over 20-30 minutes has been used (15,96483,107365). However, a post-hoc analysis of one large clinical trial (104400) designed to assess nebulized magnesium in children with acute asthma has found that adding IV magnesium to nebulized magnesium is associated with greater odds of hospitalization when compared with no IV magnesium (105919). This post-hoc analysis did not differentiate between precautionary and necessary hospitalizations. Although some clinical research and a meta-analysis in patients with acute asthma exacerbation show that nebulized magnesium in combination with standard treatment improves airway function, respiratory rate, and clinical asthma severity when compared with standard treatment alone, it is unclear whether these findings are clinically relevant (90016,113466). Most evidence, including larger clinical trials and meta-analyses, has not shown benefit of adjunct nebulized magnesium for acute asthma in adults or children (60888,90002,96484,104400,105920,113466,114674). Oral magnesium also does not seem to be beneficial. A meta-analysis of small clinical trials in children and adults with asthma shows that taking magnesium supplements orally does not improve lung function or reduce bronchodilator use when compared with control (104404).
• Colorectal cancer. Increasing dietary magnesium intake seems to lower the risk of colon cancer but not rectal cancer. Details: Epidemiological research shows that increased dietary magnesium intake is associated with a reduced risk of colon cancer, but the risk of rectal cancer is not affected (89387,90017,90027,101355).
• Diabetes. Low dietary magnesium may increase the risk of developing type 2 diabetes, but evidence on the use of supplements for treating type 2 diabetes is conflicting. Details: Higher dietary magnesium intake is associated with lower fasting insulin concentrations and a reduced risk of developing type 2 diabetes in adults and obese children (13369,15548,96473,97486,98294,103736,105918,106920). In people with existing type 2 diabetes, hypomagnesemia is found in 25% to 38% of patients, especially in those with poorly controlled diabetes (1172). Population research in adults with type 2 diabetes also shows that a dietary magnesium intake of less than 250 mg daily is associated with a 56% higher risk of mortality. Preliminary subgroup analyses suggest that the risk of mortality is higher in those with glycated hemoglobin (HbA1C) levels above 7% (110051). A meta-analysis of small, heterogeneous clinical studies in adults with type 2 diabetes suggests that magnesium may modestly reduce HbA1C in patients with hypomagnesemia, but not in patients with normal magnesium levels, when compared with control (105075). Individual clinical studies using magnesium supplements in patients with type 2 diabetes or insulin resistance have shown mixed results. Some research suggests magnesium supplements can decrease fasting blood glucose and improve insulin sensitivity, as well as reduce the risk of developing diabetes in high-risk patients (10664,12582,13376,60854,99313,106920), but other research shows no effect (1171,1172,13379,13380,112780). Discrepancies in these findings might reflect differences in magnesium salts and doses used, or differences in baseline magnesium status in study subjects.
• Hypercholesterolemia. Magnesium may help improve lipid levels by a small amount in people with this condition. Details: There is some evidence that taking magnesium oxide 1 gram orally daily for 6 weeks can produce small decreases in low-density lipoprotein (LDL) and total cholesterol levels, and small increases in high-density lipoprotein (HDL) levels in patients with hypercholesterolemia. However, magnesium does not seem to improve lipoprotein (a) levels (1193). Magnesium may also lower triglycerides in people with hypertriglyceridemia (97494).
• Metabolic syndrome. Low dietary and serum levels of magnesium seem to be associated with the development of metabolic syndrome. Details: Higher magnesium intake from diet and supplements is associated with a 27% lower risk of developing metabolic syndrome in healthy females (13371) and a 31% lower risk in healthy young adults (14304). Additional epidemiological research suggests that people with low serum magnesium levels are 6-7 times more likely to have metabolic syndrome than people with normal magnesium levels (13372). In a population analysis of over 6000 individuals without metabolic syndrome at baseline, the risk of developing this condition over a 6-year follow-up period was reduced by 16% in the highest quintile of dietary magnesium intake (median intake 371 mg daily) when compared with the lowest quintile (median intake 203 mg daily). Some, but not all, research suggests that the hazard ratio for metabolic syndrome in relation to magnesium intake may be U-shaped, with higher risk at intakes below about 150 mg daily and above 600 mg daily (108963). A combination of magnesium 20 mEq daily and potassium 40 mEq daily (magnesium potassium citrate) taken orally for 16 weeks reverses metabolic side effects of chlorthalidone, such as increased fasting plasma glucose and hypokalemia, more effectively than potassium chloride 40 mEq daily alone (112932).
• Osteoporosis. Increased dietary and supplemental magnesium intake seems to increase bone mineral density and decrease bone loss in postmenopausal patients. Details: Preliminary clinical research shows that taking magnesium hydroxide orally, 300-1800 mg daily for 6 months, then 600 mg daily for 18 months, or magnesium citrate orally 1830 mg daily for 30 days, might reduce bone loss and bone turnover in postmenopausal patients with osteoporosis (9104,60928). Some epidemiological research also suggests that magnesium intake is related to increased bone mineral density (12501,12502,12503,12504,90014), although not all studies have found an association (12505,98286).
• Postoperative pain. Injectable magnesium has been used with promising results for reducing pain and the need for other analgesics postoperatively. Details: A meta-analysis of 25 clinical trials shows that intravenous (IV) magnesium sulfate, 5-50 mg/kg bolus followed by a continuous infusion of 6 mg/kg or 500 mg hourly during surgery, seems to reduce the 24-hour postoperative use of IV morphine by 24% when compared with placebo (19968). Adding IV magnesium sulfate 3.7-5.5 grams to patient-controlled analgesia for 24 hours after surgery has also been used (19968). Additionally, meta-analyses support that adjunctive IV or intrathecal administration of magnesium reduces post-operative pain scores, improves pain relief and sensory nerve block, and decreases the need for other analgesics, when compared with control (89390,90012,90015,98287,103728,114676,114677,114678). However, some data are conflicting. In a meta-analysis of 7 trials, IV magnesium was not associated with lower pain scores over the first 48 hours postoperatively. The reasons for these discrepant findings are unclear but may be explained by differences in magnesium regimens, anesthesia protocols, and surgical populations studied. Additionally, IV magnesium appears to be less effective than dexmedetomidine (105082). Two moderate-sized clinical studies in patients undergoing total knee arthroplasty in China show that adding magnesium sulfate 2.5 mg/mL to the periarticular infiltration analgesia (PIA) cocktail or administering IV magnesium sulfate 40 mg/kg before anesthesia induction then as a 15 mg/kg infusion during surgery reduces pain scores, increases comfort levels, limits and delays the use of postoperative opioids, prolongs analgesia, and reduces markers of inflammation when compared with the usual PIA cocktail or control (111181,113677). Administering magnesium intravenously also seems to be helpful for pain control after hysterectomy. A 3-gram IV bolus of magnesium sulfate followed by an infusion of 0.5 grams per hour for 20 hours has been used. Lower doses were not effective (6848). In males undergoing laparoscopic radical resection for gastrointestinal cancer, administering IV magnesium intraoperatively, as a loading dose of 40 mg/kg followed by 15 mg/kg/hour through the end of surgery, reduces postoperative catheter-related bladder discomfort and analgesic requirements, when compared with placebo (112783). However, IV magnesium might not alleviate postoperative pain in children. Two small clinical studies show that administering a magnesium IV infusion does not reduce pain when compared with saline in children after tonsillectomy or after elective strabismus surgery (98282,105077).
• Premenstrual syndrome (PMS). Taking magnesium orally seems to relieve symptoms of PMS. Details: There is some evidence that magnesium supplementation can improve symptoms, including mood changes and fluid retention, in some patients with PMS (1187,1188,6847). Doses used include magnesium oxide 333 mg daily for 2 menstrual cycles, or magnesium pyrrolidone carboxylic acid equivalent to 360 mg elemental magnesium three times daily, from the 15th day of the menstrual cycle until onset of menstrual flow (1187,1188). Taking magnesium orally in a dose of 360 mg (elemental magnesium) three times daily for 2 months seems to prevent premenstrual migraine (1186,6847). A combination of magnesium 200 mg daily plus vitamin B6 50 mg daily seems to reduce anxiety-related premenstrual symptoms, including nervous tension, mood swings, irritability, and anxiety, when compared with placebo (8555).
• Vasospastic angina. Intravenous magnesium seems to prevent coronary spasm in patients with this condition. Details: Clinical research shows that administration of intravenous magnesium sulfate 65 mg/kg infused over 20 minutes dilates coronary arteries and suppresses acetylcholine-induced coronary spasms when compared with infusion of a dextrose solution in patients with vasospastic angina (8091).

POSSIBLY INEFFECTIVE

• Altitude sickness. Taking magnesium citrate orally does not seem to reduce acute altitude sickness risk. Details: Clinical research shows that taking magnesium citrate 1200 mg daily orally in three divided doses, beginning 3 days prior to mountain ascent and continuing until mountain descent, does not reduce the risk of acute altitude sickness when compared with placebo (60801).
• Athletic performance. Taking magnesium orally does not seem to improve energy or endurance during athletic activity. Details: Most evidence suggests that taking magnesium orally doesn't increase energy and endurance during athletic activity. Magnesium oxide, aspartate, and orotate salts do not seem to improve exercise performance when used alone or in combination with potassium, vitamin B6, or zinc (2825,2826,2828,2829,2830,60751,113655).
• Bronchiolitis. Intravenous or nebulized magnesium is not beneficial in infants with this condition. Details: Clinical research shows that administering a single IV dose of magnesium sulfate 100 mg/kg to infants with acute bronchiolitis does not improve, and may actually worsen, symptoms when compared with placebo (97482). A clinical study in infants with moderate to severe bronchiolitis shows that adding nebulized magnesium sulfate 40 mg/kg to nebulized epinephrine does not reduce hospital stay or the need for ventilator or oxygen support when compared with epinephrine alone (99317). Oral magnesium has not been evaluated for this use.
• Chemotherapy-induced peripheral neuropathy. Research on the effects of intravenous infusions of magnesium and calcium for preventing oxaliplatin neurotoxicity are inconsistent, but higher quality studies seem to show no benefit. Details: Pooled analyses of cohort studies and clinical trials show that calcium and magnesium infusions can decrease the incidence of severe oxaliplatin-induced neurotoxicity (90028,90029,90031). However, when only clinical trials are considered, the infusions do not appear to be helpful (90005,90029,90031,96474,96479).
• Complex regional pain syndrome. Intravenous magnesium is not beneficial in complex regional pain syndrome type 1. Details: Clinical research shows that receiving magnesium sulfate 70 mg/kg intravenously at the rate of 25 mL/hour for 4 hours each day for 5 days does not improve pain or level of impairment when compared with placebo in patients with chronic complex regional pain syndrome type 1 (89395).
• Emergence delirium. The majority of small clinical studies in adults and children undergoing various surgeries suggest that intravenous (IV) magnesium doesn't reduce the risk of emergence delirium. However, most clinical studies in adults suggest that IV magnesium reduces emergence agitation. Details: A small clinical study in adults undergoing surgery for endovascular aortic aneurysm repair shows that administering IV magnesium 30 mg/kg as a loading dose, followed by a 10 mg/kg/hour infusion for the duration of surgery, does not improve agitation or delirium scores when compared with administering saline (111182). Similarly, a small clinical study in children ages 2-5 years undergoing elective strabismus surgery shows that administering IV magnesium during anesthesia does not seem to prevent the occurrence of emergence delirium when compared with administering saline (105077). In a meta-analysis of 8 clinical trials in children aged 2-16 years undergoing general anesthesia for oral or ophthalmic surgery, giving IV magnesium as a 30 mg/kg loading dose followed by a 10 mg/kg/hour infusion, or as a single dose of 15-30 mg/kg, does not reduce emergence delirium scores, and may actually prolong emergence times (108729). However, there is some conflicting evidence. In patients undergoing radical mastectomy, giving intraoperative magnesium sulfate 30mg/kg over 1 hour, followed by 10 mg/kg/hour until the end of surgery, reduces emergence agitation (odds ratio 0.26) when compared with placebo (112781).
• Menopausal symptoms. Oral magnesium oxide does not seem to be beneficial for menopausal hot flashes. Details: A small, low quality study in postmenopausal patients with a history of breast cancer shows that taking magnesium oxide 400-800 mg orally daily reduces hot flashes when compared with baseline (102454). However, a larger, higher quality clinical study using magnesium oxide 800-1200 mg daily did not show any benefit when compared with placebo (98290).
• Muscle cramps. Oral magnesium does not seem to improve muscle cramp frequency or intensity. Details: Meta-analyses of small clinical trials show that magnesium supplementation for 3-6 weeks does not decrease the frequency or intensity of skeletal muscle cramps, whether the cramps are idiopathic or due to liver cirrhosis or pregnancy, when compared with placebo (90022,104395).
• Sickle cell disease. Intravenous magnesium does not add any benefit to standard therapy for sickle cell disease in children. Details: Clinical research shows that giving magnesium sulfate 40-100 mg/kg (maximum of 2 grams per dose) intravenously every hour for 6-8 doses as an adjunct to standard therapy does not decrease hospital stay, pain, or opioid use, or improve quality of life, when compared with standard therapy and placebo in children with sickle cell disease (89399,98283,101356). Oral magnesium has not been evaluated for this purpose.
• Stillbirth. Magnesium administered during pregnancy does not reduce stillbirth risk. Details: A meta-analysis of clinical research shows that magnesium supplementation does not significantly decrease the risk of stillbirths when administered during pregnancy (60925,60978).
• Tetanus. Intravenous magnesium sulfate does not seem to improve outcomes in patients with this condition. Details: A meta-analysis of clinical research shows that intravenous magnesium sulfate does not reduce mortality when compared with placebo or diazepam in patients with tetanus (61020). While some research shows that magnesium reduces the duration of hospitalization and the need for ventilation when compared with diazepam (61170), magnesium does not seem to improve these outcomes when compared with placebo (60860).
• Traumatic brain injury (TBI). Magnesium does not improve clinical outcomes in patients with moderate to severe TBI. Its effect in patients with concussions is unclear. Details: A meta-analysis of four clinical trials shows that treatment with magnesium does not significantly improve neurological outcomes or reduce the risk of mortality when compared with placebo in patients with moderate to severe TBI (60905). A small observational cohort study in adolescents with concussions has found that adding oral magnesium 400 mg twice daily for 5 days to standard treatment with acetaminophen and ondansetron is associated with a trend toward reduced symptom severity when compared with standard treatment alone (104401). The validity of this study is limited by its observational nature and small cohort size.

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Alcohol use disorder. Intravenous magnesium does not seem to help reduce symptoms of alcohol withdrawal but may reduce the duration of alcoholic delirium. Details: Preliminary clinical research shows that administration of four intramuscular injections of magnesium sulfate 2 grams at 6-hour intervals does not reduce symptoms of alcohol withdrawal when compared with saline (61063). A small observational study in patients with alcoholic delirium has found that administering magnesium sulfate IV 50 mg/kg every 8 hours, in addition to usual sedation, is associated with a reduction of delirium by approximately 2 days, or 4 days when given every 12 hours in addition to dexmedetomidine, when compared with usual sedation alone (111180). However, half of patients had hypomagnesemia at baseline; it is unclear if effects would be similar for patients with normal magnesium levels. Oral magnesium has not been evaluated for this purpose.
• Allergic rhinitis (hay fever). Although there has been interest in using oral magnesium for allergic rhinitis, there is insufficient reliable information about the clinical effects of magnesium for this purpose.
• Attention deficit-hyperactivity disorder (ADHD). It is unclear if oral magnesium is beneficial in children with ADHD. Details: Children with ADHD seem to have lower magnesium levels in their blood and hair (9969,100262,100263). A small clinical study in children aged 7-12 years with ADHD and magnesium deficiency shows that taking magnesium aspartate and lactate 6 mg/kg daily for 6 months might improve hyperactivity and magnesium levels when compared with control (1189). Another small clinical study in children with ADHD but without magnesium deficiency shows that taking magnesium 6 mg/kg daily along with vitamin D 50,000 IU weekly for 8 weeks may modestly improve emotional problems, but not inattention or hyperactivity, as measured on the strength and difficulties questionnaire (SDQ), when compared with placebo (105914).
• Back pain. It is unclear if oral or intravenous magnesium is beneficial for acute or chronic back pain in adults. Details: One open-label clinical study in adults with acute low-back pain shows that taking magnesium 365 mg once daily in addition to taking etodolac 400 mg twice daily for 10 days does not further reduce pain when compared with taking etodolac alone (105913). Magnesium has also been tried for chronic back pain. A small clinical study in patients with chronic low-back pain shows that receiving magnesium sulfate 1 gram in 250 mL normal saline intravenously every 4 hours for 2 weeks, followed by magnesium gluconate 100 mg and magnesium oxide 400 mg by mouth daily for 4 weeks, reduces pain severity when compared with placebo (90035). It is unclear if oral magnesium used alone is beneficial.
• Bariatric surgery complications. It is unclear if oral magnesium supplementation improves metabolic parameters after bariatric surgery. Details: A retrospective study of over 3000 post-bariatric surgery patients suggests that those who take oral magnesium supplements providing 100-450 mg elemental magnesium daily may have improved metabolic parameters over 4 years of follow-up. When patients taking magnesium supplements were compared with those not taking supplements, 11% and 18% had type 2 diabetes, respectively, 30% and 42% had hypertension, respectively, and 16% and 23% had elevated low-density lipoprotein (LDL) cholesterol levels, respectively. For patients with hypomagnesemia at baseline, supplementation seemed to result in greater benefits (108968).
• Bipolar disorder. Taking magnesium orally might improve manic symptoms in some people with bipolar disorder; however, it is unclear how it compares to current standard of care. Details: One preliminary clinical study shows that magnesium 40 mEq daily (Magnesiocard) for 32 weeks has similar effects to lithium in up to 50% of patients treated for rapid cycling bipolar affective disorder (61022). Another preliminary clinical study shows that magnesium oxide 375 mg orally daily plus verapamil 80 mg taken four times daily reduces manic symptoms more effectively than verapamil alone in patients with mania (60742).
• Cancer-related neuropathic pain. It is unclear if intravenous magnesium is beneficial for this condition. Details: Single 500 mg to 1 gram doses of magnesium sulfate seem to relieve neuropathic pain for up to four hours when compared to baseline (6846). The validity of this finding is limited by the lack of a comparator group.
• Cardiac arrest. Intravenous magnesium does not seem to be helpful in cardiac arrest; however, the risk of sudden cardiac death seems to be inversely correlated to higher plasma magnesium levels or dietary intake. It is unclear if magnesium supplementation is associated with similar risk reduction. Details: Administering magnesium intravenously doesn't seem to improve successful resuscitation in people with cardiac arrest (1190). However, higher plasma magnesium levels and higher dietary magnesium intake might reduce the risk of sudden cardiac death, possibly by protecting against fatal ventricular arrhythmias. In the Nurses' Health Study, the risk of sudden cardiac death was 77% lower in females with the highest quartile of plasma magnesium levels when compared with the lowest quartile. Also, the risk was 37% lower in females with the highest quartile of dietary magnesium intake when compared with the lowest quartile (17132).
• Cardiovascular disease (CVD). Evidence regarding the effect of dietary magnesium on CVD risk is conflicting. Details: Epidemiological research in some populations shows that increased dietary magnesium intake is associated with decreased mortality due to strokes, coronary heart disease, ischemic heart disease, and heart failure, but other epidemiological research does not show any effect on these risks (89391,90003,90009,90030,90036,103735). Reasons for the discrepancies may be related to serum levels of magnesium at baseline, risk of cardiovascular disease at baseline, use of concomitant medications such as diuretics, or the presence of concomitant conditions such as kidney dysfunction. A population analysis conducted in Denmark has found that magnesium intake from drinking water may be associated with cardiovascular mortality. The overall risk of cardiovascular death and death due to stroke was reduced by 4% in the lowest 3 quintiles of intake when compared with the highest quintile. However, the risk of death due to acute myocardial infarction was increased by 22% in the lowest quintile when compared with the highest (108726). The relevance of these results is unclear, given that the main dietary source of magnesium is food rather than drinking water.
• Chronic fatigue syndrome (CFS). Limited evidence suggests that magnesium may help improve CFS symptoms, but this is controversial. Details: In people with low red blood cell magnesium, there is some evidence that intramuscular injections of 1 gram magnesium sulfate given once weekly for 6 weeks might improve CFS symptoms (7556). However, there is additional evidence that most patients with CFS have normal magnesium stores, and measurement of red cell magnesium is a poor indicator of total magnesium stores (7557,8084,8085,8086,8087).
• Chemotherapy-induced leukopenia. It is unclear if oral magnesium is beneficial in pediatric patients at risk for cisplatin-induced febrile neutropenia. Details: A small clinical study in children with solid tumors aged 9 years and older shows that taking magnesium 250 mg daily while receiving cisplatin-based chemotherapy reduces febrile neutropenia by 47% and septic shock by 57% when compared with not receiving magnesium. Results from this study suggest that four pediatric patients need to take oral magnesium to avoid one case of febrile neutropenia (104394).
• Chemotherapy-induced nephrotoxicity. It is unclear if intravenous magnesium is beneficial for chemotherapy-induced nephrotoxicity. Details: A meta-analysis of several lower quality clinical studies in adults in Japan with cancer receiving cisplatin shows that pretreatment with intravenous magnesium sulfate 5 to 20 mEq reduces the odds of chemotherapy-induced nephrotoxicity in a dose-dependent manner when compared to standard hydration therapy (115726). The validity of these findings is limited by heterogenous methods between clinical trials, including types of cancer, definitions of nephrotoxicity, and use of other nephroprotective therapies.
• Chronic obstructive pulmonary disease (COPD). Intravenous, but not nebulized, magnesium may be helpful in acute exacerbations of COPD. Details: Administering magnesium sulfate intravenously, 1.2-2.5 grams over 20 minutes, might be helpful for treating acute exacerbations of COPD (1208,6844,103733). Also, giving magnesium sulfate 2 grams intravenously seems to improve exercise capacity when compared with placebo (89384). A meta-analysis of studies using intravenous magnesium sulfate for COPD exacerbations shows that it reduces hospital admission and mean length of stay and improves dyspnea scores when compared with placebo. Based on the relative risk identified in the included studies, seven patients would need to receive intravenous magnesium to prevent one hospitalization. However, intravenous magnesium sulfate does not change the need for non-invasive ventilation and the available research did not evaluate intensive care unit (ICU) admission (108967). Nebulized magnesium has also been evaluated. In patients experiencing a COPD exacerbation, clinical research shows that administering nebulized magnesium sulfate with albuterol three times at 30-minute intervals does not improve pulmonary function as measured by the forced expiratory volume in 1 second (FEV1) when compared with placebo (89393). Also, a meta-analysis of a small number of low-quality studies shows that nebulized magnesium does not reduce hospital admission or the need for ventilatory support, although it might modestly improve dyspnea scores and reduce ICU admissions, when compared with placebo (108967).
• Cluster headache. It is unclear if a single intravenous dose of magnesium sulfate is beneficial for cluster headaches. Details: Administering magnesium sulfate intravenously, 1 gram over 5 minutes, seems to improve cluster headaches when compared with baseline(1184). The validity of this finding is limited by the lack of a comparator group.
• Cognitive impairment. It is unclear if oral magnesium is beneficial for cognitive impairment. Details: A large observational study in adults with end-stage renal disease on hemodialysis suggests that serum magnesium levels of 20.2-22.3 mg/dL are associated with the lowest odds of mild cognitive impairment, while serum magnesium levels below and above that range of values are associated with increased odds of mild cognitive impairment (111695).
• Coronary heart disease (CHD). It is unclear if magnesium supplementation is beneficial for CHD. Details: Clinical research shows that magnesium oxide 800-1200 mg daily for 3 months reduces platelet-dependent thrombosis by 35% when compared with placebo in patients with CHD (60759). It is unclear if this effect improves clinical outcomes. The effect of magnesium supplementation on coronary artery calcium has also been studied. A meta-analysis of 3 clinical studies in 196 patients with chronic kidney disease (CKD) shows that taking magnesium or increasing the concentration of magnesium in dialysate does not improve coronary artery calcification (CAC) scores when compared with standard therapy. However, magnesium reduced carotid intima-media thickness (111179). Similarly, a large clinical study in patients with CKD shows that taking slow-release magnesium hydroxide (Mablet, Denmark) 360 mg twice daily for 12 months does not slow the progression of CAC scores when compared with placebo (111178). This study may not have been adequately powered to detect a difference between groups.
• Coronavirus disease 2019 (COVID-19). It is unclear if oral magnesium is beneficial for COVID-19. Details: A small clinical study in patients hospitalized with moderate COVID-19 shows that taking magnesium 300 mg daily for the duration of hospitalization reduces the number of patients requiring oxygen therapy but not the duration of hospital stay when compared with placebo (114680).
• Depression. It is unclear if magnesium is beneficial for the treatment or prevention of depression in adults. Details: Some population research shows that dietary intake of elemental magnesium between 76-360 mg daily is associated with a reduced risk of depression, but there was no association with greater amounts of magnesium, and other population research shows no association at any intake level (96480,98289). For treatment of mild to moderate depression, one preliminary clinical study shows that taking magnesium chloride 2 grams orally daily for 6 weeks reduces depression scores by 56% and anxiety scores by about 52% when compared to baseline (96477). The validity of these findings is limited by the lack of a comparator group. However, a small clinical study in adults with recurrent depression shows that taking magnesium aspartate 120 mg daily for 8 weeks, along with fluoxetine, does not improve depression scores when compared with patients taking fluoxetine and placebo (111185). Similarly, a very small crossover clinical study in adults with mild or moderate treatment-resistant depression shows that administering a single dose of IV magnesium sulfate 4 grams does not improve depression scores when compared with an infusion of 5% dextrose (96481). However, scores were evaluated 24 hours post-infusion which may be too soon to detect improvement. Guidelines from The World Federation of Societies of Biological Psychiatry (WFSBP) and Canadian Network for Mood and Anxiety Treatments (CANMAT) Taskforce state that elemental magnesium in doses of 100-400 mg is not recommended for adjunctive or monotherapy use in patients with depression (110318).
• Diabetic foot ulcers. Oral magnesium has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in patients with grade 3 diabetic foot ulcers shows that taking magnesium oxide 250 mg plus vitamin E 400 IU daily for 12 weeks modestly reduces ulcer size when compared with placebo (101436). It is unclear if this effect is due to magnesium, vitamin E, or the combination.
• Exercise-induced muscle soreness. It is unclear if oral magnesium reduces muscle soreness in adults after resistance training. Details: A very small study in healthy adults, ages 19-23, shows that taking magnesium glycinate 350 mg daily for 10 days seems to reduce muscle soreness after bench press exercise when compared with placebo (104399).
• Fetal and premature infant mortality. It is unclear if antenatal intravenous (IV) magnesium sulfate administration reduces the risk of fetal and premature infant mortality. Details: Two meta-analyses of up to 7 clinical studies in patients at risk of preterm birth shows that antenatal IV magnesium sulfate administration does not reduce the risk of fetal or neonatal death when compared with placebo (114675,114681).
• Fibromyalgia. It is unclear if oral magnesium is beneficial for this condition. Details: A small clinical study shows that taking magnesium chloride orally 100 mg once daily for one month reduces mild to moderate, but not severe, stress associated with fibromyalgia when compared with placebo. It also reduces pain levels, but not to a clinically significant extent, and it does not affect sleep, fatigue, or quality of life (108964). Another small clinical study shows that taking magnesium citrate 300 mg daily for 8 weeks improves some symptoms of fibromyalgia, such as number of tender points and depression, when compared to baseline (89385). The validity of this finding is limited by the lack of a comparator group. A small clinical study shows that taking a combination of magnesium hydroxide and malic acid (Super Malic tablets) orally decreases fibromyalgia-related pain and tenderness in some patients when compared with placebo (3262). It is unclear if this effect is due to magnesium, malic acid, or the combination.
• Fractures. Population research suggests that higher intakes of magnesium may reduce fracture risk. Details: Observational research has found that higher dietary and supplemental magnesium intake is associated with a 34% lower odds of fracture when compared with lower magnesium intake (101395).
• Gastric cancer. Population research suggests that higher intakes of magnesium may reduce gastric cancer risk. Details: Observational research has found that higher dietary and supplemental magnesium intake is not associated with a reduced risk for gastric cancer when compared with lower intake (103730).
• Hearing loss. Oral magnesium may prevent and improve hearing loss due to environmental factors or loud noises. Details: Clinical research in healthy military recruits shows that taking magnesium aspartate 167 mg daily for 2 months prevents hearing loss from exposure to loud noises during basic military training when compared with placebo (1205). Also, in patients with acute-onset hearing loss that was not caused by environmental factors, taking magnesium aspartate 167 mg daily for 8 weeks seems to improve hearing loss when compared with placebo (60813).
• Hypertension. Oral magnesium supplementation may modestly reduce blood pressure, although these changes are not likely to be considered clinically significant. Details: Most research shows that taking oral magnesium supplements in daily doses that are at least as high as the Recommended Dietary Allowance (RDA) for adults and up to 1000 mg daily can lower diastolic blood pressure by about 2 mmHg in adults with or without hypertension (1192,1199,9465,15165,18111,96482). Significantly lower doses do not seem to have this effect (1180,1195,1197,8098). The effect of magnesium on systolic blood pressure is conflicting. Two meta-analyses shows that taking magnesium 212-970 mg daily does not lower systolic blood pressure in patients with or without hypertension (15165,115728). However, additional meta-analyses show that taking magnesium 120-970 mg daily can lower systolic blood pressure in a dose-dependent manner by about 2-4 mmHg in patients with or without hypertension (18111,96482). The reasons for these discrepant findings are unclear but may be due to heterogenous methods, including dose and duration among clinical studies. In 2022, the US Food and Drug Administration (FDA) approved a qualified health claim stating that inconsistent and inconclusive evidence suggests that diets with adequate magnesium may reduce the risk of high blood pressure. Products bearing this claim must provide at least 84 mg of magnesium daily, but no more than 350 mg daily (107451).
• Hypokalemia. It is unclear if intravenous or oral magnesium is beneficial for hypokalemia in patients with normal magnesium levels. Details: A preliminary retrospective observational study in patients with hypokalemia and unknown serum magnesium levels has found that administering oral or intravenous magnesium is not associated with improved time to normalization of serum potassium levels when compared with no magnesium treatment (110049). However, hypokalemia with concurrent hypomagnesemia can impede potassium repletion and exacerbate hypokalemia-induced rhythm disturbances. Standard of care in patients with hypokalemia and known hypomagnesemia includes prompt treatment with magnesium (110063).
• Impaired glucose tolerance (prediabetes). It is unclear if oral magnesium is beneficial for prediabetes. Details: Preliminary clinical research in patients with prediabetes shows that taking magnesium oxide 250 mg orally daily for 12 weeks does not improve fasting blood glucose levels, insulin resistance, or glycated hemoglobin (HbA1C) levels when compared with placebo. Taking magnesium also did not affect blood pressure, body weight, triglyceride levels, or low-density lipoprotein cholesterol levels; however, it did modestly improve high-density lipoprotein cholesterol levels (110053).
• Insomnia. Oral magnesium may modestly improve sleep complaints in adults, but evidence is conflicting. Details: A meta-analysis of two small clinical studies in healthy older adults with or without insomnia suggests that taking magnesium reduces the time to fall asleep by an average of 17 minutes when compared with placebo (105917). However, it does not increase the time spent asleep. Also, these findings are limited by imprecision and a high risk of bias. Studies included in the analysis used elemental magnesium 500-729 mg daily (as magnesium oxide) for up to 8 weeks (102458,105917). Another small clinical study in patients with poor sleep quality and low magnesium status shows that taking elemental magnesium 320 mg (as magnesium citrate) in divided doses daily for 7 weeks does not improve sleep quality, as measured by the Pittsburgh Sleep Quality Index (PSQI), when compared with a sodium citrate placebo (102456). Magnesium has also been evaluated in combination with other ingredients. A very small crossover clinical study in patients aged 18-40 years without a sleep disorder shows that taking a combination of magnesium 300 mg, L-tryptophan 1000 mg, glycine 3000 mg, tart cherry 220 mg, and theanine 200 mg for 3 days reduces the time to fall asleep by about 24 minutes, increases total time asleep by about 22 minutes, and improves sleep efficiency, but does not improve the total time in bed or wakefulness after falling asleep when compared with cellulose placebo (111184). Another small crossover clinical study in adults with sleep disturbances shows that taking a combination of magnesium 200 mg and melatonin nightly for 4 weeks improves sleep quality, as measured by the PSQI, reduces the length of time it takes to fall asleep by about 17 minutes, and improves some other measures of sleep, such as sleep efficiency and number of awakenings, when compared with placebo. However, despite these improvements, overall sleep quality was still categorized as poor after the intervention (113670). It is unclear if these effects are due to magnesium, other ingredients, or the combination.
• Intraventricular hemorrhage. It is unclear if antenatal intravenous (IV) magnesium sulfate can reduce the risk for intraventricular hemorrhage in neonates. Details: A meta-analysis of clinical research in premature infants shows that if the mother received antenatal intravenous magnesium sulfate, the infant had a non-significant trend toward a reduced risk of intraventricular hemorrhage when compared with infants whose mothers received placebo (103727). This analysis may have been insufficiently powered to detect a difference between groups. Another meta-analysis of up to 6 clinical studies, some of which are included in the previously referenced meta-analysis, in patients at risk of preterm birth shows that maternal antenatal (IV) magnesium sulfate administration does not reduce the risk of intraventricular hemorrhage, but does reduce the risk of severe intraventricular hemorrhage by about 24% when compared with placebo (114681).
• Kidney stones (nephrolithiasis). Taking magnesium orally may prevent the recurrence of kidney stones, although evidence is conflicting. Details: Prophylactic treatment with magnesium hydroxide, 200 mg twice daily for one year, followed by 500 mg daily for another year, might decrease the recurrence rate of calcium stone formation (2007). However, magnesium oxide does not seem to benefit patients considered to be recurrent calcium stone formers when compared with placebo, no treatment, or chlorthalidone (8097,38501,61199). Magnesium oxide 300 mg in combination with vitamin B6 10 mg daily seems to decrease urinary oxalate levels in people with hyperoxaluria who have previously had kidney stones (1201), but it is unclear if this effect translates into a reduced incidence of kidney stones.
• Liver cancer. Increased dietary magnesium intake is linked with a lower risk of liver cancer. Details: Observational research in retired older Americans has found that higher dietary magnesium intake is associated with a 35% lower risk of liver cancer when compared with lower intake. This association was especially strong in persons who were moderate or heavy alcohol users (105080).
• Lung cancer. Supplemental or dietary magnesium intake does not seem to reduce the risk of lung cancer. Details: A large epidemiological cancer screening trial with a mean follow-up of over 12 years suggests there is no association between dietary or supplemental magnesium intake and the risk of lung cancer. However, dietary magnesium seems to play an important yet unclear role in lung cancer prevention when taken as part of the diet with alpha-carotene, vitamin C, vitamin E, lycopene, selenium, lutein, and zeaxanthin (112096).
• Migraine headache. Oral magnesium may help prevent migraine in some adults and children. Also, intravenous magnesium may help treat migraine in adults, but evidence is conflicting. Details: A meta-analysis of 4 low-quality clinical studies, in adults with migraine shows that magnesium 122-600 mg daily for 4-16 weeks modestly reduces migraine frequency and severity when compared with placebo(115730). However, clinical significance is unclear, and the validity of these findings is limited by heterogeneous methods between clinical trials, including type of magnesium formulation and dose, patient population, and duration. In contrast, one small clinical study shows that taking magnesium does not reduce migraine frequency and severity by at least 50% in adults when compared with placebo (10661). Limited evidence suggests that adding oral magnesium to conventional treatment may also be beneficial. A clinical study in adults with migraine living in Iran shows that taking magnesium oxide 250 mg twice daily in addition to sodium valproate 200 mg twice daily for 12 weeks modestly reduces severity and duration of migraine, but not migraine frequency, when compared with taking sodium valproate alone (105915). It is unclear if these improvements would be considered clinically significant. For treatment of migraine, some adults with normal magnesium levels respond to intravenous (IV) magnesium sulfate 1 gram over 5 minutes, but most patients who benefit have low magnesium levels at baseline (1185,6844). Effects of IV magnesium in patients with unknown magnesium levels are conflicting. Some preliminary clinical research shows that magnesium 1-2 grams IV alleviates acute migraine for up to 2 hours, but other research has found no benefit (89388,97493,98285). In children, treatment with magnesium oxide orally 15 mg/kg daily in 3 divided doses for up to 16 weeks reduces the frequency and severity of migraine headaches when compared with placebo (10663). However, adding magnesium sulfate 400 mg orally daily to ibuprofen or acetaminophen does not further reduce migraine severity in children (89396).
• Miscarriage. Oral magnesium has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in pregnant adults with threatened miscarriage between the 6th and 13th week of gestation shows that taking a specific combination product (DAV HA, Lo.Li pharma s.r.l) containing magnesium 450 mg, alpha-lipoic acid, hyaluronic acidvitamin B6, and vitamin D daily in combination with conventional treatment of vaginal progesterone over 2 weeks of observation results in a faster resorption of the subchorionic hematoma and faster decrease of patient-reported vaginal bleeding, abdominal pain, and uterine contractions when compared with vaginal progesterone alone (113893). It is unclear if these effects are due to magnesium, other ingredients, or the combination. Additionally, the validity of these findings is limited by the lack of a placebo in the control group.
• Myocardial infarction (MI). Research on the effects of intravenous or oral magnesium after myocardial infarction are conflicting. Details: Administering magnesium intravenously doesn't seem to reduce mortality after an acute MI (8999,13357,13358,13359,13360,19990,60872,61082), although there is some conflicting evidence from a meta-analysis of clinical research that shows that intravenous magnesium sulfate may reduce short-term mortality by 55% when compared with placebo (60795,60895). Clinical research with oral magnesium supplementation has found no benefit (1198,6844).
• Neonatal encephalopathy. Intravenous magnesium may improve short-term outcomes in neonates with encephalopathy. Details: A meta-analysis of clinical research shows that intravenous magnesium may improve short term outcomes of neonatal encephalopathy (hypoxic ischemic encephalopathy, HIE). However, long term outcomes are not affected (90025).
• Nocturnal leg cramps. It is unclear if oral magnesium is helpful for nocturnal leg cramps. Details: Some clinical research in adults with nocturnal leg cramps shows that taking magnesium oxide 865 mg daily at bedtime for 4 weeks does not reduce the frequency of leg cramping episodes when compared with placebo (96478). However, four weeks may be too short a time to see a benefit. In other clinical research, taking oral magnesium oxide monohydrate 226mg daily at bedtime for 60 days reduces the frequency of leg cramps when compared with placebo. This reduction was not seen after 30 days. Magnesium also reduced cramp duration and improved sleep quality, but did not affect pain scores, at 60 days when compared with placebo (106919).
• Nonalcoholic fatty liver disease (NAFLD). Oral magnesium hydroxide has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in adults with NAFLD shows that taking magnesium hydroxide 150 mg and L-carnitine 2000 mg daily for 16 weeks does not improve liver stiffness scores when compared with baseline or controls who took placebo for 8 weeks followed by this magnesium and L- carnitine combination for 8 weeks. Taking magnesium and L-carnitine also did not improve levels of aspartate aminotransferase (AST) or alanine transaminase (ALT) when compared to baseline (111177).
• Obesity. Evidence on the use of magnesium for weight loss in obese patients is conflicting; any benefit is likely small at best. Details: A meta-analysis of 7 clinical studies in obese patients shows that taking magnesium reduces body mass index (BMI) by 0.3 when compared with control (103723). Another meta-analysis of 7 studies in obese patients shows that while magnesium supplementation does not reduce weight, it reduces waist circumference by 2 cm when compared with placebo (103729). Interestingly, subgroup analyses did not find that the dose of magnesium or baseline magnesium levels impacted effectiveness. One subgroup analysis found that magnesium supplementation lasting 12 weeks or less seemed to be more beneficial for obesity than supplementation lasting longer than 12 weeks (103723).
• Overall mortality. It is unclear if oral or IV magnesium reduces the risk of overall mortality. Details: A meta-analysis of heterogeneous observational studies has found that increased dietary magnesium intake, but not supplemental magnesium intake, is associated with a modestly reduced risk of overall mortality (105073). A meta-analysis of 3 small, low-quality clinical studies in ICU patients shows that administering IV magnesium 24-30 mmol or as a target-directed dose for 3 days reduces overall mortality when compared with patients who did not receive magnesium (111290). However, some studies included patients with hypomagnesemia; it is unclear if effects would be similar for patients with normal levels of magnesium.
• Osteoarthritis. Population research has not found a link between magnesium intake and osteoarthritis risk. Details: Observational research has found that dietary and supplemental magnesium intake is not associated with the risk of developing osteoarthritis (101395).
• Pain (acute). It is unclear if locally injected or intravenous magnesium is helpful for acute pain. Details: Preliminary clinical research in patients with renal colic shows that intravenous (IV) magnesium sulfate, 50 mg/kg infused over 20 minutes, is as effective as IV morphine sulfate 0.1 mg/kg for controlling acute renal pain at 20 minutes after the dose (107367). Magnesium has also been evaluated in a dental procedure. A single-center clinical study in India in adults with irreversible pulpitis requiring a root canal shows that a local injection of 0.2 mL of 10% magnesium sulfate with lidocaine and epinephrine reduces perioperative pain when compared to lidocaine with epinephrine alone (115729).
• Pain (chronic). Population research suggests that higher intakes of magnesium may modestly reduce the risk for chronic pain. Details: A cross-sectional observational study has found that increased magnesium intake is associated with a 7% to 8% reduced risk for chronic pain. The association was found to be stronger in females than in males (103732).
• Parturition. It is unclear if topical magnesium is beneficial for labor duration. Details: A single-center clinical study in Iranian adults shows that applying 10 mL of a 50% magnesium sulfate solution directly to the cervix during the active phase of labor reduces the time to vaginal delivery by approximately 1.5 hours and improves the childbirth experience, as reported by patients, when compared with placebo. However, clinical significance is unclear (115727).
• Perioperative anxiety. It is unclear if oral magnesium is beneficial for perioperative anxiety. Details: Preliminary clinical research in adults undergoing open heart surgery shows that taking magnesium oxide 250 mg orally twice daily during hospitalization moderately improves anxiety and depression scores when compared with no magnesium therapy. Magnesium therapy was held for the 2 days immediately following surgery (110054).
• Physical performance. Oral magnesium may modestly improve physical performance in otherwise healthy, elderly females. Details: Clinical research in otherwise healthy elderly females shows that taking a magnesium oxide supplement (Easymag, Sanofi-Aventis) 900 mg daily for 12 weeks modestly improves walking speed and chair stand speed in elderly females when compared with no treatment (90026).
• Polycystic ovary syndrome (PCOS). It is unclear if oral magnesium is beneficial for improving metabolic indices in patients with PCOS. Details: Two small clinical studies in patients with PCOS show that taking magnesium oxide orally, 250 mg daily for 8 weeks, does not affect insulin resistance, beta-cell function, lipid levels, or insulin sensitivity when compared with placebo (103725,105887). Other clinical research in patients with PCOS shows that taking magnesium oxide orally, 250 mg daily for 10 weeks, improves subjective measures of quality of life, fatigue, and emotional functioning, but not objective measures such as alopecia, abnormal uterine bleeding, or acne, when compared with placebo (108965). A clinical study using a combination of magnesium 250 mg with vitamin E 400 mg daily for 12 weeks shows a modest reduction in insulin resistance, insulin levels, and triglyceride levels, but not other lipid levels, when compared with placebo (100264). It is unclear if these beneficial effects are due to magnesium, vitamin E, or the combination.
• Postoperative nausea and vomiting (PONV). It is unclear if intravenous (IV) magnesium is beneficial for PONV due to mixed results from clinical research. Details: A meta-analysis of 5 clinical studies in adults undergoing surgery with general anesthesia shows that administering IV magnesium sulfate intraoperatively reduces PONV (114676). However, a meta-analysis of 20 clinical studies in adults undergoing surgery with general anesthesia shows that administering IV magnesium perioperatively does not reduce the incidence of PONV (114678). A moderate-sized clinical study conducted in China in older adults undergoing total knee arthroplasty shows that administering intravenous magnesium sulfate 40 mg/kg prior to anesthesia induction then 15 mg/kg during surgery reduces the incidence of postoperative vomiting but not postoperative nausea when compared with control (113677). The reasons for these discrepant findings are unclear but may be explained by differences in magnesium regimens, anesthesia protocols, and surgical populations studied.
• Postoperative recovery. It is unclear if intravenous (IV) magnesium is beneficial for postoperative recovery. Details: A moderate-sized clinical study conducted in China in older adults undergoing total knee arthroplasty shows that administering IV magnesium sulfate 40 mg/kg prior to anesthesia induction then 15 mg/kg during surgery does not reduce extubation time, time spent in the post-anesthesia care unit (PACU), or duration of hospital stay when compared with control (113677). Additionally, a meta-analysis of 3 different clinical studies in adults undergoing surgery with general anesthesia shows that administering IV magnesium intraoperatively does not reduce extubation time (114676).
• Postoperative sleep disturbance. It is unclear if oral magnesium is beneficial for postoperative sleep disturbances. Details: Preliminary clinical research in adults undergoing open heart surgery shows that taking magnesium oxide 250 mg orally twice daily during hospitalization moderately improves sleep scores when compared with no magnesium therapy. Magnesium therapy was held for the 2 days immediately following surgery (110054).
• Postoperative sore throat. It is unclear if topical magnesium sulfate is beneficial for reducing sore throat pain after endotracheal intubation. Details: Preliminary clinical research in patients undergoing endotracheal intubation for surgery shows that using a gargle containing magnesium sulfate 20% with lidocaine, 20 minutes before anesthesia induction, is less effective for reducing sore throat pain than a gargle containing dexmedetomidine and lidocaine (112779). The study did not include a comparison to lidocaine alone.
• Pregnancy-related leg cramps. It is unclear if oral magnesium reduces leg cramps during pregnancy; evidence is conflicting. Details: One small clinical study in patients with pregnancy-related leg cramps shows that taking magnesium bisglycinate chelate 300 mg daily for 4 weeks reduces the frequency and intensity of leg cramps when compared with placebo (99318). A smaller clinical study in this population shows that taking a specific mixture of magnesium lactate and citrate (Nycoplus Magnesium) providing elemental magnesium 120 mg in the morning and 240 mg in the evening for 3 weeks reduces the frequency of cramps when compared with placebo (1194). However, not all research agrees. One small clinical study using this same supplement and dose for 2 weeks found no benefit when compared with placebo (17463). It is possible that a 2-week duration of treatment is too short to be beneficial. Finally, a meta-analysis of these studies and one other more recent clinical study shows that taking magnesium does not reduce the frequency or improve the resolution of pregnancy-related leg cramps when compared with placebo (105916). This analysis may not have been adequately powered to detect a difference between treatment groups.
• Pre-procedural sedation. It is unclear if intravenous magnesium is beneficial when administered in addition to other medications used for sedation during surgery. Details: A moderate-sized study of adults aged 65-79 years old undergoing endoscopic retrograde cholangiopancreatography (ERCP) shows that administering a single intravenous bolus of magnesium sulfate 40 mg/kg prior to the procedure reduces intraoperative propofol requirements by about 21% and reduces some peri-procedural adverse events including the incidence of respiratory depression and involuntary movement when compared with control. However, there were no differences in recovery time, hemodynamic parameters, or the incidence of hypotension, bradycardia, perioperative nausea or vomiting, lethargy, or arrythmias (111694). Another moderate-sized study in older adults undergoing total knee arthroplasty shows that administering intravenous magnesium sulfate 40 mg/kg prior to anesthesia induction then 15 mg/kg during surgery does not reduce the need for medications used for anesthesia induction, intraoperative maintenance propofol requirements, or recovery time when compared with control. However, magnesium sulfate does seem to reduce the amount of remifentanil required for intraoperative anesthesia maintenance and increase norepinephrine requirements when compared with control (113677).
• Preterm labor. The use of magnesium sulfate to inhibit uterine contractions in preterm labor (tocolysis) is controversial. However, its use for the purpose of fetal neuroprotection for up to 48 hours is supported by the American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine. Details: Magnesium is given intravenously (IV) during preterm labor in an effort to improve fetal neurological outcomes, such as to reduce the risk of cerebral palsy and motor dysfunction in the infant (60915,60927,60931,61001,97485,103734,103754,114681). The typical dosage of magnesium sulfate is 4 grams infused IV over 10-30 minutes, followed by a maintenance infusion of 1-4 grams/hour for 48 hours or until birth. Use beyond 5-7 days has been associated with hypocalcemia and bone abnormalities in the fetus (15,12590,12594). Some meta-analyses of clinical research suggest that magnesium sulfate is more effective at delaying delivery by 48 hours when compared with oxytocin receptor blockers, nitrates, beta-mimetics, and/or placebo (20263,61021). However, an additional meta-analysis of several clinical studies shows that magnesium sulfate 4 or 6 grams IV is not more effective at delaying preterm labor by 48 hours when compared with nifedipine (115639). The reason for these discrepant findings are unclear, but may be related to the heterogenous methods between clinical trials, including dose and duration.
• Pseudoxanthoma elasticum (PXE). It is unclear if oral magnesium is beneficial for PXE. Details: Preliminary clinical research in patients with PXE shows that taking magnesium oxide 800 mg (500 mg of elemental magnesium) twice daily for one year tends to reduce calcification of elastic skin fibers when compared with placebo, but the effect is not statistically significant (101393). This study was limited by small size and insufficient power to detect smaller effects.
• Restless legs syndrome (RLS). It is unclear if oral magnesium is beneficial for RLS. Details: Some observational research has found that hypomagnesemia is associated with RLS; however, not all research agrees (8096,9472). Preliminary clinical research in adults with RLS who are beginning treatment with pramipexole shows that also taking magnesium oxide 250 mg orally daily for 2 months moderately improves RLS scores and sleep quality scores when compared with pramipexole and placebo (110052). Other low-quality clinical research in adults with RLS or periodic limb movement during sleep shows that taking magnesium 12.4 mmol orally in the evening for 4-6 weeks decreases movement and increases sleep when compared with baseline (9466). The validity of this finding is limited by the lack of a comparator group.
• Sarcopenia. It is unclear if oral magnesium is beneficial for the prevention or treatment of sarcopenia. Details: Population research in older adults has found that lower dietary intake of magnesium is associated with sarcopenia. However, the effect of magnesium supplementation on sarcopenia prevention or treatment has not been evaluated (110055). Magnesium has been evaluated in combination with other ingredients for treatment of sarcopenia. A small clinical study in elderly individuals with sarcopenia undergoing a diet and exercise program shows that taking a combination supplement containing magnesium 300 mg, carnosine, hydroxymethylbutyrate, lactoferrin, and sodium butyrate daily for 4 months increases muscle mass, as measured by the skeletal muscle index, and improves measures of muscle function, including handgrip muscle strength, chair test, and walking speed, when compared with placebo (114682). It is unclear if these effects are due to magnesium, other ingredients, or the combination.
• Sepsis. It is unclear if intravenous magnesium is beneficial for sepsis. Details: A very large observational study in patients with sepsis and hypomagnesaemia or normomagnesemia in the intensive care unit (ICU) suggests that administering intravenous magnesium sulfate 2 or 4 grams within 24 hours of admission reduces 28-day all-cause mortality from 25% in patients who did not use magnesium sulfate to 20% in those who were administered magnesium sulfate, regardless of baseline serum magnesium level and other baseline characteristics. Administration of intravenous magnesium sulfate in this population may also reduce ICU mortality by 4%, in-hospital mortality by 3%, and the use of renal replacement therapy by 3% but also seems to increase the length of ICU and hospital stay when compared with patients who did not use magnesium sulfate (113676). The validity of these results is limited by the observational nature of the study.
• Sleep deprivation. Oral magnesium has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A very small clinical study in sleep-deprived recreational athletes shows that taking a combination of magnesium 1350 mg, zinc 90 mg, and vitamin B6 31.5 mg for 3 nights at bedtime does not change sleep quality, subjective sleepiness, mood, or fatigue the next day when compared with placebo (113655).
• Stroke. Increased dietary magnesium may decrease stroke risk, and using a magnesium-containing salt substitute may improve neurological performance post-stroke. However, intravenous magnesium has not demonstrated benefit. Details: Most population research has found that increased dietary intake of magnesium is associated with decreased stroke risk and decreased mortality from stroke (9001,9002,90013,90030,90036,92107,103736). In patients who have had a stroke, a preliminary clinical study shows that using a salt substitute providing the Dietary Reference Intake (DRI) of magnesium and potassium for 6 months improves neurological performance when compared with using regular salt (97491). However, intravenous (IV) magnesium does not seem to be beneficial in patients who have had a stroke. Large prospective clinical trials show that IV magnesium given within 12 hours of acute stroke does not reduce mortality or disability in most patients when compared with placebo. However, one subgroup analysis suggested that IV magnesium might benefit patients with lacunar (non-cortical) stroke (13361,90021). IV magnesium also doesn't seem to reduce cardiovascular complications after acute stroke. A secondary analysis of a clinical trial in patients after ischemic and hemorrhagic stroke shows that giving IV magnesium does not reduce serious cardiac adverse events when compared with placebo (104393). Another secondary analysis of this trial shows that giving IV magnesium prior to arrival at the hospital and within 2 hours of a hemorrhagic stroke does not reduce hematoma volume on hospital arrival, hematoma expansion during hospital admission, or functional outcomes at 3 months (108733).
• Subarachnoid hemorrhage. Intravenous magnesium sulfate may reduce the risk of adverse outcomes in people with subarachnoid hemorrhage, but evidence is conflicting. Details: There is mixed evidence regarding the effect of magnesium sulfate in managing aneurysmal subarachnoid hemorrhage. One meta-analysis of clinical research shows that intravenous magnesium sulfate 64-144 mmol/day for 10-18 days reduces the risk of poor outcomes following aneurysmal subarachnoid hemorrhage, including death, vegetative state, or dependency, by 46% when compared with control (60932). Also, meta-analyses of clinical research show that intravenous magnesium reduces the risk of delayed cerebral ischemia by 27% when compared with placebo (60944,89398). However, these results were not confirmed in other meta-analyses (60973,90034).
• Thrombocytopenia. It is unclear if intravenous magnesium sulfate is beneficial in patients with thrombotic thrombocytopenic purpura (TTP). Details: Addition of intravenous magnesium sulfate as a 6-gram loading dose followed by 6 grams infused over 24 hours for 3 days, to standard treatment for TTP does not reduce the time to normalization of the platelet count, the incidence of TTP-related organ dysfunction, or the recurrence rate, when compared with standard treatment alone (112777). This study may have been underpowered to detect a difference.
• Urinary incontinence. Although there has been interest in using oral magnesium for urinary incontinence, there is insufficient reliable information about the clinical effects of magnesium for this purpose. More evidence is needed to rate magnesium for these uses.

(Read more about MAGNESIUM)

EFFECTIVE

• Pantothenic acid deficiency. Taking pantothenic acid 5-10 mg daily is effective for treating and preventing pantothenic acid deficiency (15).

POSSIBLY INEFFECTIVE

• Radiation dermatitis. Topical dexpanthenol does not seem to be beneficial for preventing or treating radiation dermatitis. Details: Applying dexpanthenol, an analog of pantothenic acid, twice daily to areas of irradiated skin does not seem to reduce erythema, desquamation, itching, or pain following radiation treatment (7192). Also, applying dexpanthenol 0.5% cream (Bepanthen, Hoffmann LaRoche ) daily during radiation therapy and for 2 weeks after completing radiation therapy is less effective than methylprednisolone aceponate 0.1% cream (Advantan) at reducing radiation-induced skin irritation (67779).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Acne. Oral or topical pantothenic acid has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: In adults with mild to moderate acne, clinical research shows that taking a specific supplement (Pantothen, Avilan Marketing LLC) providing pantothenic acid 1.1 grams twice daily in addition to other B vitamins for 12 weeks modestly reduces total and non-inflammatory lesion counts when compared with placebo (105188). Also, in adolescents or young adults with mild to moderate acne, preliminary clinical research shows that topical application with a gel containing D-panthenol 4%, hydrogen peroxide 4%, and salicylic acid 0.5% once daily for 60 days modestly reduces acne lesions when compared with baseline (105189). The validity of this finding is limited by the lack of a comparator group.
• Alcoholism. Although there is interest in using oral pantothenic acid for improving recovery from alcoholism, there is insufficient reliable information about the clinical effects of pantothenic acid for this condition.
• Allergic rhinitis (hay fever). Although there is interest in using oral pantothenic acid for allergic rhinitis, there is insufficient reliable information about the clinical effects of pantothenic acid for this condition.
• Alopecia areata. Pantothenic acid has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in healthy adults with diffuse hair loss shows that intramuscular administration of dexpanthenol 250 mg and biotin 5 mg once weekly for 6 weeks reduces hair fall count at weeks 1 and 8, but only increases hair density at week 1, when compared to baseline (111366). The validity of these findings is limited by the study's small size, short duration, and lack of comparator group.
• Anxiety. Although there is interest in using oral pantothenic acid for anxiety, there is insufficient reliable information about the clinical effects of pantothenic acid for this purpose.
• Asthma. Although there is interest in using oral pantothenic acid for asthma, there is insufficient reliable information about the clinical effects of pantothenic acid for this condition.
• Athletic performance. Although there is interest in using oral pantothenic acid to improve athletic performance, there is insufficient reliable information about the clinical effects of pantothenic acid for this purpose.
• Attention deficit-hyperactivity disorder (ADHD). Oral pantothenic acid has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Some small outdated clinical studies in children diagnosed with hyperkinesis suggest that taking calcium pantothenate 1.2 grams, alone or in combination with niacinamide, ascorbic acid, and pyridoxine, does not improve symptoms of hyperactivity when compared with placebo (3351,9957). It is unclear what effects pantothenic may have, if any, in children with a modern diagnosis of ADHD.
• Atopic dermatitis (eczema). It is unclear if topical pantothenic acid is beneficial in infants or children with atopic dermatitis. Details: One preliminary clinical trial in infants and children with stable mild atopic dermatitis shows that topical application of an emollient containing panthenol (Bepanthen, SensiDaily, Bayer Consumer Care AG) for 3 months is as effective as a reference emollient for reducing symptoms and preventing a flare. However, the efficacy of the reference emollient (Stelatopia Emollient Cream, Mustela; Laboratoires Expanscience) is unclear based on available preliminary clinical research (105190).
• Autism spectrum disorder. Although there is interest in using oral pantothenic acid for autism spectrum disorder, there is insufficient reliable information about the clinical effects of pantothenic acid for this condition.
• Carpal tunnel syndrome. Although there is interest in using oral pantothenic acid for carpal tunnel syndrome, there is insufficient reliable information about the clinical effects of pantothenic acid for this condition.
• Cheilitis. Topical pantothenic acid has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small, open-label study in adults with mild-to-moderate cheilitis shows that applying a specific lip care product containing pantothenic acid and bisabolol (Eucerin Aquaphor SOS lip care) at least twice daily for 8 weeks reduces cheilitis severity scores by 5 points on a 12 point scale assessing erythema, scale, fissure, and inflammation when compared to baseline (114549). The validity of this finding is limited by the small study size and lack of a comparator group. Additionally, it is unclear if this effect is due to pantothenic acid, bisabolol, or the combination.
• Chronic fatigue syndrome (CFS). Although there is interest in using oral pantothenic acid for CFS, there is insufficient reliable information about the clinical effects of pantothenic acid for this condition.
• Conjunctivitis. Although there is interest in using oral or ocular pantothenic acid for conjunctivitis, there is insufficient reliable information about the clinical effects of pantothenic acid for this condition.
• Constipation. It is unclear if oral or intramuscular dexpanthenol is beneficial for constipation. Details: Preliminary clinical research shows that administering dexpanthenol (Bepanthene), an analog of pantothenic acid, 400 mg orally or 500 mg intramuscularly daily for 5 days decreases the time to a bowel movement in patients with chronic or occasional constipation when compared with an oral placebo (67822).
• Dandruff. Although there is interest in using oral or topical pantothenic acid for dandruff, is insufficient reliable information about the clinical effects of pantothenic acid for this condition.
• Depression. Although there is interest in using oral pantothenic acid for depression, there is insufficient reliable information about the clinical effects of pantothenic acid for this condition.
• Diaper rash. Although there is interest in using topical pantothenic acid for diaper rash, there is insufficient reliable information about the clinical effects of pantothenic acid for this condition.
• Dry eye. Although there is interest in using ocular pantothenic acid for dry eye, there is insufficient reliable information about the clinical effects of pantothenic acid for this condition.
• Dry skin. It is unclear if topical dexpanthenol is beneficial for patients with dry skin. Details: A small, open-label study in healthy adults with dry skin shows that cleansing the skin with a dexpanthenol-containing liquid cleanser (DCLC, Bepanthen SensiControl Daily Gentle Body Wash) daily for 4 weeks increases stratum corneum hydration by 17% without affecting skin barrier function, pH, or microbiome when compared to baseline (111262). The validity of these findings is limited by the lack of blinding and a comparator group.
• Epilepsy. Although there is interest in using oral pantothenic acid for epilepsy, there is insufficient reliable information about the clinical effects of pantothenic acid for this condition.
• Eye trauma. It is unclear if ocular dexpanthenol is beneficial for eye trauma. Details: Some preliminary clinical research shows that using eyedrops containing dexpanthenol 5%, a derivative of pantothenic acid, two drops four times daily for 28 days following surgery for retinal detachment reduces eye pain and discomfort when compared with placebo drops (67783). However, using a specific dexpanthenol 5% ointment (Bepanthen) does not seem to improve corneal epithelial wound healing following phototherapeutic keratectomy when compared with placebo (67801).
• Heart failure. Although there is interest in using oral pantothenic acid for heart failure, there is insufficient reliable information about the clinical effects of pantothenic acid for this condition.
• Herpes zoster (shingles). Although there is interest in using oral or topical pantothenic acid for shingles, there is insufficient reliable information about the clinical effects of pantothenic acid for this condition.
• Insomnia. Although there is interest in using oral pantothenic acid for insomnia, there is insufficient reliable information about the clinical effects of pantothenic acid for this condition.
• Laser skin resurfacing. It is unclear if topical dexpanthenol or pantothenic acid can reduce adverse effects after laser skin resurfacing procedures. Details: A preliminary clinical study shows that use of a dexpanthenol-containing ointment (Bepanthen Wound Healing Ointment, Bayer) once daily modestly reduces the diameter of lesions up to 3 days after fractional carbon dioxide laser resurfacing when compared with petroleum jelly (105743). Also, applying a specific cream (Cicaplast Baume B5 cream, L'Oreal) containing panthenol 5%, madecassoside, copper, zinc, and manganese to one side of the face for 28 days reduces decrustation time by approximately one day when compared with a control emollient. Redness and swelling were lower at 3 days, but there was no difference in pain and burning (105742). It is unclear if these effects are due to pantothenic acid, other ingredients, or the combination.
• Multiple sclerosis (MS). Although there is interest in using oral pantothenic acid for MS, there is insufficient reliable information about the clinical effects of pantothenic acid for this condition.
• Muscular dystrophy. Although there is interest in using oral pantothenic acid for muscular dystrophy, there is insufficient reliable information about the clinical effects of pantothenic acid for this condition.
• Nipple fissures. Although there is interest in using topical pantothenic acid for nipple fissures, there is insufficient reliable information about the clinical effects of pantothenic acid for this condition.
• Obesity. Although there is interest in using oral pantothenic acid for obesity, there is insufficient reliable information about the clinical effects of pantothenic acid for this condition.
• Pain (chronic). It is unclear if oral or topical pantothenic acid is beneficial for the management of various forms of chronic pain. Details: Although there is interest in using oral or topical pantothenic acid for various forms of chronic pain, including neuropathy and arthritis, there is limited information available about the clinical effects of pantothenic acid for this purpose. One review of preliminary clinical research found that calcium pantothenate does not reduce symptoms of arthritis in patients with rheumatoid arthritis or osteoarthritis (10433).
• Parkinson disease. Although there is interest in using oral pantothenic acid for Parkinson disease, there is insufficient reliable information about the clinical effects of pantothenic acid for this condition.
• Poison oak and poison ivy dermatitis. Although there is interest in using topical pantothenic acid for poison ivy dermatitis, there is insufficient reliable information about the clinical effects of pantothenic acid for this condition.
• Postoperative pain. It is unclear if oral pantothenic acid is beneficial for postoperative pain. Details: In post-tonsillectomy patients aged 5-12 years, preliminary clinical research shows that taking pastilles containing dexpanthenol (Bepanthene, Bayer) 100 mg three times daily reduces pain when compared with placebo. Postoperative pain was modestly reduced at 1, 3, 7, and 14 days after surgery (105191).
• Postoperative sore throat. It is unclear if pantothenic acid lozenges are beneficial for postoperative sore throat. Details: Preliminary clinical research shows that taking two lozenges containing dexpanthenol, an analog of pantothenic acid, 200 mg 30 minutes prior to general anesthesia reduces the incidence and severity of postoperative sore throat when compared with a benzydamine hydrochloride or placebo spray (67792).
• Pregnancy-related leg cramps. Although there is interest in using oral pantothenic acid for pregnancy-related leg cramps, there is insufficient reliable information about the clinical effects of pantothenic acid for this condition.
• Premenstrual syndrome (PMS). Although there is interest in using oral pantothenic acid for PMS, there is insufficient reliable information about the clinical effects of pantothenic acid for this condition.
• Respiratory tract infections. Although there is interest in using oral pantothenic acid for respiratory tract infections, there is insufficient reliable information about the clinical effects of pantothenic acid for this condition.
• Rhinosinusitis. It is unclear if nasal dexpanthenol is beneficial for rhinosinusitis. Details: Preliminary clinical research shows that using a nasal spray (MarPlus) containing dexpanthenol, an analog of pantothenic acid, on the first, second, fourth, and sixth week after endoscopic sinus surgery reduces nasal discharge, but not other symptoms associated with chronic rhinosinusitis, when compared with saline nasal spray (67808).
• Skin irritation. It is unclear if topical dexpanthenol is beneficial for preventing or treating skin irritation due to sodium lauryl sulfate. Details: Preliminary clinical research shows that applying dexpanthenol (Bepanthol Handbalsam), an analog of pantothenic acid, twice daily for 26 days does not prevent sodium lauryl sulfate-induced skin irritation (67785). However, dexpanthenol may be effective for treating skin irritation caused by sodium lauryl sulfate. Use of an ointment containing dexpanthenol 1% to 5% twice daily for up to 30 days following skin exposure to sodium lauryl sulfate seems to reduce skin water loss, skin roughness, and skin inflammation when compared to control (67802,67806).
• Ulcerative colitis. Although there is interest in using oral or rectal pantothenic acid for ulcerative colitis, there is insufficient reliable information about the clinical effects of pantothenic acid for this condition.
• Vertigo. Although there is interest in using oral pantothenic acid for vertigo, there is insufficient reliable information about the clinical effects of pantothenic acid for this condition.
• Wound healing. Preliminary clinical research suggests that oral dexpanthenol might be beneficial for wound healing. Details: In post-tonsillectomy patients aged 5-12 years, preliminary clinical research shows that taking pastilles containing dexpanthenol (Bepanthene, Bayer) 100 mg three times daily improves wound healing when compared with placebo. Depending on the type of surgery, wound healing occurred in 2.3-2.9 times as many patients within 7 days of surgery, and in 13% to 35% more patients within 14 days, when compared with placebo (105191). More evidence is needed to rate pantothenic acid for these uses.

(Read more about PANTOTHENIC ACID)

POSSIBLY INEFFECTIVE

• Hyperlipidemia. Preliminary clinical studies show that oral reishi mushroom does not improve lipid levels in patients with hyperlipidemia or type 2 diabetes. Details: Preliminary clinical research shows that taking reishi mushroom extract 1440 mg daily for 12 weeks does not significantly improve the lipid profile in patients with hyperlipidemia (70776). Also, a meta-analysis shows that taking reishi mushroom extract 1400-4000 mg daily for 12-16 weeks does not reduce total cholesterol or low-density lipoprotein (LDL) cholesterol in patients with type 2 diabetes (91435).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Aging. Although there has been interest in using oral reishi mushroom for aging, there is insufficient reliable information about the clinical effects of reishi mushroom for this purpose.
• Altitude sickness. Although there has been interest in using oral reishi mushroom for altitude sickness, there is insufficient reliable information about the clinical effects of reishi mushroom for this purpose.
• Alzheimer disease. A small clinical study suggests that oral reishi mushroom does not improve Alzheimer disease symptoms. Details: Preliminary clinical research in patients with Alzheimer disease shows that taking reishi mushroom powder 1000 mg three times daily for 6 weeks does not improve memory, language skills, or quality of life when compared with placebo (97942).
• Asthma. Although there has been interest in using oral reishi mushroom for asthma, there is insufficient reliable information about the clinical effects of reishi mushroom for this purpose.
• Benign prostatic hyperplasia (BPH). Preliminary clinical research suggests that oral reishi mushroom extract can help reduce some lower urinary tract symptoms in patients with BPH. Details: Clinical research in patients with mild to moderate lower urinary tract symptoms (LUTS) associated with BPH, urinary incontinence, overactive bladder, or other conditions, shows that taking reishi mushroom extract 6 mg orally once daily for up to 12 weeks moderately improves total symptom severity measured on the International Prostate Symptom Score (IPSS) scale, when compared with placebo (91436,91437). A higher dose of 60 mg daily is not more effective than the 6 mg dose, and a lower dose of 0.6 mg daily is not more effective than placebo (91437). Reishi mushroom extract does not improve peak urine flow rate, residual urine volume, prostate volume, or quality of life when compared with placebo (91436,91437). The relevance of these results is unclear since not all of the patients with LUTS had BPH.
• Bronchitis. Although there has been interest in using oral reishi mushroom for bronchitis, there is insufficient reliable information about the clinical effects of reishi mushroom for this purpose.
• Cancer. It is unclear if oral reishi mushroom is beneficial when used in conjunction with chemotherapy. Details: A meta-analysis of 9 clinical trials using various reishi mushroom products in combination with chemotherapy found that complete and partial responses increased by 30% with combination therapy when compared with chemotherapy alone. However, there was no difference in overall survival (102915). The reliability and applicability of these results are unclear since the trials looked at several different types of cancer, used varying doses and durations of therapy, and were all conducted in China or other Asian countries.
• Cancer-related fatigue. It is unclear if oral reishi mushroom is beneficial in patients with breast cancer and fatigue. Details: Results from a small clinical study in breast cancer patients show that taking reishi mushroom powder 1000 mg orally three times daily for 4 weeks can improve cancer-related fatigue when compared with placebo (91438). However, it is not clear if the improvement is clinically meaningful.
• Cardiovascular disease (CVD). It is unclear if oral reishi mushroom is beneficial for reducing CVD risk factors. Details: A meta-analysis of 5 low-quality studies in adults with diabetes shows that taking reishi mushroom 1400-3000 mg daily for 12-16 weeks does not reduce CVD risk factors, including total and low-density lipoprotein (LDL) cholesterol, triglycerides, blood pressure, and body mass index, when compared with placebo (91435).
• Chronic fatigue syndrome (CFS). Although there has been interest in using oral reishi mushroom for CFS, there is insufficient reliable information about the clinical effects of reishi mushroom for this purpose.
• Chronic kidney disease (CKD). Although there has been interest in using oral reishi mushroom for CKD, there is insufficient reliable information about the clinical effects of reishi mushroom for this purpose.
• Colorectal adenoma. Limited clinical research suggests that oral reishi mushroom extract may be beneficial for reducing colorectal adenoma size. Details: Preliminary clinical research in patients with colorectal adenomas shows that taking reishi mushroom extract 1500 mg orally in two divided doses daily for 12 months reduces the number and size of adenomas when compared with no treatment (70774).
• Coronary heart disease (CHD). It is unclear if oral reishi mushroom is beneficial for CHD. Details: Preliminary clinical research shows that taking a specific reishi mushroom extract (Ganopoly, Encore International Co.) 1800 mg orally three times daily for 12 weeks reduces symptoms of CHD, such as chest pain, palpitations, and shortness of breath, in a greater percentage of patients when compared with placebo (70800).
• Diabetes. Evidence on the use of oral reishi mushroom in patients with type 2 diabetes is conflicting. Details: A meta-analysis of clinical research in patients with type 2 diabetes shows that taking reishi mushroom extract 1400-4000 mg daily for 12-16 weeks does not reduce glycated hemoglobin (HbA1c) or plasma lipids (91435). However, one preliminary clinical study in patients with type 2 diabetes shows that taking a specific reishi mushroom extract (Ganopoly, Encore International Co.) 1800 mg three times daily for 12 weeks reduces HbA1c, but not fasting blood glucose, when compared with placebo (70801).
• Fibromyalgia. It is unclear if oral reishi mushroom is beneficial for fibromyalgia. Details: A small clinical trial in patients with fibromyalgia shows that taking reishi mushroom (MundoReishi Salud S.L.) powder 3 grams twice daily for 6 weeks does not improve mood, quality of life, anthropometric measures, blood pressure, or glycemic or lipid parameters when compared with placebo (108309,108310). However, the study may have been underpowered to detect any differences between groups.
• Genital herpes. Oral reishi mushroom has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in adults with recurrent genital herpes shows that taking 4.4 grams of a mixture of hot water extracts of reishi mushroom, terminalia, Job's tears, Wisteria floribunda, Trapa natans, and Elfvingia applanata orally once daily for 2 days, then 2.2 grams daily thereafter until outbreak resolution, decreases the time to outbreak resolution by 6 days when compared with previous outbreaks (91434).
• Gulf war syndrome. It is unclear if oral reishi mushroom is beneficial for Gulf war syndrome. Details: A very small exploratory clinical trial in adults with Gulf war syndrome shows that taking reishi mushroom extract (JHS Natural Products, Mushroom Science) 1600 mg in two divided doses daily for 30 days does not improve symptoms when compared with placebo. Also, symptoms modestly worsened after an additional 30 days of treatment at a dose of 3200 mg daily (108311).
• Hepatitis B. One small clinical study suggests that a specific reishi mushroom extract may reduce hepatitis B activity and improve liver function. Details: Preliminary clinical research shows that taking a specific reishi mushroom extract (Ganopoly, Encore International Co.) 1800 mg orally three times daily for 12 weeks reduces levels of hepatitis B viral DNA and hepatitis B surface antigen, which are markers of hepatitis B activity, and normalizes aminotransferase levels in a greater percentage of patients when compared with placebo (70799).
• Herpes labialis (cold sores). Oral reishi mushroom has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in adults with recurrent herpes labialis shows that taking 4.4 grams of a mixture of hot water extracts of reishi mushroom, terminalia, Job's tears, Wisteria floribunda, Trapa natans, and Elfvingia applanata orally once daily for 2 days, then 2.2 grams daily thereafter until outbreak resolution, decreases the time to outbreak resolution by almost 4 days when compared with previous outbreaks (91434).
• Herpes zoster (shingles). Although there has been interest in using oral reishi mushroom for herpes zoster, there is insufficient reliable information about the clinical effects of reishi mushroom for this purpose.
• Human papillomavirus (HPV). Oral reishi mushroom has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in patients with oral HPV shows that taking a combination of reishi and coriolus mushroom powders, 400 mg orally daily for 2 months, clears HPV in 88% of patients when compared with baseline (91433). The validity of this finding is limited by the lack of a comparator group.
• Hypertension. Limited research suggests that oral reishi mushroom may be beneficial in some types of hypertension. Details: Preliminary clinical research shows that taking reishi mushroom extract 1440 mg daily for 12 weeks does not lower blood pressure in patients with hypertension (70776). However, in other clinical research, taking reishi mushroom extract 330-1440 mg daily for 1-6 months reduces blood pressure in patients with stage II or essential hypertension, but not in those with mild hypertension or diabetes (70786,70802,91435).
• Influenza. Although there has been interest in using reishi mushroom for influenza, there is insufficient reliable information about the clinical effects of reishi mushroom for this purpose.
• Insomnia. Although there has been interest in using reishi mushroom for insomnia, there is insufficient reliable information about the clinical effects of reishi mushroom for this purpose.
• Lung cancer. Small clinical studies suggest that oral reishi mushroom does not reduce the size of lung tumors. Details: A meta-analysis of preliminary clinical research shows that taking reishi mushroom does not reduce the size of lung tumors. However, it may stimulate immune function and improve quality of life in lung cancer patients when compared with control (70779).
• Peptic ulcers. Although there has been interest in using oral reishi mushroom for peptic ulcers, there is insufficient reliable information about the clinical effects of reishi mushroom for this purpose.
• Rheumatoid arthritis (RA). Oral reishi mushroom has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical trial in patients with active RA who are taking disease-modifying antirheumatic drugs shows that taking reishi mushroom extract 4 grams in combination with San Miao San (containing 2.4 grams each of atractylodes, phellodendron, and Achyranthes bidentata) daily for 24 weeks does not increase the percentage of patients achieving a 20% response based on the American College of Rheumatology (ACR) criteria or modify blood markers of disease and inflammation when compared with placebo (70767).
• Stress. Although there has been interest in using oral reishi mushroom for stress, there is insufficient reliable information about the clinical effects of reishi mushroom for this purpose. More evidence is needed to rate reishi mushroom for these uses.

(Read more about REISHI MUSHROOM)

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Altitude sickness. It is unclear if oral rhodiola is beneficial for altitude sickness. Details: Preliminary clinical research shows that taking rhodiola 447 mg four times daily for 7 days does not improve blood oxygenation or markers of oxidative stress when compared with placebo in subjects exposed to simulated high-altitude conditions (25402).
• Anthracycline cardiotoxicity. It is unclear if oral rhodiola is beneficial for epirubicin-induced cardiotoxicity. Details: Preliminary clinical research in breast cancer patients shows that taking salidroside, a constituent of rhodiola, 600 mg daily, beginning one week prior to chemotherapy and continuing throughout chemotherapy administration, reduces epirubicin-induced early left ventricular regional systolic dysfunction when compared with placebo (90434).
• Anxiety. It is unclear if oral rhodiola is beneficial for anxiety. Details: Preliminary clinical research in college students with anxiety shows that taking a specific dried rhodiola extract (Vitango, Schwabe Pharma) 200 mg twice daily for 14 days modestly reduces reported levels of anxiety, anger, confusion, negative mood, and stress when compared with a control group. However, rhodiola extract does not seem to improve cognition (96462).
• Arrhythmia. Although there has been interest in using oral rhodiola for arrhythmia, there is insufficient reliable information about the clinical effects of rhodiola for this condition.
• Athletic performance. The evidence related to the use of rhodiola for athletic performance is mixed, although specific standardized extracts might be beneficial for certain performance endpoints. Details: The available evidence for rhodiola in athletic performance includes small clinical trials in recreationally active or trained athletes. Trials using rhodiola extracts standardized to 3% rosavins and 1% salidroside (eg. Finzelberg, GmbH) show that taking 3 mg/kg, 200 mg, or 500 mg prior to exercise testing, either as a single dose or with a 3-day lead-in dose, modestly improves performance endpoints on a cycle ergometer. Improved endpoints included time to exhaustion, peak oxygen use, time to completion, perceived exhaustion, anaerobic capacity, and power (13109,90432,100168). However, in trials in which rhodiola was not taken the morning of testing, or when performance endpoints included forearm endurance or marathon time and recovery, rhodiola 170 mg to 1500 mg daily did not affect perceived exertion, time to exhaustion, or peak oxygen use (15574,19284,90433). A small crossover trial shows that taking 500 mg of rhodiola extract, standardized to 3% rosavins and 1% salidroside, three times daily for 3 days followed by 500 mg 30-minutes before exercise testing increases bench press velocity but decreases bench press repetition volume when compared with placebo (110543). Furthermore, limited evidence suggests that rhodiola extract does not affect muscle strength, speed of limb movement, reaction times, or attention span (13109) but might reduce plasma creatine kinase levels (19284). Also, while some evidence suggests that rhodiola extract can reduce blood lactate levels (19284), other research shows that it increases blood lactate levels after resistance training to a greater degree than placebo (110543). In general, it appears that acute doses of rhodiola may improve specific physical performance parameters, but neither acute nor chronic doses appear to notably improve muscle function. Some research has also assessed rhodiola when used in combination with other ingredients. A small clinical study in trained male cyclists shows that taking a specific combination product (Optygen, First Endurance) containing rhodiola 600 mg (standardized to 3% rosavin and 2.5% salidroside) plus cordyceps 2000 mg (standardized to 7% cordycepic acid), daily for 6 days followed by a half-dose daily for 7 days does not improve time to exhaustion or muscle tissue oxygen saturation when compared with placebo (15573). Additionally, a small crossover study in healthy, recreationally active adult males shows that taking a 30:70 blend of rhodiola and maral root extracts at a dose of 350 mg or 175 mg, ninety minutes prior to isokinetic leg strength exercises, does not influence fatigability, performance variables, or affective responses when compared with placebo (105855).
• Bladder cancer. Although there has been interest in using oral rhodiola for bladder cancer, there is insufficient reliable information about the clinical effects of rhodiola for this condition.
• Chronic fatigue syndrome (CFS). Although there has been interest in using oral rhodiola for CFS, there is insufficient reliable information about the clinical effects of rhodiola for this condition.
• Coronavirus disease 2019 (COVID-19). Oral rhodiola extract has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in adults a with confirmed history of COVID-19 infection and at least 3 of 9 long COVID-19 symptoms for at least 30 days, but no longer than 3 months, after discharge shows that taking a specific combination product (ADAPT-232/Chisan, Swedish Herbal Institute), containing rhodiola extract 90 mg, schisandra extract 300 mg, and eleuthero extract 78 mg, twice daily for 14 days increases walking duration by around 13 minutes but does not reduce the duration of cough, fatigue, headache, pain, or other respiratory problems when compared with placebo (109635). It is unclear if these findings are due to rhodiola, other ingredients, or the combination.
• Depression. It is unclear if oral rhodiola is beneficial for depression. Details: Clinical practice guidelines from the World Federation of Societies of Biological Psychiatry (WFSBP) and the Canadian Network for Mood and Anxiety Treatments (CANMAT) state that rhodiola is not currently recommended for monotherapy or adjunctive use in major depressive disorder based on mixed evidence (110318). Clinical research shows that taking a specific rhodiola extract (SHR-5, Swedish Herbal Institute) 340 mg once or twice daily reduces symptoms of mild-to-moderate depression after 6 weeks of treatment when compared with placebo. Rhodiola decreased overall depressive symptoms, emotional instability, insomnia, and somatization; however, it did not improve feelings of self-esteem (17616). Another small clinical study in patients with major depressive disorder of moderate severity shows that adding a higher dose of rhodiola 600 mg to sertraline daily for 12 weeks improves depressive symptoms when compared with either sertraline alone or sertraline with a lower dose of rhodiola (300 mg) (102283).
• Diabetes. Although there has been interest in using oral rhodiola for diabetes, there is insufficient reliable information about the clinical effects of rhodiola for this condition.
• Fatigue. Preliminary clinical research suggests that oral rhodiola extract decreases fatigue in stressful situations. Details: Most preliminary clinical trials have evaluated a specific rhodiola root extract (SHR-5, Swedish Herbal Institute) in various doses and populations. Taking 50 mg of this product twice daily reduces mental fatigue and improves subjective well-being in students during an examination period (1927). Taking 144 mg twice daily for 7 days reduces fatigue, but not stress, in university students (19287). In night shift workers, 170 mg daily for 2 weeks reduces feelings of fatigue and improves mental performance (6877). In military cadets, a single dose of 370-555 mg after 24 hours without sleep improves tests of mental processing and short-term memory (16411). Finally, taking 576 mg daily for 28 days decreases symptoms of fatigue and increases attention, but does not improve quality of life or symptoms of depression, in patients with stress-related fatigue (19286). Other clinical research shows that taking a different rhodiola root extract (Rhodaxon, Teknofarm), 660 mg daily for 20 days, reduces mental fatigue by 30% in first-year university students (19288). Clinical research using another specific dried rhodiola extract (Vitango, Schwabe Pharma) also shows that taking 200 mg twice daily for 12 weeks modestly reduces perceived levels of stress, burnout, and fatigue when compared to baseline in adults experiencing symptoms of burnout. The validity of these findings is limited by the lack of a control group (96459). Rhodiola extract has also been studied in combination schisandra berry extract and Siberian ginseng root extract (ADAPT-232, Swedish Herbal Institute). However, evidence is mixed, with one study showing that 270 mg daily improves attention, accuracy, and speed in tired individuals performing stressful cognitive tasks (19289), and another study showing that 280 mg daily for 7 days does not reduce mental fatigue or stress in university students (19287).
• Generalized anxiety disorder (GAD). It is unclear if oral rhodiola is beneficial for GAD. Details: A small clinical study shows that taking a specific rhodiola extract (Rhodax, Bodyonics Ltd.) 170 mg twice daily for 10 weeks decreases anxiety and depression and improves symptom scores when compared to baseline in patients with GAD (16410). The validity of these findings is limited by the lack of a comparator group.
• Hearing loss. Although there has been interest in using oral rhodiola for hearing loss, there is insufficient reliable information about the clinical effects of rhodiola for this purpose.
• Hyperlipidemia. Although there has been interest in using oral rhodiola for hyperlipidemia, there is insufficient reliable information about the clinical effects of rhodiola for this condition.
• Menopausal symptoms. Oral rhodiola has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in patients experiencing menopausal symptoms shows that taking a combination product (Menopause Relief EP, EuroPharma USA) containing rhodiola extract 400 mg and black cohosh extract 13 mg daily for 12 weeks improves psychological symptoms of menopause when compared with placebo or black cohosh alone (103269). It is unclear if these findings are due to rhodiola, black cohosh, or the combination.
• Premature ejaculation. Oral rhodiola has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in adults with lifelong premature ejaculation shows that taking a specific combination product (EndEP) containing rhodiola 200 mg, folic acid 200 mcg, zinc 10 mg, and biotin 50 mcg once daily for 90 days increases time to ejaculation by about 29 seconds and improves control of ejaculation in about 60% of participants when compared to baseline. These improvements disappear within 90 days of discontinuing treatment. The validity of these findings is limited by the lack of a control group (96460).
• Sexual arousal. Although there has been interest in using oral rhodiola for improving sexual arousal, there is insufficient reliable information about the clinical effects of rhodiola for this condition.
• Stress. Preliminary clinical research suggests that oral rhodiola extract reduces feelings of stress. Details: Preliminary clinical research in adults with general stress shows that taking a specific dried rhodiola extract (Vitango, Schwabe Pharma) modestly reduces levels of stress in certain situations. Taking 200 mg twice daily before breakfast and lunch for 4 weeks improves stress, disability, and functional impairment when compared to baseline (90431). A small study in college students with anxiety shows that taking 200 mg twice daily for 14 days modestly reduces reported levels of stress, anxiety, anger, confusion, and negative mood when compared to a control group (96462). In adults experiencing symptoms of burnout, taking this specific extract 200 mg twice daily for 12 weeks modestly reduces perceived levels of stress, burnout, and fatigue and improves sexual satisfaction when compared to baseline. The validity of these findings is limited by the lack of a control group (96459). Rhodiola has also been evaluated in combination with other ingredients in individuals with stress. A small clinical study in healthy adults with chronic stress shows that taking a specific combination product (Mg-Teadiola, Sanofi-Aventis), containing rhodiola extract 222 mg, magnesium 150 mg, green tea extract 125 mg (providing theanine 50 mg), vitamin B6 0.7 mg, vitamin B9 0.1 mg, and vitamin B12 1.25 mcg, daily for 4 weeks reduces stress scores when compared with placebo (108672). It is unclear if these findings are due to rhodiola, other ingredients, or the combination.
• Tuberculosis. Although there has been interest in using oral rhodiola for tuberculosis, there is insufficient reliable information about the clinical effects of rhodiola for this condition.
• Upper respiratory tract infection (URTI). Although there has been interest in using oral rhodiola for URTI prevention, there is insufficient reliable information about the clinical effects of rhodiola for this purpose. More evidence is needed to rate rhodiola for these uses.

(Read more about RHODIOLA)

EFFECTIVE

• Vitamin C deficiency. Oral or intramuscular vitamin C is effective for preventing or treating vitamin C deficiency. Details: Administering vitamin C orally or intramuscularly prevents and treats vitamin C deficiency, including scurvy. Vitamin C administration can reverse complications of scurvy within 2 days to 3 weeks (4844). In newborns with transient tyrosinemia due to vitamin C deficiency, oral or intramuscular vitamin C can correct this condition (15).

POSSIBLY EFFECTIVE

• Anemia of chronic disease. Oral vitamin C seems to improve markers of anemia in patients on hemodialysis. Details: Meta-analyses of clinical research in hemodialysis patients with anemia shows that treatment with vitamin C 200-300 mg three times weekly for 3-6 months increases hemoglobin levels by approximately 0.9 grams/dL, increases transferrin saturation by about 8%, and decreases the required recombinant human erythropoietin dose by 17 U/kg weekly when compared with standard care (83447,83475).
• Atrial fibrillation. Oral and intravenous vitamin C seems to help prevent atrial fibrillation after cardiac surgeries. Details: Meta-analyses of clinical research show that taking vitamin C prior to and after cardiac surgery reduces the risk of postoperative atrial fibrillation by 27% to 53%. Most studies administered vitamin C at doses of 1-2 grams orally daily for 1-3 days prior to cardiac surgery, followed by 1-2 grams in two divided doses daily for 4-5 days after cardiac surgery. Some studies provided vitamin C intravenously at similar doses, but oral vitamin C seems to be more effective (91233,96703,96705). Despite these findings, a meta-analysis of clinical research conducted only in the U.S. does not support the benefit of vitamin C for reducing postoperative atrial fibrillation (96703). These differences may be related to lifestyle factors such as nutrition, as well as differences in hospital treatments. Vitamin C has also been studied in combination with eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) with evidence of benefit (90701).
• Bowel preparation. Powdered vitamin C is approved for use as part of a polyethylene glycol-based bowel preparation for colonoscopy. Details: Clinical research shows that treatment with 2 liters of oral solution containing polyethylene glycol (PEG) plus vitamin C achieves a similar quality of bowel cleansing as treatment with 4 liters of PEG when administered on the evening prior to colonoscopy or when administered in a split-dose regimen. Patients given 2 liters of PEG plus vitamin C solution also have better adherence and experience fewer adverse events, such as nausea, vomiting, or abdominal bloating, compared to patients treated with 4 liters of PEG solution without vitamin C (90413,90415,90420,90424,90428). This treatment also appears to be effective and tolerable in elderly patients aged 60-79 years, including those with poor bowel habits and a high number of comorbidities (108085). Other clinical research in older adults undergoing bowel preparation for colonoscopy also shows that taking 1 liter of PEG plus vitamin C (CleanViewAL, Taejoon Pharm) results in similar quality of bowel cleansing overall and per segment with similar tolerability and adverse effects as sodium picosulfate 170 mL plus magnesium citrate or oral sulfate solution alone (111297,112476). The most common PEG plus vitamin C preparation used in clinical research is MoviPrep (Norgine BV), which contains macrogol 3350 100 grams, sodium sulfate 7.5 grams, sodium chloride 2.7 grams, potassium chloride 1 gram, vitamin C 4.7 grams, and sodium ascorbate 5.9 grams per liter of solution (90413,90415,90424). In the U.S., MoviPrep is approved by the Food and Drug Administration (FDA) for bowel preparation prior to a colonoscopy.
• Cataracts. Dietary and supplemental intake of vitamin C may reduce the risk of developing cataracts. Details: Population research suggests that people with the highest total intake of vitamin C have about a 19% reduced risk of developing cataracts when compared with those with the lowest total intake, with the most benefit observed for nuclear cataracts (96711). Additionally, another observational study shows that higher supplemental intake of vitamin C over 10 years is associated with a 60% reduction in the incidence of nuclear and cortical cataracts (4208). Other population research suggests that individuals with the highest blood levels of vitamin C have a 33% lower odds of developing age-related cataract, but any benefit is limited to Asian populations (90944). An umbrella review of meta-analyses also shows that dietary intake of vitamin C is associated with a 27% lower odds of cataract development (112095). However, a prospective clinical study shows that a combination of vitamin C, vitamin E, and beta-carotene does not prevent age-related loss of vision from cataracts in well-nourished people with an average supplementation duration of 6.3 years (7304).
• Common cold. Oral high-dose vitamin C might modestly shorten and reduce cold symptoms; however, taking vitamin C prophylactically does not seem to prevent the development of a cold. Details: There is substantial controversy about the effectiveness of vitamin C for treating the common cold (1969,1989,7100,9835,9836). The majority of evidence shows that taking high doses of vitamin C orally might decrease the duration of cold symptoms by 1-1.5 days in some patients (1966,1967,1968,1987,6458,7102,9832,83487). However, other studies have found no effect with doses up to 3 grams daily (9833). A meta-analysis of clinical research in healthy children and adults shows that taking vitamin C 1-4 grams daily for one week to 5 months reduces cold severity by 13%, limits absences from daily activities, and improves the duration of severe symptoms, but does not reduce the duration of mild symptoms, when compared with placebo (113665). Vitamin C has also been investigated for preventing the common cold. A meta-analysis of clinical research suggests that vitamin C supplementation decreases the incidence of cold in individuals exposed to physical stress, but not in the general population (83487). Other research suggests vitamin C may be more effective for treating cold symptoms in children than in adults. Also, there may be a dose-dependent response; doses of at least 2 grams daily seem to work better than 1 gram doses (9834). Taking vitamin C supplements prophylactically does not decrease the risk of catching a cold (1966,1967,1968,1987,3042,6458,7101,9832). Dietary intake of vitamin C also does not seem to affect the risk of getting a cold (10780).
• Complex regional pain syndrome. Most research shows that taking oral vitamin C after a distal radius (i.e. wrist) fracture or surgery seems to reduce the risk of developing complex regional pain. However, it is unclear if oral vitamin C is beneficial in reducing the risk of complex regional pain in other orthopedic surgeries. Details: Although some research has found no benefit in patients with distal radius (i.e. wrist) fractures (90411,96702), most clinical research shows that taking vitamin C 500 mg daily, and possibly doses of up to 1500 mg daily, for 45-50 days beginning immediately after fracture can reduce the risk of developing complex regional pain syndrome (2045,16302,96700,96706). Reasons for discrepancies are unclear but might relate to differences in diagnostic criteria for complex regional pain syndrome (96702). Research in patients undergoing various orthopedic surgeries has also shown benefit with the use of vitamin C for the prevention of complex regional pain syndrome; however, some findings are conflicting. (90422,108076,115613). One meta-analysis of clinical research in patients undergoing ankle, foot, or wrist surgery shows that taking vitamin C 500-1000 mg for 42-50 days following surgery reduces the rate of complex regional pain syndrome, and may improve pain following ankle or foot surgery, when compared with placebo (108076). The validity of these findings is limited by the high heterogeneity of included trials. An additional meta-analysis of clinical research in patients undergoing a broader variety of orthopedic surgery types (i.e., ankle, foot, knee, shoulder, wrist) shows that taking vitamin C 500 to 1500 mg does not reduce the incidence of complex regional pain syndrome (115613). The reasons for these discrepant findings are unclear but may relate to the inclusion of a wide range of orthopedic surgeries.
• Exercise-induced respiratory infections. High-dose oral vitamin C seems to reduce the risk of respiratory infections associated with strenuous exercise. Details: Some preliminary clinical research suggests that prophylactic use of vitamin C in doses of 600 mg to 1 gram daily for 3-8 weeks before heavy physical exercise, such as a marathon, might prevent upper respiratory infections that sometimes follow heavy exercise (9831,83370). More recently, high doses of vitamin C have been studied. A large clinical study in army recruits undergoing basic military training shows that taking vitamin C 6 grams daily for one month reduces the odds of getting a cold by 20% when compared with placebo (102975).
• Hypercholesterolemia. Oral vitamin C seems to reduce lipid levels in patients with hypercholesterolemia. Details: A meta-analysis of clinical research in patients with hypercholesterolemia shows that taking vitamin C 500 mg daily for at least 4 weeks reduces low-density lipoprotein (LDL) cholesterol by about 8 mg/dL and reduces triglycerides by about 20 mg/dL when compared with control (83445).
• Hypertension. Oral vitamin C seems to modestly reduce blood pressure in patients with hypertension, but some evidence is conflicting. Details: Vitamin C seems to modestly reduce systolic blood pressure (SBP), without meaningful effects on diastolic blood pressure (DBP) (2044,9822,13162,83483,102974). A meta-analysis of 13 clinical trials in patients with hypertension, with or without other comorbidities, shows that taking a median dose of vitamin C 500 mg daily for 8 weeks reduces SBP but not DBP by about 5 mmHg. Some of the studies used vitamin C in combination with other supplements, such as vitamin E and magnesium. When studies assessing vitamin C alone were analyzed, the magnitude of reduction in SBP decreased (83483). A newer meta-analysis of small clinical studies in patients with essential hypertension shows that taking vitamin C 200 mg or more daily reduces SBP by about 4 mmHg and DBP by about 2 mmHg (102974). However, this newer analysis omitted numerous relevant studies and included studies with normotensive patients and those without an adequate control, limiting the validity of its findings. In contrast, a network meta-analysis of small, low-quality clinical studies comparing five different vitamins in adults with essential hypertension shows that vitamin C does not reduce SBP, DBP, mean 24-hour SBP, mean 24-hour DBP, or heart rate when compared with placebo and when indirectly compared with vitamin B2, vitamin D, vitamin E, and folic acid. However, the included studies were of low quality and high heterogeneity, particularly in dosing, limiting the validity of the results (113668).
• Laser skin resurfacing. Topical vitamin C seems to reduce erythema occurring after cosmetic laser skin resurfacing procedures intended to reduce scars and wrinkles. Details: There is some evidence that an aqueous formulation of topical vitamin C can decrease the degree and duration of erythema following cutaneous carbon dioxide laser resurfacing for scar and wrinkle removal (1959).
• Lead toxicity. Dietary vitamin C seems to lower concentrations of lead in the blood. Details: Observational research has found that consuming more vitamin C from dietary sources is associated with lower blood concentrations of lead. People who consumed at least 340 mg of vitamin C daily as part of the diet had lower blood lead levels than those who consumed less than 100 mg vitamin C daily (3097,3098,3099).
• Nitrate tolerance. Oral vitamin C might prevent nitrate tolerance in some patients. Details: Small clinical studies show that taking vitamin C orally seems to prevent the development of nitrate tolerance in patients taking sublingual nitroglycerin. There is some evidence that short-term vitamin C supplementation can prevent tolerance to the vasodilatory effects of nitrates (1441,1961).
• Postoperative pain. Oral or intravenous vitamin C might prevent acute postoperative pain following certain surgeries. It is unclear if vitamin C reduces chronic postoperative pain. Details: A meta-analysis of 7 small clinical studies in adults undergoing elective surgery shows that receiving perioperative vitamin C, either as 1 gram orally, 2-3 grams intravenously, or 50 mg/kg intravenously, modestly reduces acute pain and opioid requirements for up to 24 hours when compared with control (105457). Most surgeries were laparoscopic and included cholecystectomy, colectomy, hysterectomy; two non-laparoscopic surgeries included uvulopalatopharyngoplasty with tonsillectomy and major abdominal surgery (90418,99840,105457). A meta-analysis of clinical trials in adults undergoing noncardiac surgery (i.e., orthopedic, abdominal, gynecologic, kidney transplantation) shows that administering perioperative vitamin C, either orally or intravenously, reduces postoperative intravenous morphine requirements at 2, 24, and 48 hours after surgery and improves pain scores at 2, 6, and 24 hours after surgery when compared with placebo. The dose of vitamin C did not appear to impact outcomes. However, when only laparoscopic surgeries are included, perioperative vitamin C does not improve pain or morphine use when compared with placebo (108087). Use of vitamin C perioperatively has also been evaluated in other surgery types with generally similar outcomes. A moderate-sized clinical study in adults undergoing total hip arthroplasty shows that intravenous vitamin C 3 grams perioperatively reduces 24-hour post-operative morphine use and subjective pain scores when compared with placebo; however, these improvements do not appear to be clinically significant (115500). The validity of these results is limited by a short follow-up period. Additionally, a small observational study in adults undergoing surgery for wisdom tooth extraction shows that taking vitamin C 500 mg three times daily for 7 days in addition to standard treatment reduces pain 24, 48, and 72 hours after surgery when compared with control (113664). However, a moderate-sized clinical study in adults undergoing transurethral resection of a bladder tumor under general anesthesia shows that administering intravenous vitamin C 1 gram after induction of anesthesia reduces the incidence and severity of catheter-related bladder discomfort immediately after surgery and at 1 and 2 hours postoperatively, but not 6 hours, when compared with placebo. Further, vitamin C does not reduce postoperative pain scores or analgesic requirements when compared with placebo (111645). Vitamin C has also been evaluated for reducing chronic pain after surgery. Clinical research in patients undergoing surgery for foot or ankle trauma shows that taking vitamin C 500 mg orally twice daily postoperatively for 6 weeks reduces pain scores when compared with placebo at 2 weeks and 6 weeks. The mean total amount of diclofenac used for pain relief over the 6-week period is also reduced, from 5.7 grams with placebo to 3.4 grams with vitamin C (102131).
• Wrinkled skin. Topical vitamin C might reduce the appearance of existing wrinkles. Details: Topical preparations containing vitamin C seem to improve the appearance of wrinkled skin. Some evidence shows that vitamin C 3% applied for 12 weeks might reduce facial wrinkles (14008). A small clinical study shows that applying a dissolving microneedle patch containing vitamin C 5.6% every 4 days for 12 weeks to crow's feet on one side of the face reduces wrinkles when compared to control treatment applied on the other side of the face (98780). Other clinical research in females aged 30-60 years shows that applying an oil-soluble cream containing the vitamin C derivative tetra-isopalmitoyl ascorbic acid 1%, 2%, or 3% to the periorbital area twice daily for 8 weeks reduces visual wrinkle grading when compared with placebo. A dose analysis shows greater improvements in wrinkle parameters, average wrinkle depth, and mean depth with the lower concentration, while greater improvements in maximum roughness and maximum depth are observed with the higher concentration (108072). This study only included individuals defined as having Fitzpatrick skin type III or IV; it effects on other skin types is unclear. Preparations containing vitamin C in combination with other ingredients have also been investigated. A small low-quality trial in females with moderately photodamaged and hyperpigmented facial skin shows that applying a moisturizer with vitamin C 30%, vitamin E, and coenzyme Q10 once daily in the morning, along with applying retinol 0.5% once daily or once every other day for 12 weeks, seems to improve skin tone, photodamage, and wrinkles when compared to baseline (99085). In another small trial, a topical preparation containing vitamin C 10% as L-ascorbic acid along with acetyl tyrosine, zinc sulfate, sodium hyaluronate, and bioflavonoids (Cellex-C High Potency Serum) applied to photo-aged facial skin for 3 months improves fine and coarse wrinkling, yellowing and sallowness, roughness, and skin tone when compared with placebo (6155). It is unclear if the beneficial effects of these products are due to vitamin C, other ingredients, or the combination.

POSSIBLY INEFFECTIVE

• Acute bronchitis. Oral vitamin C doesn't seem to improve symptoms of acute bronchitis. Details: A clinical study in adults with acute bronchitis shows that taking vitamin C orally 500 mg on day 1, then 250 mg on days 2 through 5 (similar to an azithromycin regimen) doesn't seem to have any effect on quality of life or bronchitis duration when compared with azithromycin (9827).
• Asthma. Oral vitamin C doesn't seem to prevent asthma or improve lung function. Details: Although some observational research has found that some patients with asthma might have lower serum vitamin C levels (5873), other observational research found that increased dietary vitamin C intake is not associated with a reduced risk of asthma or improved lung function (15006,34567). In addition, clinical research shows that supplemental intake of vitamin C does not reduce asthma symptoms, improve lung function, or reduce the use of inhaled steroids in asthma patients (90409).
• Atherosclerosis. Oral vitamin C does not seem to reduce the progression of atherosclerosis. Details: A clinical study shows that taking a specific combination product containing slow-release vitamin C 250 mg and vitamin E 136 IU (CellaVie, Ferrosan A/S) twice daily modestly slows the 3-year progression of atherosclerosis of the carotid artery in males, but not females. This result persisted at a 6-year follow-up of this study (1918,10473). However, when this form of vitamin C is used alone, it does not slow the 3-year progression of atherosclerosis of the carotid artery (1918).
• Bladder cancer. Oral vitamin C does not reduce the risk of bladder cancer or mortality from bladder cancer. Details: Epidemiological research has found that supplemental vitamin C intake is not associated with mortality rate in patients with bladder cancer (9839). A secondary analysis of a large clinical trial, the Physicians' Health Study II, in healthy men aged at least 50 years also shows that taking vitamin C 500 mg daily alone or with vitamin E 400 IU daily for up to 10 years does not reduce the risk of developing bladder cancer or bladder cancer-related deaths when compared with placebo (90097).
• Cardiovascular disease (CVD). Oral vitamin C does not seem to be beneficial for either primary or secondary CVD prevention. Details: Vitamin C does not seem to be beneficial for primary prevention of CVD. Some population research has found that higher supplemental vitamin C or dietary vitamin C has been associated with a reduced risk of developing CVD (10358,14108,109779), while other observational research has found no benefit (34566,10358,14108). However, meta-analyses of clinical research in healthy patients show that vitamin C supplementation does not prevent CVD or coronary heart disease when compared with control (97308,104025). In 2004, the American Heart Association stated that current evidence does not justify use of antioxidants such as vitamin C for reducing the risk of CVD (12142). Evidence is also negative for secondary prevention in people with coronary heart disease. Population studies have found that higher serum vitamin C was associated with no effect or decreased CVD mortality from CVD (3910,5878). A meta-analysis of two large clinical trials shows that vitamin C supplementation does not reduce CVD events or CVD mortality when compared with control (97308).
• Colorectal cancer. Oral vitamin C does not seem to prevent colorectal cancer. Details: Population research has found that dietary vitamin C intake is not associated with a reduced risk of developing colon cancer. When total vitamin C intake from food and supplements is considered, there is a modest association (34600). However, most clinical trials show that supplemental vitamin C, alone or along with other antioxidants, does not reduce the risk of colorectal cancer development, colorectal cancer or adenoma recurrence, or colorectal cancer-related mortality (34580,34581,34594,90097,90089,92903).
• Fetal and premature infant mortality. Oral vitamin C does not seem to prevent neonatal death. Details: Meta-analyses of clinical research show that taking vitamin C alone or with other supplements does not reduce the risk of neonatal death (83472,96707).
• Fractures. Oral vitamin C does not seem to improve fracture healing. Details: Clinical research shows that taking vitamin C 500 mg daily for 50 days following an acute distal radial fracture does not improve physical function, symptoms, or healing rates when compared with placebo (90411).
• Helicobacter pylori. Oral vitamin C does not seem to improve eradication of H. pylori. Details: Most clinical research shows that treatment with vitamin C, alone or in combination with vitamin E, does not improve the eradication rate of H. pylori when taken with a standard eradication regimen when compared with the eradication regimen alone (83476,90094).
• Hereditary motor and sensory neuropathy. Oral vitamin C does not seem to improve neuropathy in these patients. Details: In a meta-analysis of five studies in patients with Charcot-Marie-Tooth disease type 1A, taking vitamin C 1-4 grams orally daily for 1 year did not improve neuropathy when compared with placebo (99084). Continuing vitamin C 4 grams daily for 2 years also does not improve neuropathy in these patients (90419).
• Interferon-related retinopathy. Oral vitamin C does not seem to improve retinopathy associated with interferon therapy. Details: A small clinical study in patients with chronic hepatitis C receiving interferon therapy shows that taking vitamin C 600 daily orally does not seem to reduce the risk of retinopathy from interferon therapy when compared with control (10355).
• Leukemia. Oral vitamin C does not seem to reduce the risk of leukemia or mortality from leukemia. Details: A large clinical trial in men aged at least 50 years shows that taking vitamin C 500 mg daily, alone or along with vitamin E 400 IU daily, for up to 10 years does not reduce the risk of developing leukemia or leukemia-related deaths when compared with placebo (90097).
• Low birth weight. Oral vitamin C does not seem to reduce the risk of infants being born with a low birth weight. Details: Meta-analyses of clinical research show that maternal use of oral vitamin C alone or with other supplements does not reduce the risk of giving birth to infants with low birth weight when compared with control (83450,83472).
• Lung cancer. Oral vitamin C does not seem to reduce the risk of lung cancer. Details: Two meta-analyses of clinical research suggest that taking vitamin C, alone or in combination with vitamin E, does not reduce the incidence of lung cancer or lung cancer-related mortality (34528,34632). Also, a clinical study in females shows that taking supplemental vitamin C 500 mg daily, with or without vitamin E and beta carotene, is associated with an INCREASED risk of lung cancer when compared with placebo (34580). However, another large epidemiological cancer screening trial with a mean follow-up of over 12 years suggests that moderate dietary intake of vitamin C around 500 mg daily is protective against lung cancer, but higher doses of vitamin C might increase the risk of lung cancer (112096).
• Melanoma. Oral vitamin C does not seem to reduce the risk of melanoma. Details: Clinical research shows that taking vitamin C 500 mg daily, alone or along with vitamin E 400 IU daily, for up to 10 years does not reduce the risk of developing melanoma or melanoma-related deaths when compared with placebo in men aged at least 50 years (90097).
• Miscarriage. Oral vitamin C does not seem to reduce the risk of miscarriage. Details: A meta-analysis of clinical research shows that taking vitamin C alone or with other supplements does not reduce the risk of miscarriage when compared with control (94820).
• Overall mortality. Oral vitamin C does not reduce overall mortality. Details: Although population research suggests that higher dietary intake and higher plasma vitamin C levels are associated with a reduced risk of mortality from all causes (3910,109779), vitamin C supplementation does not seem to affect overall mortality. Meta-analyses of clinical research show that taking vitamin C supplements does not reduce overall mortality when compared with control (34622,111641). Clinical studies of vitamin C used in combination with vitamin E, beta carotene, and/or selenium and zinc, also show no benefit for overall mortality (9817,14109).
• Pancreatic cancer. Oral vitamin C does not seem to prevent pancreatic cancer. However, it is unclear if intravenous vitamin C is beneficial for treatment of pancreatic cancer. Details: Observational research has found that increased dietary vitamin C intake is associated with up to a 30% reduced risk of pancreatic cancer (99083,99086). However, clinical research shows that supplemental vitamin C 500 mg daily does not reduce the risk of pancreatic cancer in females (34580). Also, taking vitamin C in combination with beta-carotene plus vitamin E does not reduce the risk of pancreatic cancer (12185,34581). While research suggests oral vitamin C may not prevent pancreatic cancer, intravenous vitamin C is being explored in the treatment of pancreatic cancer. A small, open-label clinical study in adults with stage IV pancreatic ductal adenocarcinoma shows that administration of intravenous vitamin C 75 grams three times weekly throughout each cycle of chemotherapy increases median overall survival and progression free survival by approximately 8 months and 2 months, respectively, when compared with chemotherapy alone (115499). The validity of these results is limited by potential overestimation of treatment effects, influenced by small sample size, differences in chemotherapy doses, and early study termination.
• Pre-eclampsia. Oral vitamin C does not seem to prevent pre-eclampsia. Details: Despite some early positive research in high-risk pregnancies, the majority of meta-analyses and clinical studies show that taking vitamin C alone or with vitamin E or other supplements does not reduce the risk of pre-eclampsia when compared with control. There is even some concern that vitamin C supplementation may increase the risk of gestational hypertension (3236,83450,83472,83474,96707).
• Preterm labor. Oral vitamin C does not seem to prevent preterm labor. Details: Meta-analyses of clinical research show that taking vitamin C alone or with other supplements does not reduce the risk of preterm labor when compared with control (83450,83472,96707).
• Prostate cancer. Oral vitamin C does not seem to prevent prostate cancer. However, it is unclear if intravenous vitamin C is beneficial for the treatment of prostate cancer. Details: A large-scale clinical study (The SU.VI.MAX study) shows that a combination of vitamin C 120 mg, vitamin E (alpha-tocopherol) 30 mg, beta-carotene 6 mg, selenium 100 mcg, and zinc 20 mg, taken daily for an average of 8 years, does not reduce the risk of prostate cancer overall. However, it might reduce the risk of prostate cancer in those who have normal PSA levels. It does not seem to be beneficial for reducing the risk of prostate cancer in patients with PSA levels above 3 mcg/L (14135). Another large scale study (Physician's Health Study II) shows that taking vitamin C 500 mg daily for an average of 8 years does not significantly reduce the risk of prostate cancer when compared with placebo (16708). Similarly, results from the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial seem to show that supplemental or dietary intake of vitamin C does not reduce the risk of prostate cancer when compared to individuals not taking vitamin C (14124). While research suggests oral vitamin C may not prevent prostate cancer, intravenous vitamin C is being explored in the treatment of prostate cancer. A small clinical study in adults with metastatic castration-resistant prostate cancer shows that administration of intravenous vitamin C 1 gram/kg twice weekly in combination with docetaxel for up to 24 weeks does not reduce prostate-specific antigen (PSA) by 50% or more when compared with docetaxel alone (115611). This study may have been underpowered to show a difference between groups.
• Radiation dermatitis. Topical vitamin C does not seem to prevent radiation dermatitis in cancer patients. Details: A small clinical study shows that applying a 10% vitamin C solution does not appear to protect from radiation dermatitis when applied to the scalps of patients treated with radiation for intracranial tumors (789).
• Small for gestational age (SGA). Oral vitamin C does not seem to reduce SGA. Details: Meta-analyses of clinical research show that taking vitamin C alone or with other supplements does not reduce the risk of small for gestational age birth when compared with control (83450,83472).
• Stillbirth. Oral vitamin C does not seem to prevent stillbirth. Details: Meta-analyses of clinical research show that maternal use of vitamin C alone or with other supplements does not reduce the risk of stillbirth when compared with control (83472,96707).

LIKELY INEFFECTIVE

• Coronavirus disease 2019 (COVID-19). Oral vitamin C, even at high doses, does not seem to speed recovery from COVID-19 in non-hospitalized patients. Most studies show that oral or intravenous vitamin C given to patients hospitalized with COVID-19 does not improve organ function or survival, but the evidence is conflicting. It is unclear whether vitamin C is beneficial for long COVID. Details: A clinical study in adult outpatients with confirmed COVID-19 shows that taking oral vitamin C (ascorbic acid) 8000 mg in 2-3 divided doses daily, alone or with zinc gluconate 50 mg daily, for 10 days does not reduce symptom severity when compared with standard care (104450). The study was terminated prior to complete enrollment due to futility and apparent lack of effect from vitamin C and/or zinc supplementation. Limitations of this study include a lack of placebo control and blinding. Additionally, this study has been criticized for methodologic concerns (106624). Another small clinical trial in adult outpatients with confirmed COVID-19 shows that taking vitamin C 1000 mg daily for 14 days does not improve symptoms or quality of life when compared with placebo (109462). Vitamin C has also been evaluated in patients hospitalized with COVID-19. A very large analysis of two multinational clinical studies in critical and non-critical adults hospitalized with COVID-19 shows that administering intravenous vitamin C 50 mg/kg every 6 hours for 96 hours does not improve organ support-free days or survival and has a high probability of futility and worsened outcomes when compared with placebo (113666). Individual prospective and retrospective studies in critically ill patients hospitalized with COVID-19 in various countries have found that administering vitamin C, either enterally as 500-1000 mg daily or intravenously as 8-24 grams daily or 50 mg/kg daily, does not significantly reduce in-hospital or short-term mortality, hospital length of stay, or end-organ failure when compared with control groups receiving standard care alone. Additionally, all but one study found no change in the need for mechanical ventilation (105458,105465,106937,106938,108075,108079,108081). However, a meta-analysis and some small individual studies have found that vitamin C is modestly beneficial for patients hospitalized with COVID-19. A meta-analysis of 10 clinical trials and 9 observational studies in patients hospitalized with COVID-19 shows that receiving oral or intravenous vitamin C daily reduces the odds of in-hospital mortality by 41% when compared with control. When only clinical trials were considered, the odds of in-hospital mortality were decreased by 56%; however, this reduction was only identified in studies using vitamin C 10 grams daily or less. Conversely, supplementation with vitamin C increased the length of intensive care unit (ICU) stay by nearly 2 days and did not impact length of hospital stay or reduce the need for mechanical ventilation, liver injury, or cardiac injury (109955). Similarly, a meta-analysis of 8 clinical studies in primarily hospitalized patients with moderate to severe COVID-19 shows that vitamin C administered orally or intravenously decreases the risk of all-cause mortality by 16% when compared with control (114488). Additionally, a small study found a small improvement in survival when compared with standard care; however, the overall survival rate in this study was low (108075). Another clinical study in patients hospitalized in Turkey with COVID-19 shows that adding high-dose intravenous sodium ascorbate 50 mg/kg to a treatment regimen of hydroxychloroquine, azithromycin, and zinc may improve recovery time, with 57% and 39% of patients achieving total recovery at day 15 in the vitamin C and control groups, respectively (108071). However, the validity of this trial is limited due to unclear reporting. Vitamin C has also been evaluated in combination with other ingredients in patients with long COVID. Preliminary clinical research in adults with long COVID and persistent fatigue shows that taking a specific combination product containing vitamin C 500 mg and L-arginine 1.66 grams (Bioarginina C, Farmacetici Damor) for 28 days increases 6-minute walk test distance by 10% and reduces self-reported fatigue when compared with placebo (110390). However, it is unclear whether these effects are due to vitamin C, L-arginine, or the combination.
• Sepsis. Intravenous vitamin C, alone or in combination with thiamine and/or hydrocortisone, does not prevent organ failure, reduce intensive care or hospital length of stay, or reduce mortality in sepsis or septic shock. Details: Observational research suggests that patients with septic shock are more likely to have low plasma levels of vitamin C (100317). However, three randomized clinical trials in patients with sepsis or septic shock show no benefit with intravenous vitamin C, with or without thiamine, for improving organ function and preventing organ failure when compared with control treatment (102130,104027,114489). A small clinical study in patients with septic shock shows that intravenous vitamin C 50 or 150 mg/kg daily for 4 days does not improve organ dysfunction or failure rates, duration of hospital or intensive care unit (ICU) length of stay, duration of mechanical ventilation, or mortality rate when compared with placebo (114489). Another clinical study in patients with septic shock shows that administering an intravenous bolus of vitamin C 1000 mg followed by a continuous infusion of 250 mg/hour for 96 hours, starting within 24 hours of vasopressor initiation, does not improve 28-day or ICU mortality when compared with placebo. A subgroup analysis shows that the addition of corticosteroids does not affect outcomes in either group (108078). This study may have been inadequately powered to detect a difference between groups. Also, a larger clinical trial in adults with sepsis receiving vasopressor therapy in the ICU shows that intravenous administration of vitamin C 50 mg/kg every 6 hours for up to 4 days increases the risk of death or persistent organ dysfunction at day 28 by 14% to 21% when compared with placebo. There were no differences in mortality at 6 months (109459,111643). Vitamin C has also been frequently studied in patients with sepsis and septic shock in a specific combination regimen (HAT therapy) which includes intravenous vitamin C 1.5-2 grams with hydrocortisone 50 mg every 6 hours and thiamine 200 mg every 12 hours. While some retrospective research has found HAT therapy to be beneficial in sepsis (100315,102980), high quality, prospective clinical research has not confirmed these findings (105447,106620,109956). Several meta-analyses of randomized controlled trials and small clinical studies in patients with sepsis or septic shock show that intravenous vitamin C, either alone, as a component of HAT therapy, or in combination with thiamine, does not reduce short- or long-term mortality, ICU or hospital length of stay, kidney injury, or duration of mechanical ventilation, but modestly improves duration of vasopressor use and procalcitonin clearance, when compared with placebo or standard care. These analyses also show mixed results with respect to improvement in sequential organ failure assessment (SOFA) scores within 72 hours (105447,106620,106935,108073,109460,111298,111300,111301,111642,112479). Most studies included in the analyses administered HAT therapy for 2-10 days and compared it with normal saline control or with hydrocortisone alone (102129,102998,104027,104028,104032,105446). Although some subgroup analyses suggests that intravenous vitamin C alone in patients with sepsis may improve short-term mortality (106620,111298), other meta-analyses have not shown this benefit in subgroup analyses (111300). In addition, meta-analyses have identified significant publication bias (111298,111300). Long-term follow up from a study in patients with sepsis-induced respiratory and/or cardiovascular dysfunction shows that receiving HAT therapy does not improve cognitive, psychological, or functional status after 6 months and, for some domains, HAT therapy was worse when compared with placebo (111299). Studies evaluating intravenous vitamin C, either alone, as a component of HAT therapy, or in combination with thiamine, in mixed critically ill populations have also shown mixed findings. Four meta-analyses of randomized controlled trials and observational studies show that intravenous vitamin C does not have a significant effect on the length of hospital stay, mortality at 1 month, ICU mortality, use of invasive ventilation, use of renal replacement therapy, organ function, or incidence of kidney injury when compared with placebo or standard care. The meta-analyses reach conflicting conclusions on whether intravenous vitamin C reduces the risk of in-hospital mortality, 30-day mortality, and the duration of ICU stay. When only data from low risk-of-bias clinical trials are considered, the effects of intravenous vitamin C on mortality at any point are no longer significant (106933,106934,109957,113663). However, a subgroup analysis in one of these analyses suggests that intravenous vitamin C as monotherapy, or in doses of at least 10 grams daily, may improve overall mortality (106934). Vitamin C also does not appear to benefit complications from sepsis, such as vasoplegic shock. A small clinical study in adults in the ICU with vasoplegic shock mostly secondary to sepsis and requiring moderate vasopressor support shows that administering intravenous vitamin C as sodium ascorbate 1.5 grams every 6 hours for 5 days or until cessation of vasoactive therapy does not reduce the duration of vasopressors, vasopressor dose, hospital or ICU length of stay, or mortality outcomes when compared with placebo (112475).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Atrophic acne scars. It is unclear if applying topical vitamin C after microblading improves atrophic acne scars. Details: A clinical study in adults with mild to severe atrophic acne scarring shows that applying a serum containing vitamin C 17% to the face after a once-monthly home microblade treatment for 4 months improves the appearance of acne scars at month 5 when compared with baseline (108086). Although this study enrolled a control group that used topical insulin in place of vitamin C, no between-group statistical comparisons were conducted, limiting the validity of this study.
• Age-related macular degeneration (AMD). It is unclear if dietary vitamin C or oral vitamin C taken in combination with other ingredients prevents AMD. Details: An umbrella review of meta-analyses shows that increased dietary intake of vitamin C is associated with 21% higher odds of developing AMD (112095). A population study suggests that vitamin C intake is associated with increased odds of developing age-related maculopathy (9823). However, other population studies have found no association between dietary or supplemental vitamin C intake and the risk of developing AMD (14007,14257). When taken in combination with other ingredients, most clinical and population research shows that taking vitamin C 500 mg along with other antioxidants such as vitamin E 400 IU, beta-carotene 15 mg, and/or elemental zinc 80 mg reduces the risk of visual acuity loss by 23% to 27%, progression to advanced AMD at 5 years by 25% to 32%, and AMD overall (7303,7304,11326,14257,90069). The antioxidant plus zinc combination seems to reduce the risk of progression to advanced AMD in these patients more than taking the antioxidants without zinc (7303,90069). More evidence is needed to determine what role, if any, vitamin C intake has on the risk of developing AMD.
• Aging skin. Topical vitamin C has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Clinical research in females aged 30-65 years shows that applying a specific liquid (Antioxidant and Collagen Booster Serum, Max Biocare Pty Ltd.) containing vitamin C 20%, red raspberry leaf cell culture extract 0.0005%, and vitamin E 1% to the face nightly for 8 weeks, in addition to regular facial skin products, improves skin color, elasticity, radiance, smoothness, and appearance of wrinkles when compared with regular facial skin products alone (102355).
• Albuminuria. Oral vitamin C has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study shows that taking vitamin C 1250 mg plus vitamin E 680 IU daily for 4 weeks can reduce the excretion of albumin by about 19% when compared with placebo in patients with type 2 diabetes (10434).
• Allergic rhinitis (hay fever). It is unclear if oral vitamin C is beneficial in patients with hay fever. Details: Epidemiological research has found that higher vitamin C plasma levels are not associated with a decreased risk of allergic rhinitis (15200). However, clinical research shows that some forms of vitamin C might help. In one small clinical study, intranasal vitamin C administered three times daily for 2 weeks reduces nasal secretions, nasal blockage, and edema in up to 74% of patients with perennial allergic rhinitis (15201). Another small clinical study in patients with seasonal allergic rhinitis shows that taking a single oral dose of vitamin C 2 grams reduces bronchial responsiveness to histamine at one hour after ingestion (15202). However, in another small study in patients with seasonal allergic rhinitis taking vitamin C orally in doses up to 4 grams daily for 3 days does not appear to suppress cutaneous or nasal response to histamine when compared to placebo (15203).
• Alzheimer disease. It is unclear if dietary vitamin C helps to prevent this condition. Details: Most epidemiological research has found that dietary intake of vitamin C is associated with a 17% reduced risk of developing Alzheimer disease (4636,9824,10131,13165,90082).
• Amyotrophic lateral sclerosis (ALS, Lou Gehrig's disease). It is unclear if oral vitamin C helps to prevent ALS. Details: Observational research has found that increased dietary or supplemental intake of vitamin C is not associated with risk of developing ALS (90412).
• Anthracycline cardiotoxicity. Although there is interest in using oral vitamin C for anthracycline-induced cardiac toxicity, there is insufficient reliable information about the clinical effects of vitamin C for this condition.
• Aspirin-associated gastric damage. It is unclear if oral vitamin C helps to prevent gastric damage caused by aspirin. Details: Some clinical research shows that vitamin C 480 mg might prevent gastric damage associated with taking aspirin 400 mg by decreasing blood loss and preventing decreased gastric blood flow (10357). However, a small clinical study in healthy patients shows that taking vitamin C 500 mg as ascorbic acid with aspirin 600 mg actually increases gastrointestinal permeability to a greater extent than either ingredient taken alone (98781).
• Athletic performance. It is unclear if oral vitamin C improves athletic performance. Details: Although some small preliminary clinical studies suggest that vitamin C might improve certain biomarkers during exercise (82922), a meta-analysis of small clinical trials in older and younger adults shows that taking vitamin C 500-1000 mg daily, with or without vitamin E, does not improve endurance, lean mass, or muscle strength when compared with placebo (102973). A more recent, small clinical study in recreationally trained males shows that taking vitamin C 1000 mg and vitamin E (as alpha-tocopherol) 235 mg daily for 10 weeks while participating in a resistance training program does not improve measures of muscle strength when compared with placebo (109959).
• Atopic disease. It is unclear if dietary vitamin C helps to prevent atopic disease. Details: Population research has found that higher intake of vitamin C is not associated with a reduced risk of eczema, wheeze, IgE-mediated food allergy, or allergic sensitization (90098).
• Attention deficit-hyperactivity disorder (ADHD). Small clinical studies suggest that high-dose oral vitamin C may not improve symptoms in patients with ADHD. Details: Some research suggests that taking megadose vitamins, including vitamin C, does not improve ADHD symptoms (9957,9958,9959). However, other preliminary clinical research shows that taking 25 mg of vitamin C in combination with flaxseed oil providing alpha-linolenic acid 200 mg twice daily might improve measures of attention, impulsivity, restlessness, and self-control in children with ADHD when compared with baseline (14443). It is not clear if these effects are due to vitamin C, flaxseed oil, or the combination.
• Autism spectrum disorder. It is unclear if oral vitamin C is beneficial in patients with autism spectrum disorder. Details: One small clinical study shows that taking vitamin C 8 grams per 70 kg daily for 10 weeks modestly reduces autism symptom severity in school children when compared with placebo (83604).
• Bleeding. It is unclear if intravenous vitamin C can reduce bleeding after total abdominal hysterectomy. Details: A small clinical study in patients undergoing total abdominal hysterectomy shows that administration of intravenous vitamin C 1 gram the night before surgery and 1 gram during surgery reduces postoperative hemorrhage volume by around 40 mL when compared with placebo (109465).
• Brain tumor. It is unclear if oral vitamin C helps to prevent brain tumors. Details: Population research has found that vitamin C intake is associated with a 14% reduced risk of glioma. This risk reduction was more prevalent in America compared to other geographic locations (98782).
• Breast cancer. It is unclear if oral vitamin C helps to prevent breast cancer, its recurrence, or breast cancer-related mortality. Details: Some epidemiological research has found that dietary vitamin C is associated with a reduced risk of breast cancer (1444,10823,10824). However, other epidemiological research has found no association with dietary or supplemental vitamin C (10825,10826,108080). One cohort study found no association between breast cancer risk and total, dietary, or supplemental vitamin C, regardless of dose, treatment duration, or formulation (single ingredient or combination product). Additionally, hormone and menopausal status did not appear to impact risk. Vitamin C intake might be associated with a reduced risk in individuals with a family history of breast cancer in first-degree relatives (108080). In patients with breast cancer, supplemental or dietary intake of vitamin C might be associated with a reduced risk of mortality. A meta-analysis of results from population research shows that vitamin C supplementation following breast cancer diagnosis is associated with a 15% lower risk of breast cancer-related mortality when compared with no supplementation (90416). A large, observational study in patients with breast cancer undergoing radiation therapy has found that vitamin C supplementation does not reduce the risk of breast cancer recurrence over a period of 5 years when compared with no supplementation. Although the vitamin C group had notably less aggressive tumor types, recurrence-free survival was similar in both vitamin C and control groups (108082). The validity of these findings is limited due to unknown doses of vitamin C and the inclusion of various breast cancer subtypes.
• Burns. Small studies suggest that intravenous vitamin C may modestly improve symptoms in patients with severe burns. Details: A small clinical study in patients with severe burns shows that administering vitamin C intravenously (IV) 66 mg/kg hourly over 24 hours, as part of fluid resuscitation using lactated ringer solution, reduces wound edema and the volume of fluid needed when compared with fluid resuscitation alone (83145). A retrospective review of adults hospitalized with severe burns has found that those who receive a continuous IV infusion of at least 10 grams of vitamin C within 2 days of admission have an in-hospital mortality rate of 46%, compared with 58% for those who do not receive vitamin C (102128).
• Cancer. It is unclear if oral or intravenous vitamin C helps to prevent cancer or cancer-related mortality. Details: Some population research has found that DIETARY intake of vitamin C is linked with a lower risk of cancer and cancer-related mortality (3910,5878,10819,109779). However, clinical research shows that taking vitamin C SUPPLEMENTS does not reduce the risk for cancer (10819,14109,34580,90097). In people with cancer, although some clinical research has shown that taking high-dose vitamin C supplements can improve survival rates (9809,96704), other clinical research has not shown this benefit (4842,4843). In 2003, the US Food and Drug Administration (FDA) determined that it would allow a qualified health claim stating that some scientific evidence suggests that antioxidant vitamins, such as vitamin C, may reduce the risk of certain forms of cancer. However, the FDA has determined that there is little scientific evidence supporting this claim (102334). Preliminary clinical research has also evaluated vitamin C supplements in patients with cancer. High-dose oral vitamin C, 10 grams daily, in patients with advanced cancer does not seem to improve survival or decrease disease progression (4842,4843,106617). However, preliminary clinical research suggests high doses of vitamin C, given intravenously, might have a beneficial effect on some outcomes, including survival rate in some patients with cancer (9809,96704,106617). However, there is no benefit to other patients studied in the case reports and this has not been tested in well-designed clinical trials (9809,96704).
• Cardiac arrest. It is unclear if intravenous vitamin C is beneficial for patients after cardiac arrest. Details: A small clinical study conducted in Slovenia in adult survivors of out-of-hospital cardiac arrest shows that administering intravenous vitamin C 1.5 grams every 12 hours for 8 consecutive doses, with the first dose administered within 6 hours of resuscitation, in addition to standard care protects against arrhythmias and reduces the length of intensive care unit (ICU) stay when compared with placebo and standard care. However, intravenous vitamin C does not appear to protect against neurological or myocardial injury, reduce the need for mechanical ventilation, reduce the duration of hospital stay, or increase survival when compared with placebo (113667).
• Carpal tunnel syndrome. Vitamin C has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A clinical study in adults with mild to moderate carpal tunnel syndrome shows that taking a combination product containing vitamins C, E, B1, B2, B6, and B12, alpha-lipoic acid, acetyl-L-carnitine, phosphatidylserine, and turmeric twice daily for 60 days reduces symptom severity and pain but does not improve measures of hand and wrist function when compared with control (111702). The validity of these effects is limited by a lack of blinding. The study may also be inadequately powered to detect a difference between groups. Additionally, it is unclear if the effects are due to vitamin C, other ingredients, or the combination.
• Cervical cancer. It is unclear if oral vitamin C helps to prevent cervical cancer. Details: Observational research has found that higher vitamin C intake is associated with a 33% to 42% reduced odds of cervical neoplasm. Increasing vitamin C intake by 50 mg daily is associated with an 8% reduced odds of cervical neoplasm (34609,98771).
• Child growth. Some clinical research in pregnant smokers suggests that taking vitamin C during pregnancy may improve pulmonary function in the offspring from birth to 6 years of age. Details: A meta-analysis of 4 data sets from one large clinical study in pregnant adults who smoke at least one cigarette daily shows that taking supplemental vitamin C 500 mg daily during pregnancy reduces lower airway resistance and improves lung capacity of the offspring at 0, 3, 12, and 60 months of age, but does not improve airway obstruction, when compared with control (113670). Additionally, one of the clinical studies included the meta-analysis shows that taking vitamin C during pregnancy lowers the occurrence of wheezing in offspring at 4-6 years of age (114496,114497).
• Chronic fatigue syndrome (CFS). Although there is interest in using oral vitamin C for CFS, there is insufficient reliable information about the clinical effects of vitamin C for this condition.
• Colistin-induced nephrotoxicity. It is unclear if intravenous vitamin C helps to prevent nephrotoxicity from colistin. Details: A small clinical study shows that intravenous administration of vitamin C 2 grams every 12 hours along with colistin for around 9-10 days does not prevent nephrotoxicity when compared with colistin therapy alone (99839). However, this study was limited by a lack of statistical power to detect differences between the study groups.
• Contrast induced nephropathy. It is unclear if oral vitamin C helps to prevent contrast-induced nephropathy (CIN). Details: Some clinical research shows that taking vitamin C before and after coronary angiography reduces the risk of developing CIN by 33% to 55% when compared with placebo in patients with renal dysfunction (12234,90421). However, other clinical evidence published since 2012 suggests that vitamin C given orally and/or intravenously before and after angiography does not reduce the risk of CIN compared with control in high-risk patients with chronic renal insufficiency or diabetes (91232,91236,90410,90425). Reasons for the discrepancies are not entirely clear. However, it is possible that the lack of significant benefit from vitamin C in the latter studies results from the fact that incidences of CIN have become less common than in the past due to avoidance of dehydration, use of smaller catheters, and use of contrast agents with reduced nephrotoxicity (90429).
• Coronary artery bypass graft (CABG) surgery. It is unclear if intravenous vitamin C helps to improve patient outcomes after CABG surgery. Details: A small clinical study shows that giving vitamin C 5 grams intravenously (IV) before anesthesia induction and 5 grams in the cardioplegia solution used during surgery shortens the length of stay in the intensive care unit (ICU) by about 8 hours (102127). However, some limited research suggests that IV vitamin C does not resolve cardiac surgery complications. A small clinical study in patients with vasoplegia after receiving CABG and other cardiac surgeries shows that receiving IV vitamin C 1.5 grams every 6 hours after being admitted to the ICU does not improve vasoplegia when compared with control (102981).
• Delirium. Oral vitamin C has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Observational research in adults with septic shock has found that receiving intravenous thiamine 400 mg daily with vitamin C 6 grams daily, both in divided doses, is not associated with reduced delirium when compared with control (103001).
• Dental plaque. It is unclear if vitamin C in a chewing gum helps to reduce dental plaque formation. Details: A small clinical study in patients with calculus shows that chewing 10 pieces of gum, each containing 60 mg of vitamin C, daily for 3 months reduces the formation of dental calculus, visible plaque, and the number of bleeding sites when compared not chewing gum (83303). The validity of this finding is limited by a lack of placebo group.
• Depression. It is unclear if oral vitamin C is beneficial for the treatment or prevention of depression. Details: A small clinical study in children and adolescents shows that taking vitamin C 500 mg orally twice daily in combination with fluoxetine 10-20 mg daily for 6 months reduces most symptoms of major depressive disorder when compared with taking fluoxetine alone (90404). However, a small clinical study in adults shows that taking vitamin C up to 1000 mg daily for 2 months does not improve the response rate or decrease symptoms of depression in adults also taking citalopram when compared with citalopram alone (96708). Reasons for these conflicting results may relate to the age of the patients, study duration, or differences in antidepressant medication being taken. One clinical guideline also provisionally recommends against the use of oral vitamin C to treat patients with depression based on low-quality evidence (110318). Some research has also evaluated vitamin C intake for the prevention of depression. A secondary analysis of pre- and peri-menopausal adults enrolled in the Study of Women's Health Across the Nation (SWAN) program suggests that vitamin C intake is inversely associated with depressive symptoms. This association persisted regardless of age, race, physical activity, body mass index, antidepressant use or menopausal status (108083). The validity of these findings is limited due to the secondary nature of this study; additionally, follow-up time is unclear.
• Diabetes. It is unclear if oral vitamin C prevents diabetes. Some low-quality research suggests that vitamin C might improve glycemic control in patients with diabetes. Details: Population research has not found a link between dietary vitamin C and the risk of developing type 2 diabetes (14004). However, low certainty clinical research has found some benefit of taking vitamin C supplements for glycemic control. Two meta-analyses of several small, heterogeneous clinical studies in patients with type 2 diabetes show that taking vitamin C 200-3000 mg daily for 2-48 weeks reduces fasting blood glucose by approximately 11 mg/dL (112478) and glycated hemoglobin (HbA1c) by an average of 0.5% when compared with placebo, standard treatment, or no treatment (105461,112478). Subgroup analyses suggest that durations of supplementation longer than 12 weeks show greater glycemic benefit, and although one meta-analysis suggests there is no dose-response relationship (105461), another meta-analysis suggests that doses of vitamin C 1000 mg and higher are most beneficial for improving glycemic indices (112478). Some research has evaluated the effects of vitamin C supplementation on the lipid profile in patients with diabetes, with mixed findings. One meta-analysis of 17 small clinical studies shows that taking vitamin C 200-3000 mg daily for 2 to 48 weeks improves levels of triglycerides and total cholesterol, but not low-density lipoprotein (LDL) or high-density lipoprotein (HDL) cholesterol. Subgroup analysis suggests that study durations of at least 12 weeks show greater benefit (106621). However, two other meta-analyses in patients with diabetes, one of 16 small heterogenous clinical studies and one of 11 small clinical studies, show no clinically important improvement in lipid levels after vitamin C supplementation (105461,105464).
• Dry mouth. Oral vitamin C has only been evaluated in combination with vitamin E; its effect when used alone is unclear. Details: A small clinical trial in patients receiving radiotherapy for head and neck cancer shows that taking vitamin E 100 IU and vitamin C 500 mg twice daily for an average of 3 months improves dry mouth when compared to baseline (99080). The validity of these results is limited by the lack of comparison with a control group.
• Endometrial cancer. Increased dietary vitamin C has been linked to reduced risk of endometrial cancer. Details: Population research has found that intake of vitamin C from dietary sources is associated with a slightly decreased risk of endometrial cancer when compared with control. However, this benefit is not observed when results from a prospective cohort study are assessed (34578).
• Endometriosis. Oral vitamin C has only been evaluated in combination with vitamin E; its effect when used alone is unclear. Details: A small clinical study in patients with endometriosis and pelvic pain shows that taking vitamin C 1000 mg and vitamin E 800 IU daily for 8 weeks improves dysmenorrhea, dyspareunia, and chronic pelvic pain scores when compared with placebo. Vitamin C and vitamin E supplementation also reduces some biochemical markers of oxidative stress when compared with placebo (106622). Additionally, a meta-analysis of 4 other, mostly small clinical studies in patients with endometriosis shows that taking vitamin C 1000 mg and vitamin E 800-1200 IU daily for 6-8 weeks reduces chronic pelvic pain and improves dysmenorrhea and dyspareunia when compared with placebo (114491).
• Endoscopy-associated adverse effects. It is unclear if a topical vitamin C spray reduces mucosal irritation in patients undergoing Lugol chromoendoscopy. Details: A small clinical trial in patients receiving a Lugol chromoendoscopy shows that spraying a vitamin C 2% solution after the application of the Lugol iodine 2% solution reduces the severity of mucosal irritation, heartburn, and pain when compared with using a normal saline spray after the Lugol iodine 2% solution (104030).
• Esophageal cancer. Oral vitamin C has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Population research has found that higher dietary intake of vitamin C is associated with reduced odds of esophageal adenocarcinoma. A 50 gram increase in dietary vitamin C intake is associated with a 13% reduced odds of esophageal cancer (34551,98770). However, a meta-analysis of clinical research shows that taking a vitamin C supplement in combination with beta-carotene and vitamin E does not reduce the risk of esophageal cancer (34581).
• Exercise-induced asthma. Small clinical studies suggest that oral vitamin C may modestly improve symptoms in patients with exercise-induced asthma. Details: A meta-analysis of the available clinical research shows that vitamin C supplementation might reduce exercise-induced breathlessness when compared with placebo or control. However, the available research is of poor quality, and no clear conclusions can be drawn regarding its benefits for exercise-induced asthma (90409).
• Exercise-induced muscle damage. It is unclear if oral vitamin C is beneficial in exercise-induced muscle damage. Details: A small clinical study in healthy females shows that taking vitamin C 1000 mg before moderate intensity cycling does not prevent muscle damage when compared with placebo (99837). Another small clinical study in endurance-trained runners shows that taking vitamin C 1000 mg and vitamin E (as alpha-tocopherol) 235 mg 2 hours prior to an exercise protocol does not reduce delayed onset muscle soreness or improve other markers of exercise-induced muscle damage when compared with placebo (109961).
• Gallbladder disease. It is unclear if oral vitamin C reduces the risk of gallbladder disease. Details: Cross-sectional epidemiological evidence has found that vitamin C supplementation and increased vitamin C serum levels are associated with a decreased risk of developing gallbladder disease in females, but not males (5877).
• Gastric cancer. It is unclear if dietary or supplemental vitamin C reduces the risk of gastric cancer. Details: Most population research has not found an association between DIETARY intake of vitamin C and gastric cancer risk (9194,10822,10819,90083). Also, clinical research shows that taking vitamin C supplements in combination with other antioxidants does not reduce the risk of gastric cancer or precancerous gastric lesions (14447,34581,90085). However, some research suggests that it might be associated with a reduced risk for specific forms of gastric cancer (9838,90083). One clinical study shows that taking vitamin C orally 500 mg daily for 6 months after eradication of Helicobacter pylori infection decreases the incidence of precancerous changes in stomach tissue when compared with no treatment (10359). Also, other clinical research shows that taking vitamin C orally 1 gram daily helps promote the regression of precancerous gastric lesions in people at high risk for gastric cancer (2579). In 2009, the US Food and Drug Administration (FDA) determined that it would allow a qualified health claim stating that vitamin C supplements may reduce the risk of gastric cancer. However, the FDA has concluded that it is highly uncertain that vitamin C supplements actually reduce the risk of gastric cancer (102332).
• Gastritis. There is limited evidence on the oral use of vitamin C in omeprazole-induced corpus gastritis. Details: A small clinical study shows that taking vitamin C orally 1200 mg daily along with omeprazole decreases corpus gastritis associated with omeprazole therapy in patients with H. pylori infection (10360).
• Gout. It is unclear if oral vitamin C helps to prevent or manage gout. Details: Population research in men has found that taking vitamin C 500-1500 mg daily from the diet and/or supplements is associated with up to a 34% reduced risk of gout when compared with less than 250 mg daily (16755). Also, men who ingest over 500 mg of vitamin C daily from the diet and supplements have serum uric acid levels that are slightly lower than men who consume less than 90 mg daily (16820). However, taking supplemental vitamin C 500 mg daily for 8 weeks does not seem to lower serum uric acid levels in patients who already have gout (90423).
• Hearing loss. There is limited evidence on the intravenous use of vitamin C in idiopathic sudden sensorineural hearing loss. It is unclear if dietary vitamin C intake can affect the risk of hearing loss. Details: A small clinical study in patients with idiopathic sudden sensorineural hearing loss shows that receiving intravenous high-dose vitamin C 200 mg/kg daily in combination with steroid therapy for 10 days, followed by oral vitamin C 2000 mg daily for 30 days, increases recovery rate two-fold and modestly improves hearing threshold levels when compared with receiving steroid therapy only (90417). In addition, population research in females has found that high dietary intake of vitamin C is associated with a 22% increased risk of developing self-reported hearing loss over a 22-year period when compared with low intake (109807).
• Heart transplant complications. Oral vitamin C has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical trial shows that a combination of vitamin C 500 mg and vitamin E 400 IU, taken twice daily for 1 year starting within the first 2 years after cardiac transplant, reduced the progression of vasculopathy as measured by intravascular ultrasonography (IVUS) when compared with placebo. This suggests that the combination may help slow the progression of CAV (82826).
• Hepatitis C. It is unclear if oral vitamin C is beneficial in patients with hepatitis C. Details: A small clinical study in patients with confirmed hepatitis C shows that taking vitamin C 1000 mg daily with conventional therapy (sofosbuvir plus daclatasvir) for 4 weeks improves serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), bilirubin, and albumin when compared with conventional therapy alone (109463).
• HIV/AIDS. Oral vitamin C has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small, low-quality study in men with HIV shows that taking vitamin C 250 mg daily in combination with vitamin A, beta-carotene, vitamin E, selenium, and coenzyme Q10 does not improve viral load, although it seems to improve markers of oxidative stress when compared to baseline. However, a 1000 mg dose of vitamin C, as well as higher doses of the other antioxidants, do not seem to provide any additional effect (9830).
• HIV transmission. Oral vitamin C has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A clinical study in HIV-positive mothers shows that taking vitamin B, vitamin C, and vitamin E daily during pregnancy and while breast-feeding for 20 weeks seems to reduce child mortality and HIV transmission through breast milk when compared with taking vitamin A (9801).
• Hyperphosphatemia. Intravenous vitamin C might be beneficial for reducing phosphate levels in patients with end-stage renal disease. Details: A small clinical study in hemodialysis patients with elevated phosphorus levels suggests that administering vitamin C 500 mg intravenously three times weekly for 8 weeks reduces phosphorus levels about seven-fold when compared with placebo (90414).
• Idiopathic interstitial pneumonia. Oral vitamin C has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in patients with idiopathic pulmonary fibrosis, a form of idiopathic interstitial pneumonia, shows that taking a combination of vitamin C 250 mg every other day, vitamin D 50,000 IU daily, and vitamin E 200 IU daily for 12 weeks improves some, but not all, measures of lung function and reduces markers of inflammation and oxidative stress when compared to baseline (109464). The validity of these findings is limited by a lack of placebo control group.
• Infertility. It is unclear if oral vitamin C is beneficial in anovulatory females. Details: A very small clinical study suggests that taking vitamin C 400-1000 mg daily might improve fertility, resulting in ovulation and pregnancy in some anovulatory females, when compared to baseline (14018). The validity of these findings is limited by the small study size and lack of a comparator group. However, a very large observational study suggests that there is no association between dietary vitamin C intake and in-vitro fertilization (IVF) outcomes including good oocyte quality, embryo transfer success rates, clinical pregnancy rates, and successful term pregnancy rates in subfertile couples who are candidates for IVF (112097).
• Male infertility. It is unclear if oral or intravenous vitamin C is beneficial in males with infertility. Details: A meta-analysis of three small, low-quality clinical trials in males with infertility shows that taking vitamin C up to 1000 mg daily for up to 12 weeks can improve sperm count, motility, and vitality, but does not seem to increase semen volume or sperm concentration, when compared with control (109461). It is unclear if vitamin C can increase pregnancy rates, as these studies did not assess this outcome. A retrospective study in males with or without varicocele-related infertility has found that taking a specific combination product containing vitamin C 90 mg, zinc 10 mg, L-carnitine fumarate 1725 mg, acetyl-L-carnitine 500 mg, coenzyme Q10 20 mg, folic acid 0.2 mg, selenium 0.05 mg, and vitamin B12 0.015 mg (Proxeed Plus, Sigma-Tau) orally twice daily for 6 months improves sperm count, sperm concentration, and sperm motility when compared with baseline. Improvement in semen parameters were greatest in subjects with more severe varicoceles. The validity of this study is limited by the lack of a comparator group (111296).
• Mastalgia. Oral vitamin C has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical trial in patients with mastalgia shows that taking a combination of vitamin C 100 mg, vitamin B12, and gamma-linolenic acid daily for 12 weeks does not improve the proportion of patients with minimal or no pain when compared with placebo (111059).
• Melasma. It is unclear if topical vitamin C is beneficial in patients with melasma. Details: A small clinical study in patients with bilateral symmetrically distributed facial melasma shows that applying 0.5 mL of vitamin C (Cosmotech, Alpha Medical Cosmotech) following dermapen microneedling every 2 weeks for 6 weeks is similarly effective to tranexamic acid for improving melasma severity and pigmented, but not vascular, findings on dermoscopic examination (106939). Additionally, a small clinical study in adults with melasma shows that applying 1 to 2 mL of 20% vitamin C solution following dermapen microneedling every 2 weeks for 8 weeks does not improve the degree of pigmentation when compared with topical metformin but does improve the degree of pigmentation when compared to baseline (115610).
• Nonalcoholic fatty liver disease (NAFLD). It is unclear if oral vitamin C is beneficial in patients with NAFLD. Details: A clinical study in patients with NAFLD shows that taking vitamin C 250 mg, 1000 mg, or 2000 mg daily for 12 weeks improves some biochemical markers of liver health and glucose metabolism when compared with baseline. However, the improvement from baseline was similar between groups (106942).
• Nonalcoholic steatohepatitis (NASH). Oral vitamin C has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research suggests vitamin C in combination with vitamin E might improve hepatic fibrosis in patients with NASH. However, it does not seem to decrease liver inflammation (14005).
• Non-Hodgkin lymphoma. It is unclear if oral vitamin C reduces the risk of developing diffuse large B-cell lymphoma. Details: In one population study, higher dietary or supplemental intake of vitamin C was associated with a reduced risk of diffuse large B-cell lymphoma, a type of non-Hodgkin lymphoma, when compared with lower intake in postmenopausal adults (90945).
• Oral cancer. It is unclear if oral vitamin C reduces the risk of developing oral cancer. Details: Population research has found that higher dietary intake of vitamin C is associated with a reduced risk of oral cancer (10821). However, clinical research has not shown benefit with oral vitamin C supplements. A small clinical trial in Japanese adults with oral leukoplakia shows that taking vitamin C 500 mg and beta-carotene 10 mg daily for 12 months does not reduce the development of oral cancer over 5 years when compared with vitamin C 50 mg daily (91384).
• Oral leukoplakia. Oral vitamin C has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical trial in Japanese adults with oral leukoplakia shows that taking vitamin C 500 mg and beta-carotene 10 mg daily for 12 months does not improve leukoplakia symptoms or reduce the development of oral cancer over 5 years when compared with vitamin C 50 mg daily (91384).
• Osteoarthritis. It is unclear if dietary vitamin C reduces the risk of developing osteoarthritis. Details: Observational research has found that increased vitamin C from dietary sources is associated with a reduced risk of cartilage loss and disease progression in people with osteoarthritis (5881).
• Osteoporosis. It is unclear if dietary vitamin C improves bone density or reduces fracture risk in patients at risk for osteoporosis. Details: Some cross-sectional observational research in postmenopausal patients without a history of smoking or estrogen use has found that higher serum vitamin C levels are associated with lower bone mineral density (9828). However, other observational research in a larger population of adults at risk for osteoporosis has found that higher dietary vitamin C intake is not associated with fracture risk (104415).
• Ovarian cancer. Dietary vitamin C might not affect the risk of ovarian cancer. Details: Epidemiological research has found that dietary vitamin C intake is not linked with ovarian cancer risk (9193,102977).
• Pancreatitis. It is unclear if intravenous vitamin C is beneficial in patients with acute pancreatitis. Details: A small meta-analysis of clinical studies in patients with acute pancreatitis shows that intravenous vitamin C does not improve the odds of developing organ failure when compared with placebo or no intervention. Intravenous vitamin C seems to reduce hospital stay, but not in-hospital mortality (106941).
• Parkinson disease. Dietary vitamin C might not affect the risk of developing this condition. Details: Observational research has found that moderate or high dietary intake of vitamin C is not associated with a reduced risk of Parkinson disease (83316).
• Periodontitis. Oral vitamin C has only been evaluated in combination with other ingredients; its effect when used alone is unclear. It is also unclear if dietary vitamin C reduces the risk of periodontitis. Details: A small clinical study in patients with moderate or advanced periodontitis shows that taking a supplement containing vitamin C 100 mg, alpha-lipoic acid, coenzyme Q10, cranberry extract, grapeseed extract, selenium, vitamin E, and zinc twice daily for 8 weeks in addition to standard nonsurgical therapy does not improve periodontal indices including bleeding on probing, gingival recession, plaque index, or inflammation, among others, when compared with placebo (111708). It is unclear if these effects are due to vitamin C, other ingredients, or the combination. There is also interest in whether dietary vitamin C intake impacts the risk of periodontitis. Observational research in US adults has found that individuals with dietary intake of vitamin C in the third quartile, but not the second or fourth quartiles, have lower odds of periodontitis when compared with vitamin C intake in the lowest quartile. Furthermore, the investigators identified a non-linear relationship between vitamin C intake and periodontitis risk, suggesting that individuals with intakes either much lower or much higher than 158 mg daily are at increased risk of developing periodontitis (109958).
• Peripheral arterial disease (PAD). It is unclear if dietary vitamin C helps to reduce the risk of developing PAD. Details: In females, epidemiological evidence has found that dietary intake of vitamin C of 142 mg daily or greater is associated with a 36% reduced risk of PAD when compared with lower intake levels of less than 80 mg daily (10130).
• Physical performance. It is unclear if oral vitamin C helps to improve physical performance and muscle strength in older people. Details: Population research has found that higher intake of dietary vitamin C is associated with improved physical performance and muscle strength in elderly people (14006). In contrast, a small clinical study in elderly men undergoing strength training shows that taking vitamin C 1000 mg and vitamin E 258IU daily for 12 weeks does not increase strength, and might even attenuate increases in muscle mass, when compared with strength training alone (96701).
• Pneumonia. It is unclear if oral or intravenous vitamin C helps to prevent or treat pneumonia. Details: A meta-analysis of 6 clinical studies in adults with community-acquired pneumonia shows that oral or intravenous vitamin C does not reduce overall mortality, hospital or intensive care unit length of stay, or the risk of mechanical ventilation when compared with control (114490). The interpretation of these results is limited by significant heterogeneity of the included studies. An earlier meta-analysis of two small, low-quality clinical studies in children shows that vitamin C does not seem to reduce the risk of pneumonia when compared with a control (104033).
• Postoperative recovery. It is unclear if oral or intravenous vitamin C improves postoperative recovery. Details: Meta-analyses of clinical research show that oral or intravenous vitamin C can shorten the duration of hospitalization after cardiac surgery when compared with control (91233,96703). However, other research shows no decrease in intensive care unit (ICU) or hospital stay with vitamin C supplementation (96705), while another clinical study in patients undergoing cardiac surgery with extracorporeal circulation shows that intravenous vitamin C administered during surgery and 48 hours after surgery reduces ICU stay and re-admission rates, wound infection, and hospital mortality, but not length of hospital stay, when compared with control (114492). A meta-analysis of 37 clinical trials in adults undergoing low- to high-risk noncardiac surgery (i.e., orthopedic, abdominal, gynecologic, or kidney transplantation), shows that receiving perioperative vitamin C, either orally or intravenously, does not improve duration of hospitalization or overall mortality when compared with control (108087).
• Postoperative pulmonary complications. It is unclear if intravenous vitamin C improves postoperative pulmonary complications. Details: A large, single-blind clinical study in patients with recent cardiac surgery with extracorporeal circulation shows that parenteral administration of vitamin C 50 mg/kg intraoperatively and 50 mg/kg every 6 hours for the next 48 hours, followed by oral vitamin C 2000 mg daily until 1-week post-discharge, reduces the incidence of postoperative pulmonary complications (PPC) by 22% and improves PPC severity scores when compared with control. Specifically, vitamin C reduces the incidence of pneumothorax, pleural effusion, pneumonia, and re-intubation and may ameliorate lung damage as suggested by higher Horowitz index when compared with control (114492). A small clinical trial in patients undergoing low-risk cardiac surgery shows that receiving intravenous vitamin C 1 gram 10 minutes after anesthesia might slightly reduce the rate of postoperative pulmonary complications when compared with receiving a saline injection (104034).
• Postoperative swelling. It is unclear if vitamin C reduces postoperative swelling after dental surgery. Details: A small observational study in adults undergoing surgery for wisdom tooth extraction shows that taking vitamin C 500 mg three times daily for 7 days in addition to standard treatment reduces swelling 7 days after surgery when compared with control. However, vitamin C does not seem to reduce swelling 3 days after surgery when compared with control, suggesting that longer durations are needed for anti-inflammatory effects (113664).
• Premature rupture of membranes (PROM). Oral vitamin C seems to reduce the risk of PROM in some patients; however, the addition of oral vitamin E seems to negate any benefit. Details: A meta-analysis of clinical research shows that taking vitamin C alone decreases the risk of both term and preterm PROM by 45% and 34%, respectively, when compared with placebo or control (96707). Another meta-analysis of clinical research shows that taking vitamin C during pregnancy decreases the risk of PROM by 43% and preterm PROM by 33%, but does not decrease the risk of term PROM, when compared with a control. While vitamin C was studied in doses of 100, 500, and 1000 mg daily, the decreased risk of PROM was only observed in studies of 100 mg daily (114493). A moderate-sized clinical study in patients with a history of PROM shows that taking vitamin C 100 mg daily, starting at 14 weeks' gestation, increases the gestational age at recurrent PROM by around 1 week and increases the gestational age at birth by around 1.3 weeks when compared with placebo (109960). Additionally, a meta-analysis of observational studies suggests that vitamin C levels in the blood tend to be lower in patients with PROM, particularly preterm PROM (114493). Taking vitamin C in combination with vitamin E, however, does not seem to reduce the risk of term or preterm PROM; some research suggests that it might even increase the risk of non-preterm PROM (83472,96707). However, other research shows that taking vitamin C 1000 mg plus vitamin E 400 IU daily, beginning at 24 to 34 weeks gestation and continuing until delivery, may help increase the latency period until delivery by 5 days and increase gestational age at delivery by almost 1 week when compared with placebo in patients with preterm PROM (90078).
• Pressure ulcers. It is unclear if oral vitamin C, when used alone or in combination with other ingredients, can improve the healing of pressure ulcers. Details: A small clinical study in institutionalized patients with pressure ulcers shows that taking vitamin C 500 mg twice daily for 12 weeks does not improve wound closure or increase healing rates when compared with vitamin C 10 mg twice daily (83617). Oral vitamin C has also been evaluated in combination with other ingredients for the treatment of grade II-IV pressure ulcers. Two small clinical studies in hospitalized patients with pressure ulcers shows that administering an oral nutritional supplement enriched with vitamin C, L-arginine, and zinc improves ulcer healing when compared with a standard diet (31953,87173). Also, clinical research in patients living in long-term care facilities shows that taking an oral nutritional supplement enriched in protein, vitamin C, L-arginine, and zinc daily for 9 weeks reduces ulcer area and decreases oozing when compared to baseline (32045). The validity of this finding is limited by the lack of a comparator group.
• Radiation proctopathy. Oral vitamin C has only been evaluated in combination with vitamin E; its effect when used alone is unclear. Details: A small clinical study in patients with chronic radiation proctitis shows that vitamin C 500 mg plus vitamin E 400 IU three times daily might improve symptoms when compared with baseline (9825). The validity of these findings is limited by the lack of a comparator group.
• Renal cell carcinoma. It is unclear if increased dietary intake of vitamin C helps to reduce the risk of renal cell carcinoma. Details: Population research has found that increased dietary intake of vitamin C is associated with a 12% reduced risk of renal cell carcinoma (98779).
• Respiratory tract infections. It is unclear if oral vitamin C is beneficial for preventing respiratory tract infections or reducing the duration of these infections. Details: A meta-analysis of clinical research in children and adults shows that, when compared with placebo, oral vitamin C supplementation reduces the average number of symptomatic days per individual, but does not reduce the average symptom days per respiratory episode. Also, vitamin C intake does not reduce the incidence or severity of respiratory disease or improve recovery in hospitalized patients with respiratory tract infections (108077). The validity of this trial is limited by the high heterogeneity of included studies, which evaluated various vitamin C regimens, ranging from 100 mg to 8 grams daily, as preventive therapy or as an adjuvant to active treatment. A clinical study in children aged 3-10 years shows that taking vitamin C 50 mg in combination with a specific product (Lab4) containing Lactobacillus acidophilus, Bifidobacterium bifidum, and Bifidobacterium animalis subsp. lactis daily for 6 months reduces the incidence of cough and sore throat by 16% and 20%, respectively, when compared with placebo. However, it did not improve total symptoms, nasal congestion, nasal discharge, or sneezing. Also, aside from a 33% reduction in the average number of days with a sore throat, daily supplementation does not reduce the duration of individual symptoms or total symptoms (106943). It is unclear if these effects are due to vitamin C, the probiotics, or the combination.
• Restless legs syndrome (RLS). It is unclear if oral vitamin C helps to reduce symptoms of stress. Details: A small clinical study in hemodialysis patients with RLS shows that taking vitamin C 200 mg daily, alone or in combination with vitamin E 400 mg, for 8 weeks reduces the severity of RLS when compared with placebo (90093). More research is needed to determine if vitamin C is beneficial in treating RLS that is not associated with hemodialysis.
• Sunburn. Topical and oral vitamin C has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Taking vitamin C orally in combination with vitamin E seems to prevent ultraviolet (UV) radiation-induced erythema (sunburn) (4715,4716). Vitamin C in combination with high dose oral RRR-alpha-tocopherol (natural vitamin E) seems to protect against skin inflammation after exposure to UV radiation (4715). Also, applying topical vitamin C in combination with topical vitamin E and melatonin seems to provide modest photoprotective effects when used prior to UV exposure. However, it has no effect when used during or after UV exposure (4713,4714).
• Stress. It is unclear if oral vitamin C helps to reduce symptoms of stress. Details: A small clinical study in healthy adults shows that taking vitamin C 3000 mg daily for 14 days modestly reduces blood pressure and subjective stress response to psychological stress when compared with placebo (10353).
• Stroke. Observational research has found that although taking vitamin C supplements does not seem to be beneficial, eating more vitamin C-rich food is linked with reduced risk of stroke. Details: Lower plasma levels of vitamin C have been associated with increased stroke risk (90408). Additionally, population research has found that higher dietary intake of vitamin C is associated with a 8% to 19% reduction in stroke risk when compared to lower intake (90408,109779). This reduction appears to be dose-dependent, with each 100 mg/day increase in dietary vitamin C intake associated with about a 17% reduction (90408). However, taking vitamin C supplements has not been found to be associated with reduced stroke risk (1449,90408).
• Tetanus. It is unclear if intravenous vitamin C helps to reduce symptoms of tetanus. Details: A low quality clinical trial in children and young adults with tetanus shows that intravenous vitamin C 1 gram daily along with conventional treatment reduces fatality when compared to control (21539).
• Tooth extraction. It is unclear if oral vitamin C is beneficial for reducing pain or improving healing after tooth extraction. Details: A small clinical study in healthy patients aged 14-41 years who are undergoing bilateral premolar extraction shows that taking vitamin C 200 mg three times daily, beginning immediately after extraction and continued for 10 days, improves pain on days 1-3, and may reduce mesio-distal wound size between days 1 and 7, when compared with placebo, but not when compared with vitamin C 500 mg three times daily. A dose of 500 mg three times daily did not improve pain scores or extraction wound healing when compared with placebo (108084). The validity of this trial is limited by the short duration of treatment; additionally, this study did not report baseline vitamin C levels.
• Urinary tract infections (UTIs). Although there is interest in using oral vitamin C for UTIs, there is insufficient reliable information about the clinical effects of vitamin C for this condition.
• Vascular dementia. It is unclear if oral vitamin C reduces the risk of vascular dementia. Details: Population research has found that supplemental intake of vitamin C and vitamin E is associated with a reduced risk of vascular dementia in Japanese-American men (4636). However, when cases in which dementia was diagnosed prior to the study are excluded from data analysis, intake of vitamin C and vitamin E is not associated with a reduced risk of vascular dementia in these patients (9824).
• Wound healing. It is unclear if oral vitamin C improves the healing of chronic foot ulcers. It is also unclear if intravenous vitamin C improves healing of surgical wounds after total abdominal hysterectomy. Details: A very small clinical study in adults with chronic foot ulcers shows that taking slow-release vitamin C 500 mg daily for 8 weeks seems to result in a median of 100% ulcer healing, compared with a median of 14% ulcer healing in patients taking glucosamine 1000 mg daily (105456). This finding is limited due to the small and heterogeneous patient population, which included patients with diabetes, vascular disease, and/or vitamin C deficiency. Another small clinical study in patients undergoing total abdominal hysterectomy shows that administration of intravenous vitamin C 1 gram the night before surgery and 1 gram during surgery does not reduce the rate of surgical site infection or wound dehiscence when compared with placebo (109465). However, this study may not have been adequately powered to detect differences between groups. More evidence is needed to rate vitamin C for these uses.

(Read more about VITAMIN C)

POSSIBLY SAFE ...when used orally and appropriately, short-term. Ashwagandha has been used with apparent safety in doses of up to 1250 mg daily for up to 6 months (3710,11301,19271,90649,90652,90653,97292,101816,102682,102683) (102684,102685,102687,103476,105824,109586,109588,109589,109590). ...when used topically. Ashwagandha lotion has been used with apparent safety in concentrations up to 8% for up to 2 months (111538).

PREGNANCY: LIKELY UNSAFE
when used orally. Ashwagandha has abortifacient effects (12).

LACTATION:
Insufficient reliable information available; avoid using.

(Read more about ASHWAGANDHA)

POSSIBLY SAFE ...when banaba extract is used orally and appropriately, short-term (11954,92848,92849). A specific banaba extract (Glucosol) has been safely used at doses of 32-48 mg daily for 2 weeks (11954). Another specific product containing extracts of banaba leaf and Padang cassia (Inlacin, Dexa Medica) has been safely used at doses up to 100 mg daily for 12 weeks (92848,92849). There is insufficient reliable information available about the safety of banaba extract when used long-term.

PREGNANCY AND LACTATION:
Insufficient reliable information available; avoid using.

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LIKELY SAFE ...when used orally or intravenously and appropriately. Calcium is safe when used in appropriate doses (7555,12928,12946,95817). However, excessive doses should be avoided. The Institute of Medicine sets the daily tolerable upper intake level (UL) for calcium according to age as follows: Age 0-6 months, 1000 mg; 6-12 months, 1500 mg; 1-8 years, 2500 mg; 9-18 years, 3000 mg; 19-50 years, 2500 mg; 51+ years, 2000 mg (17506). Doses over these levels can increase the risk of side effects such as kidney stone, hypercalciuria, hypercalcemia, and milk-alkali syndrome. There has also been concern that calcium intake may be associated with an increased risk of cardiovascular disease (CVD) and coronary heart disease (CHD), including myocardial infarction (MI). Some clinical research suggests that calcium intake, often in amounts over the recommended daily intake level of 1000-1300 mg daily for adults, is associated with an increased risk of CVD, CHD, and MI (16118,17482,91350,107233). However, these studies, particularly meta-analyses, have been criticized for excluding trials in which calcium was administered with vitamin D (94137). Other clinical studies suggest that, when combined with vitamin D supplementation, calcium supplementation is not associated with an increased risk of CVD, CHD, or MI (93533,107231). Other analyses report conflicting results and have not shown that calcium intake affects the risk of CVD, CHD, or MI (92994,93533,97308,107231). Advise patients not to consume more than the recommended daily intake of 1000-1200 mg per day, to consider total calcium intake from both dietary and supplemental sources (17484), and to combine calcium supplementation with vitamin D supplementation (93533).

POSSIBLY UNSAFE ...when used orally in excessive doses. The National Academy of Medicine sets the daily tolerable upper intake level (UL) for calcium according to age as follows: 19-50 years, 2500 mg; 51 years and older, 2000 mg (17506). Doses over these levels can increase the risk of side effects such as kidney stones, hypercalciuria, hypercalcemia, and milk-alkali syndrome. There has also been concern that calcium intake may be associated with an increased risk of cardiovascular disease (CVD) and coronary heart disease (CHD), including myocardial infarction (MI). Some clinical research suggests that calcium intake, often in amounts over the recommended daily intake level of 1000-1300 mg daily for adults, is associated with an increased risk of CVD, CHD, and MI (16118,17482,91350,107233). However, these studies, particularly meta-analyses, have been criticized for excluding trials in which calcium was administered with vitamin D (94137). Other clinical studies suggest that, when combined with vitamin D supplementation, calcium supplementation is not associated with an increased risk of CVD, CHD, or MI (93533,107231). Other analyses report conflicting results and have not shown that calcium intake affects the risk of CVD, CHD, or MI (92994,93533,97308,107231). Advise patients to not consume more than the recommended daily intake of 1000-1200 mg per day, to consider total calcium intake from both dietary and supplemental sources (17484), and to combine calcium supplementation with vitamin D supplementation (93533).

CHILDREN: LIKELY SAFE
when used orally and appropriately. Calcium is safe when used in appropriate doses (17506).

CHILDREN: POSSIBLY UNSAFE
when used orally in excessive doses. The Institute of Medicine sets the daily tolerable upper intake level (UL) for calcium according to age as follows: 0-6 months, 1000 mg; 6-12 months, 1500 mg; 1-8 years, 2500 mg; 9-18 years, 3000 mg (17506). Doses over these levels can increase the risk of side effects such as kidney stones, hypercalciuria, hypercalcemia, and milk-alkali syndrome.

PREGNANCY AND LACTATION: LIKELY SAFE
when used orally and appropriately (945,1586,3263,3264,17506). The World Health Organization (WHO) recommends prescribing oral calcium supplementation 1.5-2 grams daily during pregnancy to those with low dietary calcium intake to prevent pre-eclampsia (97347).

PREGNANCY AND LACTATION: POSSIBLY UNSAFE
when used orally in excessive doses. The Institute of Medicine sets the same daily tolerable upper intake level (UL) for calcium according to age independent of pregnancy status: 9-18 years, 3000 mg; 19-50 years, 2500 mg (17506). Doses over these amounts might increase the risk of neonatal hypocalcemia-induced seizures possibly caused by transient neonatal hypoparathyroidism in the setting of excessive calcium supplementation during pregnancy, especially during the third trimester. Neonatal hypocalcemia is a risk factor for neonatal seizures (97345).

(Read more about CALCIUM)

LIKELY SAFE ...when used orally and appropriately in medicinal amounts, short-term. Chromium has been safely used in doses up to 1000 mcg daily for up to 6 months (1934,5039,5040,6858,6859,6860,6861,6862,6867,6868)(7135,7137,10309,13053,14325,14440,17224,90057,90061)(90063,94234,95095,95096,95097,98687); however, most of these studies have used chromium doses in a range of 150-600 mcg. The Food and Drug Administration (FDA) and Institute of Medicine (IOM) evaluations of the safety of chromium suggest that it is safe when used in doses of 200 mcg daily for up to 6 months (13241,13242).

POSSIBLY SAFE ...when used orally and appropriately in medicinal amounts, long-term. Chromium has been safely used in a small number of studies at doses of 200-1000 mcg daily for up to 2 years (7060,7135,42618,42628,42666,110605,110607,110609). However, the Food and Drug Administration (FDA) and Institute of Medicine (IOM) evaluations of the safety of chromium suggest that it is safe when used in doses of 200 mcg daily for up to 6 months (13241,13242).

CHILDREN: LIKELY SAFE
when used orally and appropriately in amounts not exceeding the daily adequate intake (AI) levels by age: 0-6 months, 0. 2 mcg; 7-12 months, 5.5 mcg; 1-3 years, 11 mcg; 4-8 years, 15 mcg; males 9-13 years, 25 mcg; males 14-18 years, 35 mcg; females 9-13 years, 21 mcg; females 14-18 years, 24 mcg (7135). POSSIBLY SAFE...when used orally and appropriately in amounts exceeding AI levels. Chromium 400 mcg daily has been used safely for up to 6 weeks (42680).

PREGNANCY: LIKELY SAFE
when used orally and appropriately in amounts not exceeding adequate intake (AI) levels. The AI for pregnancy is 28 mcg daily for those 14-18 years of age and 30 mcg daily for those 19-50 years of age (7135).

PREGNANCY: POSSIBLY SAFE
when used orally in amounts exceeding the adequate intake (AI) levels. There is some evidence that patients with gestational diabetes can safely use chromium in doses of 4-8 mcg/kg (1953); however, patients should not take chromium supplements during pregnancy without medical supervision.

LACTATION: LIKELY SAFE
when used orally and appropriately in amounts not exceeding adequate intake (AI) levels. The AI for lactation is 44 mcg daily for those 14-18 years of age and 45 mcg daily for those 19-50 years of age (7135). Chromium supplements do not seem to increase normal chromium concentration in human breast milk (1937). There is insufficient reliable information available about the safety of chromium when used in higher amounts while breast-feeding.

(Read more about CHROMIUM)

LIKELY SAFE ...when green tea is consumed as a beverage in moderate amounts (733,6031,9222,9223,9225,9226,9227,9228,14136,90156)(90159,90168,90174,90184,95696). Green tea contains caffeine. According to a review by Health Canada, and a subsequent large meta-analysis conducted in the US, drinking up to 8 cups of green tea daily, or approximately 400 mg of caffeine, is not associated with significant adverse cardiovascular, bone, behavioral, or reproductive effects in healthy adults (11733,98806). The US Dietary Guidelines Advisory Committee states that there is strong and consistent evidence that consumption of caffeine 400 mg daily is not associated with increased risk of major chronic diseases, such as cardiovascular disease or cancer, in healthy adults (98806). ...when green tea extract cream or ointment is used topically and appropriately, short-term. A green tea extract 3% cream, applied twice daily, has been used with apparent safety for up to 8 weeks, and a specific green tea extract ointment (Veregen, Bradley Pharmaceuticals) providing 15% kunecatechins has been safely used for up to 16 weeks (15067). The safety of treatment for longer durations or multiple treatment courses is not known.

POSSIBLY SAFE ...when green tea extract is used orally. Green tea extract containing 7% to 12% caffeine has been used safely for up to 2 years (8117,37725). Also decaffeinated green tea extract up to 1.3 grams daily enriched in EGCG has been used safely for up to 12 months (90158,97131). In addition, green tea extract has been safely used as part of an herbal mixture also containing garcinia, coffee, and banaba extracts for 12 weeks (90137). ...when used topically and appropriately as a cream or mouthwash (6065,11310,90141,90150,90151).

POSSIBLY UNSAFE ...when consumed as a beverage in large quantities. Green tea contains a significant amount of caffeine. Chronic use, especially in large amounts, can produce tolerance, habituation, psychological dependence, and other significant adverse effects. Doses of caffeine greater than 600 mg per day, or approximately 12 cups of green tea, have been associated with significant adverse effects such as tachyarrhythmias and sleep disturbances (11832). These effects would not be expected to occur with the consumption of decaffeinated green tea. Keep in mind that only the amount of ADDED caffeine must be stated on product labels. The amount of caffeine found in ingredients such as green tea, which naturally contains caffeine, does not need to be provided. This can make it difficult to determine the total amount of caffeine in a given product. There is also some speculation that green tea products containing higher amounts of the catechin epigallocatechin gallate (EGCG) might have increased risk of adverse events. Some research has found that taking green tea products containing EGCG levels greater than 200 mg is associated with increased risk of mild adverse effects such as constipation, increased blood pressure, and rash (90161). Other research has found that doses of EGCG equal to or above 800 mg daily may be associated with increased risk of liver injury in humans (95440,95696,97131).

LIKELY UNSAFE ...when used orally in very high doses. The fatal acute oral dose of caffeine is estimated to be 10-14 grams (150-200 mg per kilogram). Serious toxicity can occur at lower doses depending on variables in caffeine sensitivity such as smoking, age, and prior caffeine use (11832).

CHILDREN: POSSIBLY SAFE
when used orally by children and adolescents in amounts commonly found in foods and beverages (4912,11833). Intake of caffeine in doses of less than 2.5 mg/kg daily is not associated with significant adverse effects in children and adolescents (11733,98806). ...when used for gargling three times daily for up to 90 days (90150). There is insufficient reliable information available about the safety of green tea extract when used orally in children. However, taking green tea extract orally has been associated with potentially serious, albeit uncommon and unpredictable cases, of hepatotoxicity in adults. Therefore, some experts recommend that children under the age of 18 years of age do not use products containing green tea extract (94897).

PREGNANCY: POSSIBLY SAFE
when used orally in moderate amounts. Due to the caffeine content of green tea, pregnant patients should closely monitor their intake to ensure moderate consumption. Fetal blood concentrations of caffeine approximate maternal concentrations (4260). The use of caffeine during pregnancy is controversial; however, moderate consumption has not been associated with clinically important adverse fetal effects (2708,2709,2710,2711,9606,11733,16014,16015,98806). In some studies consuming amounts over 200 mg daily is associated with a significantly increased risk of miscarriage (16014). This increased risk may be most likely to occur in those with genotypes that confer a slow rate of caffeine metabolism (98806). According to a review by Health Canada, and a subsequent large meta-analysis conducted in the US, most healthy pregnant patients can safely consume doses up to 300 mg daily without an increased risk of spontaneous abortion, stillbirth, preterm birth, fetal growth retardation, or congenital malformations (11733,98806). Advise keeping caffeine consumption below 300 mg daily. This is similar to the amount of caffeine in about 6 cups of green tea. Keep in mind that only the amount of ADDED caffeine must be stated on product labels. The amount of caffeine found in ingredients such as green tea, which naturally contains caffeine, does not need to be provided. This can make it difficult to determine the total amount of caffeine in a given product. Based on animal models, green tea extract catechins are also transferred to the fetus, but in amounts 50-100 times less than maternal concentrations (15010). The potential impact of these catechins on the human fetus is not known, but animal models suggest that the catechins are not teratogenic (15011).

PREGNANCY: POSSIBLY UNSAFE
when used orally in amounts providing more than 300 mg caffeine daily. Caffeine from green tea crosses the placenta, producing fetal blood concentrations similar to maternal levels (4260). Consumption of caffeine in amounts over 300 mg daily is associated with a significantly increased risk of miscarriage in some studies (16014,98806). Advise keeping caffeine consumption from all sources below 300 mg daily. This is similar to the amount of caffeine in about 6 cups of green tea. High maternal doses of caffeine throughout pregnancy have also resulted in symptoms of caffeine withdrawal in newborn infants (9891). High doses of caffeine have also been associated with spontaneous abortion, premature delivery, and low birth weight (2709,2711). However, some research has also found that intrauterine exposure to even modest amounts of caffeine, based on maternal blood levels during the first trimester, is associated with a shorter stature in children ages 4-8 years (109846). Keep in mind that only the amount of ADDED caffeine must be stated on product labels. The amount of caffeine found in ingredients such as green tea, which naturally contains caffeine, does not need to be provided. This can make it difficult to determine the total amount of caffeine in a given product. There is also concern that consuming large amounts of green tea might have antifolate activity and potentially increase the risk of folic acid deficiency-related birth defects. Catechins in green tea inhibit the enzyme dihydrofolate reductase in vitro (15012). This enzyme is responsible for converting folic acid to its active form. Preliminary evidence suggests that increasing maternal green tea consumption is associated with increased risk of spina bifida (15068). Also, evidence from epidemiological research suggests that serum folate levels in pregnant patients with high green tea intake (57.3 mL per 1000 kcal) are decreased compared to participants who consume moderate or low amounts of green tea (90171). More evidence is needed to determine the safety of using green tea during pregnancy. For now, advise pregnant patients to avoid consuming large quantities of green tea.

LACTATION: POSSIBLY SAFE
when used orally in moderate amounts. Due to the caffeine content of green tea, nursing parents should closely monitor caffeine intake. Breast milk concentrations of caffeine are thought to be approximately 50% of maternal serum concentrations (9892).

LACTATION: POSSIBLY UNSAFE
when used orally in large amounts. Consumption of green tea might cause irritability and increased bowel activity in nursing infants (6026). There is insufficient reliable information available about the safety of green tea extracts when applied topically during breast-feeding.

(Read more about GREEN TEA)

POSSIBLY SAFE ...when used orally, short-term. Holy basil leaf extract has been used with apparent safety at a dose of 500 mg daily for 60-90 days (12242,18107,19575,91571,96944). ...when used topically in the mouth, short-term. Holy basil has been used with apparent safety as a 4% mouthwash solution for up to 30 days (91570,103621).

PREGNANCY AND LACTATION: POSSIBLY UNSAFE
when used in high doses during pregnancy or when trying to conceive. Animal research suggests that relatively high doses of holy basil extract (200 mg/kg) may reduce implantation rate when used for one week, while long-term use of higher doses (2-4 grams/kg) may decrease the number of full-term pregnancies (55040,91569). There is insufficient reliable information available regarding the safety of holy basil during lactation; avoid using.

(Read more about HOLY BASIL)

LIKELY SAFE ...when used orally in amounts commonly found in foods. Lecithin has Generally Recognized As Safe (GRAS) status in the US (2619,105544). ...when used orally and appropriately in medicinal amounts. Lecithin has been used safely in doses of up to 30 grams daily for up to 6 weeks (5140,5149,5152,5156,14817,14822,14838,19212). ...when used topically (4914).

PREGNANCY AND LACTATION: LIKELY SAFE
when used orally in food amounts. Lecithin has Generally Recognized As Safe (GRAS) status in the US (105544). There is insufficient reliable information available about the safety of medicinal amounts of lecithin during pregnancy or lactation; avoid using.

(Read more about LECITHIN)

LIKELY SAFE ...when used orally and appropriately. Oral magnesium is safe when used in doses below the tolerable upper intake level (UL) of 350 mg daily (7555). ...when used parenterally and appropriately. Parenteral magnesium sulfate is an FDA-approved prescription product (96484).

POSSIBLY UNSAFE ...when used orally in excessive doses. Doses greater than the tolerable upper intake level (UL) of 350 mg daily frequently cause loose stools and diarrhea (7555).

CHILDREN: LIKELY SAFE
when used orally and appropriately. Magnesium is safe when used in doses below the tolerable upper intake level (UL) of 65 mg daily for children 1 to 3 years, 110 mg daily for children 4 to 8 years, and 350 mg daily for children older than 8 years (7555,89396). ...when used parenterally and appropriately (96483).

CHILDREN: LIKELY UNSAFE
when used orally in excessive doses. Tell patients not to use doses above the tolerable upper intake level (UL). Higher doses can cause diarrhea and symptomatic hypermagnesemia including hypotension, nausea, vomiting, and bradycardia (7555,8095).

PREGNANCY AND LACTATION: LIKELY SAFE
when used orally and appropriately. Magnesium is safe for those pregnant and breast-feeding when used in doses below the tolerable upper intake level (UL) of 350 mg daily (7555).

PREGNANCY AND LACTATION: POSSIBLY SAFE
when prescription magnesium sulfate is given intramuscularly and intravenously prior to delivery for up to 5 days (12592,89397,99354,99355). However, due to potential adverse effects associated with intravenous and intramuscular magnesium, use during pregnancy is limited to patients with specific conditions such as severe pre-eclampsia or eclampsia. There is some evidence that intravenous magnesium can increase fetal mortality and adversely affect neurological and skeletal development (12590,12593,60818,99354,99355). However, a more recent analysis of clinical research shows that increased risk of fetal mortality seems to occur only in the studies where antenatal magnesium is used for tocolysis and not for fetal neuroprotection or pre-eclampsia/eclampsia (102457). Furthermore, antenatal magnesium does not seem to be associated with increased risk of necrotizing enterocolitis in preterm infants (104396). There is also concern that magnesium increases the risk of maternal adverse events. A meta-analysis of clinical research shows that magnesium sulfate might increase the risk of maternal adverse events, especially in Hispanic mothers compared to other racial and ethnic groups (60971,99319).

PREGNANCY AND LACTATION: POSSIBLY UNSAFE
when used orally in excessive doses. Tell patients to avoid exceeding the tolerable upper intake level (UL) of 350 mg daily. Taking magnesium orally in higher doses can cause diarrhea (7555). ...when prescription magnesium sulfate is given intramuscularly and intravenously prior to delivery for longer than 5 days (12592,89397,99354,99355). Maternal exposure to magnesium for longer than 5-7 days is associated with an increase in neonatal bone abnormalities such as osteopenia and fractures. The U.S. Food and Drug Administration (FDA) recommends that magnesium injection not be given for longer than 5-7 days (12590,12593,60818,99354,99355).

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LIKELY SAFE ...when used orally and appropriately. The pantothenic acid derivative calcium pantothenate has a generally recognized as safe (GRAS) status for use in food products (111258). While a tolerable upper intake level (UL) has not been established, pantothenic has been used in doses of 10-20 grams daily with apparent safety (15,6243,111258) ...when applied topically and appropriately, short-term. The Cosmetic Ingredient Review Expert Panel has concluded that pantothenic acid and its derivatives are safe for use in cosmetic products in concentrations up to 5.3% (111258). Gels or ointments containing a derivative of pantothenic acid, dexpanthenol, at concentrations of up to 5%, have been used safely for up to 30 days (67802,67806,67817).

POSSIBLY SAFE ...when applied intranasally and appropriately, short-term. A dexpanthenol nasal spray has been used with apparent safety up to four times daily for 4 weeks (67826). ...when applied in the eyes appropriately, short-term. Dexpanthenol 5% eyedrops have been used with apparent safety for up to 28 days (67783). ...when injected intramuscularly and appropriately, short-term. Intramuscular injections of dexpanthenol 500 mg daily for up to 5 days or 250 mg weekly for up to 6 weeks have been used with apparent safety (67822,111366).

CHILDREN: LIKELY SAFE
when used orally and appropriately (15,6243). Calcium pantothenate is generally recognized as safe (GRAS) when used as a food additive and in infant formula (111258). However, a tolerable upper intake level (UL) has not been established (15,6243). ...when applied topically and appropriately (67795,105190,111262). Infant products containing pantothenic acid and its derivatives have been used safely in concentrations of up to 5% for infant shampoos and 2.5% for infant lotions and oils. The Cosmetic Ingredient Review Expert Panel has concluded that pantothenic acid and derivatives are safe for use in topical infant products. (111258).

PREGNANCY: LIKELY SAFE
when used orally and appropriately. The daily adequate intake (AI) during pregnancy is 6 mg (3094).

LACTATION: LIKELY SAFE
when used orally and appropriately. The daily adequate intake (AI) during lactation is 7 mg (3094).

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POSSIBLY SAFE ...when an extract of reishi mushroom is used orally and appropriately for up to one year (12,5485,70767,70774,70786,70799,70800,70801,70802). ...when whole powdered reishi mushroom is used orally and appropriately for up to 16 weeks (70776,70799,70800,70801,91433,91435,91436,91437,108309).

PREGNANCY AND LACTATION:
Insufficient reliable information available; avoid using

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POSSIBLY SAFE ...when used orally and appropriately, short-term. There is some clinical research showing that taking rhodiola extract up to 300 mg twice daily has been used without adverse effects for up to 12 weeks (13109,16410,17616,71172,96459,102283,103269).

PREGNANCY AND LACTATION:
Insufficient reliable information available; avoid using.

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LIKELY SAFE ...when used orally, topically, intramuscularly, or intravenously and appropriately. Vitamin C is safe when taken orally in doses below the tolerable upper intake level (UL). Tell patients not to exceed the UL of 2000 mg daily (1959,4713,4714,4844). ...when used intravenously or intramuscularly and appropriately. Injectable vitamin C is an FDA-approved prescription product (15) and has been used with apparent safety in clinical trials up to 150 mg/kg daily for up to 4 days (114489) and up to 200 mg/kg daily for up to 2 days (114492).

POSSIBLY UNSAFE ...when used orally in excessive doses. Doses greater than the tolerable upper intake level (UL) of 2000 mg daily can significantly increase the risk of adverse effects such as osmotic diarrhea and gastrointestinal upset (4844).

CHILDREN: LIKELY SAFE
when used orally and appropriately (4844,10352,14443).

CHILDREN: POSSIBLY UNSAFE
when used orally in excessive amounts. Tell patients not to use doses above the tolerable upper intake level (UL) of 400 mg daily for children ages 1 to 3 years, 650 mg daily for children 4 to 8 years, 1200 mg daily for children 9 to 13 years, and 1800 mg daily for adolescents 14 to 18 years. Higher doses can cause osmotic diarrhea and gastrointestinal upset (4844).

PREGNANCY AND LACTATION: LIKELY SAFE
when used orally and appropriately (4844).

PREGNANCY AND LACTATION: POSSIBLY UNSAFE
when used orally in excessive doses. Tell patients over age 19 not to use doses exceeding the UL of 2000 mg daily when pregnant or breast-feeding and for those 14-18 years of age not to use doses exceeding 1800 mg daily when pregnant or breast-feeding. Higher doses can cause osmotic diarrhea and gastrointestinal upset. Large doses of vitamin C during pregnancy can also cause newborn scurvy (4844); avoid using.

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ANTIDIABETES DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = B Theoretically, taking ashwagandha with antidiabetes drugs might increase the risk of hypoglycemia.  Details There is preliminary clinical evidence suggesting that ashwagandha might lower blood glucose levels. Theoretically, ashwagandha might have additive effects when used with antidiabetes drugs and increase the risk of hypoglycemia (19274,90649,102685).

ANTIHYPERTENSIVE DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, taking ashwagandha with antihypertensive drugs might increase the risk of hypotension.  Details Animal research suggests that ashwagandha might lower systolic and diastolic blood pressure (19279). Theoretically, ashwagandha might have additive effects when used with antihypertensive drugs and increase the risk of hypotension.

BENZODIAZEPINES Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, taking ashwagandha might increase the sedative effects of benzodiazepines.  Details There is preliminary evidence that ashwagandha might have an additive effect with diazepam (Valium) and clonazepam (Klonopin) (3710). This may also occur with other benzodiazepines.

CNS DEPRESSANTS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, taking ashwagandha might increase the sedative effects of CNS depressants.  Details Ashwagandha seems to have sedative effects. Theoretically, this may potentiate the effects of barbiturates, other sedatives, and anxiolytics (3710).

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, ashwagandha might decrease the levels and clinical effects of CYP1A2 substrates.  Details In vitro research shows that ashwagandha extract induces CYP1A2 enzymes (111404).

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, ashwagandha might decrease the levels and clinical effects of CYP3A4 substrates.  Details In vitro research shows that ashwagandha extract induces CYP3A4 enzymes (111404).

HEPATOTOXIC DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, taking ashwagandha with hepatotoxic drugs might increase the risk of liver damage.  Details Ashwagandha has been linked to cases of acute hepatitis, liver failure, hepatic encephalopathy, autoimmune hepatitis, the need for liver transplantation, and death due to liver failure (102686,107372,110490,110491,111533,111535,112111,113610).

IMMUNOSUPPRESSANTS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, taking ashwagandha might decrease the effects of immunosuppressants.  Details Ashwagandha has demonstrated immunostimulant effects in humans (3710,3711,4114,11301,106786). Animal research has shown that ashwagandha can attenuate the immunosuppression caused by cyclophosphamide (3711,4114).

THYROID HORMONE Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Ashwagandha might increase the effects and adverse effects of thyroid hormone.  Details Concomitant use of ashwagandha with thyroid hormones may cause additive therapeutic and adverse effects. Preliminary clinical research and animal studies suggest that ashwagandha boosts thyroid hormone synthesis and secretion (19281,19282,97292). In one clinical study, ashwagandha increased triiodothyronine (T3) and thyroxine (T4) levels by 41.5% and 19.6%, respectively, and reduced serum TSH levels by 17.4% from baseline in adults with subclinical hypothyroidism (97292).

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ANTIDIABETES DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Theoretically, concomitant use of banaba and hypoglycemic drugs might have additive effects.  Details Human and animal research suggests that banaba can lower blood glucose levels (11954,11955,33554,92848,92849).

ANTIHYPERTENSIVE DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Theoretically, concomitant use of banaba and antihypertensive drugs might cause additive effects.  Details Human and animal research suggests that banaba can lower blood pressure (33557,92848,92849).

ORGANIC ANION-TRANSPORTING POLYPEPTIDE SUBSTRATES (OATP) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, concomitant use of banaba with substrates of OATP might reduce the bioavailability of the OATP substrate.  Details In vitro research shows that banaba inhibits OATP, particularly OATP2B1 (35450). OATPs are expressed in the small intestine and liver and are responsible for the absorption of drugs and other compounds.

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ALUMINUM Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Calcium citrate might increase aluminum absorption and toxicity. Other types of calcium do not increase aluminum absorption.  Details Calcium citrate can increase the absorption of aluminum when taken with aluminum hydroxide. The increase in aluminum levels may become toxic, particularly in individuals with kidney disease (21631). However, the effect of calcium citrate on aluminum absorption is due to the citrate anion rather than calcium cation. Calcium acetate does not appear to increase aluminum absorption (93006).

BISPHOSPHONATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = C Calcium reduces the absorption of bisphosphonates.  Details Advise patients to take bisphosphonates at least 30 minutes before calcium, but preferably at a different time of day. Calcium supplements decrease absorption of bisphosphonates (12937).

CALCIPOTRIENE (Dovonex) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Taking calcipotriene with calcium might increase the risk for hypercalcemia.  Details Calcipotriene is a vitamin D analog used topically for psoriasis. It can be absorbed in sufficient amounts to cause systemic effects, including hypercalcemia (12938). Theoretically, combining calcipotriene with calcium supplements might increase the risk of hypercalcemia.

CALCIUM CHANNEL BLOCKERS Interaction Rating = Minor Be watchful with this combination. Severity = Moderate •  Occurrence = Unlikely •  Level of Evidence = D Intravenous calcium may decrease the effects of calcium channel blockers; oral calcium is unlikely to have this effect.  Details Intravenous calcium is used to decrease the effects of calcium channel blockers in the management of overdose. Intravenous calcium gluconate has been used before intravenous verapamil (Isoptin) to prevent or reduce the hypotensive effects without affecting the antiarrhythmic effects (6124). But there is no evidence that dietary or supplemental calcium when taken orally interacts with calcium channel blockers (12939,12947).

CEFTRIAXONE (Rocephin) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = D Co-administration of intravenous calcium and ceftriaxone can result in precipitation of a ceftriaxone-calcium salt in the lungs and kidneys.  Details Avoid administering intravenous calcium in any form, such as parenteral nutrition or Lactated Ringers, within 48 hours of intravenous ceftriaxone. Case reports in neonates show that administering intravenous ceftriaxone and calcium can result in precipitation of a ceftriaxone-calcium salt in the lungs and kidneys. In several cases, neonates have died as a result of this interaction (15794,21632). So far there are no reports in adults; however, there is still concern that this interaction might occur in adults.

DIGOXIN (Lanoxin) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = B Using intravenous calcium with digoxin might increase the risk of fatal cardiac arrhythmias.  Details Hypercalcemia increases the risk of fatal cardiac arrhythmias with digoxin (12940). However, one retrospective analysis of clinical data suggests that intravenous calcium does not increase the risk of dysrhythmias or mortality in patients receiving digoxin (38960).

DILTIAZEM (Cardizem, others) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = D Theoretically, calcium may reduce the therapeutic effects of diltiazem.  Details Hypercalcemia can reduce the effectiveness of verapamil in atrial fibrillation (10574). Theoretically, calcium might increase this risk of hypercalcemia and reduce the effectiveness of diltiazem.

DOLUTEGRAVIR (Tivicay) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Calcium seems to reduce levels of dolutegravir.  Details Advise patients to take dolutegravir either 2 hours before or 6 hours after taking calcium supplements. Pharmacokinetic research suggests that taking calcium carbonate 1200 mg concomitantly with dolutegravir 50 mg reduces plasma levels of dolutegravir by almost 40%. Calcium appears to decrease levels of dolutegravir through chelation (93578).

ELVITEGRAVIR (Vitekta) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Calcium seems to reduce levels of elvitegravir.  Details Advise patients to take elvitegravir either 2 hours before or 2 hours after taking calcium supplements. Pharmacokinetic research suggests that taking calcium along with elvitegravir can reduce blood levels of elvitegravir through chelation (94166).

LEVOTHYROXINE (Synthroid, others) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Calcium seems to reduce the absorption and effectiveness of levothyroxine.  Details Advise patients to take levothyroxine and calcium supplements at least 4 hours apart. Calcium reduces levothyroxine absorption, probably by forming insoluble complexes (5082). Calcium carbonate supplements reduce effectiveness of levothyroxine in patients with hypothyroidism (5081,5082,6137).

LITHIUM Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Theoretically, concomitant use of calcium and lithium may increase this risk of hypercalcemia.  Details Clinical research suggests that long-term use of lithium may cause hypercalcemia in 10% to 60% of patients (38953). Theoretically, concomitant use of lithium and calcium supplements may further increase this risk.

QUINOLONE ANTIBIOTICS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Calcium seems to reduce the absorption of quinolone antibiotics.  Details Advise patients to take oral quinolones at least 2 hours before or 4-6 hours after calcium supplements or calcium-fortified foods. Taking calcium at the same time as oral quinolones can reduce quinolone absorption. Calcium binds to quinolones in the gut (4412,10339,21638,38570).

RALTEGRAVIR (Isentress) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = B Calcium may reduce levels of raltegravir.  Details Pharmacokinetic research shows that taking a single dose of calcium carbonate 3000 mg along with raltegravir 400 mg twice daily modestly decreases the mean area under the curve of raltegravir, but the decrease does not necessitate a dose adjustment of raltegravir (94164). However, a case of elevated HIV-1 RNA levels and documented resistance to raltegravir has been reported for a patient taking calcium carbonate 1 gram three times daily plus vitamin D3 (cholecalciferol) 400 IU three times daily in combination with raltegravir 400 mg twice daily for 11 months. It is thought that calcium reduced raltegravir levels by chelation, leading to treatment failure (94165).

SOTALOL (Betapace) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Calcium seems to reduce the absorption of sotalol.  Details Advise patients to separate doses by at least 2 hours before or 4-6 hours after calcium. Calcium appears to reduce the absorption of sotalol, probably by forming insoluble complexes (10018).

TETRACYCLINE ANTIBIOTICS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = C Calcium seems to reduce the absorption of tetracycline antibiotics.  Details Advise patients to take oral tetracyclines at least 2 hours before, or 4-6 hours after calcium supplements. Taking calcium at the same time as oral tetracyclines can reduce tetracycline absorption. Calcium binds to tetracyclines in the gut (1843).

THIAZIDE DIURETICS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = C Taking calcium along with thiazides might increase the risk of hypercalcemia and renal failure.  Details Thiazides reduce calcium excretion by the kidneys (1902). Using thiazides along with moderately large amounts of calcium carbonate increases the risk of milk-alkali syndrome (hypercalcemia, metabolic alkalosis, renal failure). Patients may need to have their serum calcium levels and/or parathyroid function monitored regularly.

VERAPAMIL (Calan, others) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = D Theoretically, calcium may reduce the therapeutic effects of verapamil.  Details Hypercalcemia can reduce the effectiveness of verapamil in atrial fibrillation (10574). Theoretically, use of calcium supplements may increase this risk of hypercalcemia and reduce the effectiveness of verapamil.

(Read more about CALCIUM)

ANTIDIABETES DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = A Theoretically, chromium may have additive effects with antidiabetic agents and increase the risk of hypoglycemia.  Details Some research shows that taking chromium might lower blood glucose levels, especially in patients with poorly controlled type 2 diabetes (7137,14440,15169,94234,95097,95098,98687).

ASPIRIN Interaction Rating = Minor Be watchful with this combination. Severity = Insignificant •  Occurrence = Possible •  Level of Evidence = D Theoretically, aspirin might increase chromium absorption.  Details Animal research suggests that aspirin may increase chromium absorption and chromium levels in the blood (21055).

INSULIN Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Theoretically, concomitant use of chromium and insulin might increase the risk of hypoglycemia.  Details In clinical research, chromium has been shown to increase insulin sensitivity (1952,14440,95095),

LEVOTHYROXINE (Synthroid, others) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Chromium might bind levothyroxine in the intestinal tract and decrease levothyroxine absorption.  Details Clinical research in healthy volunteers shows that taking chromium picolinate 1000 mcg with levothyroxine 1 mg decreases serum levels of levothyroxine by 17% when compared to taking levothyroxine alone (16012). Advise patients to take levothyroxine at least 30 minutes before or 3-4 hours after taking chromium.

NONSTEROIDAL ANTI-INFLAMMATORY DRUGS (NSAIDs) Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D NSAIDs might increase chromium levels in the body.  Details Drugs that are prostaglandin inhibitors, such as NSAIDs, seem to increase chromium absorption and retention (7135).

(Read more about CHROMIUM)