Brain Booster [Discontinued] by Vital Vitamins

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Alzheimer disease. It is unclear if oral bacopa is beneficial in patients with Alzheimer disease. Details: A small clinical study in patients with Alzheimer disease or mild cognitive impairment shows that taking bacopa 300 mg daily for 12 months does not improve measures of cognitive function or memory when compared with donepezil or baseline measures (109623).
• Attention deficit-hyperactivity disorder (ADHD). It is unclear if oral bacopa is beneficial in children with ADHD. Details: A small clinical study in boys 6-14 years of age with symptoms consistent with ADHD but without an official diagnosis shows that taking a specific bacopa supplement (KeenMind - CDRI 08, Flordis) for 14 weeks does not improve symptoms of ADHD but improves some cognitive outcomes including error-making, cognitive flexibility, executive functioning, and sleep when compared with placebo. Bacopa 160 mg was given once daily in those weighing 20-35 kg and twice daily in those over 35 kg (109625). However, another small, open-label study in children aged 6-12 years with ADHD shows that taking a different bacopa supplement (BacoMind, Natural Remedies), 225 mg daily for 6 months, improves symptoms such as restlessness, impulsivity, learning problems, and attention deficit when compared to baseline (97603). The validity of these findings is limited by the lack of blinding or comparator group.
• Back pain. Although there is interest in using oral bacopa for back pain, there is insufficient reliable information about the clinical effects of bacopa for this condition.
• Cognitive function. Bacopa seems to improve some measures of cognitive function, but data are conflicting. Details: A meta-analysis of 9 small clinical studies, along with more recent clinical research, shows that taking bacopa 300-600 mg daily for at least 12 weeks is not associated with improved measures of cognition including working memory, learning rate, recognition of pictures and words, reaction time, or attention when compared with placebo. However, subgroup analysis of this meta-analysis and another small clinical study show some evidence of improved reaction times, verbal learning, total recall, retention, memory, and information processing in healthy adults when compared with placebo (10058,17946,33287,97605,109624,111520). In children aged 6-8 years old, a very small clinical study shows that taking a syrup containing bacopa extract 350 mg three times daily for 3 months improves visual motor function and immediate memory when compared to baseline (33304). The validity of this finding is limited by the lack of a statistical comparison to the placebo group. Bacopa has also been studied in combination with other ingredients. A study in healthy adults aged 18-60 years shows that taking a single dose of a combination of bacopa 300 mg, American ginseng 100 mg, and coffee fruit extract 100 mg (Bacognize) improves some measures of working memory and attention by a small amount at 45 minutes when compared with placebo (103375). It is unclear if these effects are due to bacopa, other ingredients, or the combination. In contrast, a moderate-sized study in healthy, middle-aged adults shows that taking a combination product containing whole plant bacopa 7.5 grams, gingko biloba, and group B vitamins for 12 weeks does not improve measures of memory, attention, cognition, mood, or stress reactivity when compared with placebo. Subgroup analysis shows a possible benefit of bacopa supplementation on measures of attention in those with an optimal diet at baseline (111334).
• Cognitive impairment. It is unclear if oral bacopa is beneficial in patients with cognitive impairment. Details: A small clinical study in patients with mild cognitive impairment or Alzheimer disease shows that taking bacopa 300 mg daily for 12 months does not improve measures of cognitive function or memory when compared with donepezil or baseline (109623).
• Congestive heart failure (CHF). Although there is interest in using oral bacopa for CHF, there is insufficient reliable information about the clinical effects of bacopa for this condition.
• Depression. It is unclear if oral bacopa is beneficial in patients with depression. Details: Preliminary clinical research in adults with depression who have not responded to citalopram 40 mg daily shows that adding bacopa extract 300 mg twice daily for 4 weeks improves scores on depression rating scales when compared with citalopram alone (103378).
• Hypertension. Although there is interest in using oral bacopa for hypertension, there is insufficient reliable information about the clinical effects of bacopa for this condition.
• Insomnia. Although there is interest in using oral bacopa for insomnia, there is insufficient reliable information about the clinical effects of bacopa for this condition.
• Irritable bowel syndrome (IBS). Bacopa has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in patients with diarrhea-predominant IBS shows that taking a combination of bacopa and bael (Aegel marmalos) reduces symptoms in 65% of patients, compared with 78% of patients taking clidinium bromide, chlordiazepoxide, and blond psyllium, and 33% taking placebo. Neither treatment is more effective than placebo for preventing relapses (10059).
• Parkinson disease. It is unclear if oral bacopa is beneficial in patients with Parkinson disease. Details: A very small study in older adults with Parkinson disease taking levodopa shows that taking a specific bacopa extract (Cognitus, Herbarium) 225 mg or 450 mg daily for 90 days does not improve Parkinsonian or systemic symptoms, motor activity, emotional function, or social outcomes when compared with placebo (111523). The validity of these findings is limited by a small sample size and lack of randomization.
• Rheumatoid arthritis (RA). Although there is interest in using oral bacopa for RA, there is insufficient reliable information about the clinical effects of bacopa for this condition.
• Sexual dysfunction. Although there is interest in using oral bacopa for sexual dysfunction, there is insufficient reliable information about the clinical effects of bacopa for this condition.
• Smoking cessation. Oral bacopa has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A moderate-sized clinical study in adults in India with a history of smoking 5 or more cigarettes daily for at least 3 years shows that taking a specific combination product containing bacopa 100 mg, ashwagandha, clove, ginger, cowhage, turmeric, and other herbal extracts (Smotect , Smotect India) twice daily for 3 months reduces the number of cigarettes smoked daily and alveolar carbon monoxide and carboxyhemoglobin levels but does not improve lung capacity when compared with placebo (112115). It is unclear if these effects are due to bacopa, other ingredients, or the combination. More evidence is needed to rate bacopa for these uses.

(Read more about BACOPA)

LIKELY INEFFECTIVE

• Alzheimer disease. Oral deanol does not appear to improve memory in individuals with Alzheimer disease. Details: Two very small clinical trials in patients with Alzheimer disease show that taking deanol, titrated up to a dose of 600 mg three times daily, for 4-5 weeks does not seem to improve memory or other cognitive functions when compared with placebo (1680,1681).
• Tardive dyskinesia. Oral deanol does not improve symptoms of tardive dyskinesia. Details: Meta-analyses and individual clinical studies show that taking deanol 1-2 grams daily for up to 1 month does not improve symptoms of tardive dyskinesia when compared with baseline or placebo (1672,1673,1674,1675,1676,1803,1804).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Aging. Although there has been interest in using oral deanol to prevent aging and extend life span, there is insufficient reliable information about the clinical effects of deanol for this purpose.
• Aging skin. Although there has been interest in using topical deanol for aging skin, there is insufficient reliable information about the clinical effects of deanol for this purpose.
• Athletic performance. Oral deanol has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in healthy males shows that taking deanol in combination with ginseng, vitamins, and minerals for 6 weeks improves exercise performance by increasing total work load and maximal oxygen consumption during exercise (1671). It is unclear if these findings are due to deanol, other ingredients, or the combination.
• Attention deficit-hyperactivity disorder (ADHD). It is unclear if oral deanol is beneficial in children with ADHD. Details: Clinical research on the use of deanol in children with ADHD-like symptoms is mixed (1669,1677,1679,92702). One moderate sized clinical study in children with behavioral and learning disorders, most of whom also had hyperactivity, shows that taking deanol 500 mg daily for 3 months significantly improves performance on various psychometric tests when compared with placebo. The improvements seen with deanol were similar to those reported with methylphenidate 40 mg daily (1679). Another small study in children 6-12 years of age with behavior problems consistent with ADHD shows that taking deanol 300-500 mg daily for 12 weeks improves some measures of performance when compared with placebo (92702). However, other research shows that deanol does not improve ADHD symptoms in children (1669,1677). The children evaluated in each of these studies were not diagnosed with ADHD using current diagnostic guidelines, limiting the applicability of these results in clinical practice.
• Autism spectrum disorder. Although there has been interest in using oral deanol for autism spectrum disorder, there is insufficient reliable information about the clinical effects of deanol for this purpose.
• Cognitive function. Although there has been interest in using oral deanol to improve cognitive function, there is insufficient reliable information about the clinical effects of deanol for this purpose. More evidence is needed to rate deanol for these uses.

(Read more about DEANOL)

POSSIBLY EFFECTIVE

• Anxiety. Oral ginkgo seems to modestly reduce anxiety symptoms. Details: Clinical research shows that taking a specific ginkgo extract called EGb 761 (Dr. Willmar Schwabe Pharmaceuticals) for 4 weeks can modestly reduce symptoms of anxiety in a greater percentage of adults with generalized anxiety disorder or adjustment disorder with anxious mood when compared with placebo. After 4 weeks of treatment, a reduction in anxiety rating score of at least 50% was seen in 44% of patients treated with 480 mg daily, 39% of patients treated with 240 mg daily, and 22% of patients treated with placebo (15578). It is unclear whether these effects would persist when taken for longer than 4 weeks. This study was also included in a meta-analysis that performed indirect comparisons of multiple herbs for the treatment of anxiety. This analysis suggests that taking ginkgo may reduce anxiety scores modestly more than kava (110711). However, the interpretation of these results is limited by the small amount of data available for ginkgo.
• Dementia. Oral ginkgo 240 mg seems to improve symptoms of various types of dementia, but lower doses are not always effective. Oral ginkgo does not seem to prevent or slow down the progression of dementia. Details: Most evidence shows that higher doses of a specific ginkgo extract (EGb761) modestly improve symptoms of Alzheimer, vascular, or mixed dementias. Meta-analyses of clinical research in patients with dementia show that taking ginkgo, usually 240 mg daily for 24 weeks, modestly improves cognition and activities of daily living when compared with placebo. When analyses pooled studies testing low-dose (120 mg) and high-dose (240 mg) ginkgo together, the benefit was not always present (87855,87819,87851,87866,88006,89713,102183,102185,102186,103572)(111333). Although most clinical trials show benefit, there are some clinical trials with conflicting findings, suggesting inconsistent and unpredictable effects (16637,87726). There has been some debate about whether ginkgo is more effective in dementia patients who have neuropsychiatric symptoms. Most clinical research shows that this is not the case. However, high-dose ginkgo 240 mg daily seems to modestly relieve most neuropsychiatric symptoms other than psychosis (17717,87794,87897,102185,102187). Few clinical studies compare ginkgo leaf extract to conventional drugs such as cholinesterase inhibitors. Some preliminary comparative studies show that taking a specific ginkgo leaf extract called EGb 761 (Dr. Willmar Schwabe Pharmaceuticals) 160-240 mg daily for 22-24 weeks seems to be comparable to donepezil (Aricept) 5-10 mg daily for mild to moderate Alzheimer disease (14499,87826). Similarly, a clinical study in patients with Alzheimer disease or mild cognitive impairment shows that taking ginkgo extract 150 mg three times daily for 6 months seems to be comparable to donepezil 5 mg daily for improvement of cognitive scores (106611). However, indirect comparisons suggest that ginkgo leaf extract might be less effective than the conventional drugs donepezil, tacrine (Cognex), rivastigmine (Exelon), and other cholinesterase inhibitors (6224,6490,11981,89710). Also, some studies show that taking ginkgo in combination with conventional medications for 12-24 weeks does not improve cognitive scores by a clinically meaningful extent when compared with conventional medications alone (95902,106611). However, a meta-analysis of 17 mostly small, low quality clinical studies in patients with Alzheimer disease, that includes some of these studies, shows that taking ginkgo in combination with donepezil for 3-9 months modestly improves cognitive scores when compared with donepezil alone. Adding ginkgo may also improve activities of daily living scores (111332). Another meta-analysis of mostly small clinical studies in adults with vascular dementia also shows that taking ginkgo extract orally or intravenously daily for 4-12 weeks, in addition to donepezil, moderately improves cognitive scores and functional scores when compared with donepezil alone (114767). However, the validity of these findings is limited by the heterogeneity of the included studies, which utilized various doses and forms of ginkgo. Ginkgo does not appear to be beneficial for preventing or slowing the progression of dementia. Epidemiologic research shows that taking ginkgo extract is not associated with a decreased risk of developing dementia in elderly patients with memory impairment (14812). Three large-scale clinical trials also show that taking ginkgo extract 120 mg twice daily does not reduce the risk of developing all-cause dementia or Alzheimer disease in elderly patients with normal cognitive function or in those with mild cognitive impairment (16634,87848,87904). In addition, taking ginkgo extract does not seem to prevent disease progression in Alzheimer patients (89713). Most of the clinical studies on the effectiveness of ginkgo leaf for dementia have used the standardized extracts EGb 761 (Dr. Willmar Schwabe Pharmaceuticals and Ipsen) and LI 1370 (Lichtwer Pharma). These two extracts are similar and prepared to contain approximately 24% to 25% flavone glycosides and 6% terpene lactones. Other products with similar ingredients include Ginkai (Lichtwer Pharma), Ginkgo 5 (Pharmline), Ginkgold and Ginkgo (Nature's Way), and Quanterra Mental Sharpness (Warner-Lambert).
• Hearing loss. Intravenous ginkgo appears to improve hearing loss when used in conjunction with corticosteroids. The effectiveness of oral ginkgo is unclear. Details: A meta-analysis of randomized controlled trials (RCTs) in adults with sudden hearing loss shows that using intravenous ginkgo leaf extract 40-175 mg daily, in addition to corticosteroids, for 5-14 days increases clinical cure rates by 1.3 times that of corticosteroids alone. Ginkgo leaf in combination with corticosteroids also improved hearing sensitivity (107360). Another meta-analysis of 27 mostly low-quality RCTs in patients with sudden hearing loss, that includes some of the same studies as the prior analysis, shows that adding ginkgo extract to usual care for 1-14 days leads to improvement or no further deterioration in 91% of patients when compared with 75% of patients receiving usual care (111339). However, the interpretation of these results is limited by unclear ginkgo dosing and inclusion of studies that administered ginkgo orally, as an injection, or unknown route. In addition, usual care treatments were not described. In addition, one clinical study in patients with short-term idiopathic hearing loss shows that oral ginkgo leaf extract 120 mg twice daily for 8 weeks might improve hearing recovery rates when compared with ginkgo leaf extract 12 mg twice daily (8543). However, there was a high spontaneous recovery rate in both groups, so it is unclear how much benefit, if any, can be attributed to ginkgo leaf extract.
• Premenstrual syndrome (PMS). Oral ginkgo seems to reduce symptoms of PMS. Details: Taking ginkgo leaf extract orally 80 mg twice daily or 40 mg three times daily seems to produce significant relief in breast tenderness and other physical and psychological symptoms associated with PMS when started during the 16th day of the menstrual cycle and continued until the 5th day of the following cycle for up to two cycles (6229,87839). Specific ginkgo leaf extracts that have been assessed for this condition include Ginko T.D. (Tolidaru Pharmaceuticals) and EGb 761, which is an ingredient in several commercial products including Tebonin (Dr. Willmar Schwabe Pharmaceuticals), Tanakan (Ipsen), and Quanterra Mental Sharpness (Warner-Lambert).
• Schizophrenia. Oral ginkgo seems to reduce total and negative symptoms of schizophrenia, and may be beneficial for reducing antipsychotic-associated adverse effects. Details: Taking a standardized ginkgo leaf extract EGb 761 (Yi Kang Ning, Yang Zi Jiang Pharmaceuticals Ltd.), 120-360 mg orally daily in addition to standard antipsychotic medications (such as olanzapine, clozapine, or haloperidol) for 8-16 weeks, can reduce total and negative symptoms of schizophrenia when compared to treatment with antipsychotic medications alone (87844,95901). Guidelines from The World Federation of Societies of Biological Psychiatry (WFSBP) and Canadian Network for Mood and Anxiety Treatments (CANMAT) Taskforce state that ginkgo extract at doses of 120-360 mg daily is weakly recommended for adjunctive use in schizophrenia, primarily for negative symptoms (110318). Treatment with ginkgo leaf extract might also reduce anticholinergic side effects such as thirst and constipation and adverse behavioral, cardiovascular, and nerve symptoms associated with antipsychotic treatment (87708,95901). Additional clinical research is needed to determine the role of ginkgo on antipsychotic-associated adverse effects.
• Stroke. Oral and intravenous ginkgo seem to improve recovery from stroke; intravenous ginkgo might be more effective. Details: While some individual studies show conflicting results, meta-analyses of small, low-quality clinical trials in patients recovering from ischemic stroke show that oral or intravenous ginkgo extract along with conventional therapy seems to improve neurologic function and activities of daily living scores, but does not improve quality of life or reduce the risk of recurrent stroke or death, when compared with conventional therapy alone (14435,102883,102884,107452). However, the overall methodological quality of the meta-analyses is described as critically low, with a high risk of bias (113783). One meta-analysis shows that intravenous ginkgo extract is associated with greater improvements in these measures than oral ginkgo extract (102884). Ginkgo diterpene lactone meglumine (GDLM) is a derivative of ginkgo composed of active ingredients ginkgolides A, B, and K that has been investigated for the treatment of acute ischemic stroke both as monotherapy and in combination with thrombolysis. Large clinical trials in adults with moderate acute ischemic stroke show that giving an intravenous infusion of GDLM 25 mg daily, initiated within 48 hours of symptom onset and continuing for up to 14 days, increases the proportion of patients achieving a favorable outcome, defined as a score of 0 or 1 on the modified Rankin Scale (mRS) on day 90, by 15% when compared with placebo. About 62% of patients treated with GDLM show clinically significant improvement in Montreal Cognitive Assessment scores, compared with 56% of those on placebo. The most significant improvements occur in measures of language and visuo-spatial and executive function (111693,113784). Additionally, a meta-analysis shows that combination therapy with GDLM and tissue plasminogen activator (rTPA) is associated with greater improvements than conventional treatments alone or other traditional Chinese herbal medicines that contain ginkgo (i.e. ginaton, danhong, xueshuantong, and shuxuening injections). This specific formulation also appears to be more effective than intravenous ginkgolides or ginkgolide B; however, investigators did not provide a statistical comparison of outcomes between groups, limiting the validity of this finding (108610). Another meta-analysis shows that intravenous administration of ginkgo leaf extract plus dipyridamole 10-40 mL daily for 14-30 days along with conventional therapy also improves neurologic function and activities of daily living when compared with conventional therapy alone (102882). In patients not treated with thrombolytics, a small clinical study in adults in China shows that administering ginkgo diterpene lactone meglumine 25 mg intravenously daily for 14 days, starting within 48 hours after an ischemic stroke, in addition to aspirin 100 mg daily for 90 days, led to improvement in scores related to stroke severity or the degree of disability at 90 days in 94% of patients when compared with 83% of patients treated with aspirin alone (111340). However, the patients in this study had minor or moderate strokes; these results may not apply to patients with more severe strokes. In patients with hemorrhagic stroke, preliminary clinical research shows that daily intravenous administration of ginkgo extract (Taiwan Jisheng Chemical Pharmaceutical Co., Ltd.) 17.5 grams for 2 weeks, in conjunction with routine treatment and intravenous oxiracetam 6 grams, reduces cerebral edema and bleeding and modestly improves recovery of neurological and cognitive function and activities of daily living when compared with oxiracetam plus routine care or routine care alone (103573). A meta-analysis of 19 Chinese clinical trials in patients with hemorrhagic stroke shows that treatment with ginkgo leaf extracts for 7-20 days in combination with standard treatment is associated with lower NIH and Chinese stroke scale scores, lower residual hematoma and cerebral edema volumes, lower serum levels of inflammatory factors, and higher cognitive function and activity of daily living scores, when compared with standard treatment alone, although with considerable heterogeneity in the results (113781).
• Tardive dyskinesia. Oral ginkgo seems to reduce the severity of tardive dyskinesia in schizophrenic patients being treated with antipsychotic medications. Details: Clinical research shows that taking a specific ginkgo extract called EGb 761 (Yi Kang Ning, Yang Zi Jiang Pharmaceuticals Ltd.) 80 mg three times daily for 12 weeks can reduce the severity of tardive dyskinesia by at least 30% when compared with placebo in schizophrenic patients being treated with antipsychotic medications (87864).
• Vascular dementia. Oral ginkgo extract seems to modestly improve scores related to cognitive function in patients with this condition. Details: A meta-analysis of small randomized controlled trials in adults with vascular dementia shows that taking ginkgo extract orally or intravenously daily for 4-12 weeks, in addition to donepezil, moderately improves cognitive scores and functional scores when compared with donepezil alone (114767). However, the results of this study are limited by high heterogeneity. In addition, these trials do not report standard doses of ginkgo. A small clinical study in patients with vascular dementia shows that taking a specific extract of ginkgo EGb 761 (Dr. Willmar Schwabe Pharmaceuticals) 240 mg daily for 24 weeks modestly improves scores related to cognitive function, neuropsychiatric symptoms, and activities of daily living when compared with placebo (17191). A preliminary open-label clinical study in patients aged 50 years or older in China shows that taking the same ginkgo extract 240 mg daily for 24 weeks, starting within 7-14 days after an ischemic stroke, modestly improves scores related to cognitive function and mental health, but not neuropsychiatric symptoms, when compared with standard care (111335). However, the patients in this study had minor strokes; these results may not apply to patients with more severe strokes. Ginkgo has also been evaluated in combination with other ingredients to treat vascular dementia. A small clinical study in patients aged 60 years or older with vascular dementia shows that taking a supplement containing extracts of ginkgo, Panax ginseng, and saffron 60 mg three times daily for 16 weeks modestly improves some cognitive function scores, caregiver assessed activities of daily living, and patient-reported quality of life. However, these effects were not maintained after patients stopped taking the supplement (111336).
• Vertigo. Oral ginkgo seems to improve symptoms of vertigo in people with vestibular disorders. It is unclear if it is beneficial for vertigo caused by cerebral arteriosclerosis. Details: Taking ginkgo leaf extract 120-160 mg daily orally seems to improve symptoms of vertigo and equilibrium disorders (5721,6220,6221,107359,108608). There is evidence from two clinical studies that ginkgo leaf extract (EGb 761) for 3 months is significantly more effective than placebo (6220), and possibly as effective as betahistine, for improving vertigo and dizziness caused by vascular vestibular disorders and vestibular disorders of unknown origin (6220,6221). However, adding balance training to treatment with ginkgo leaf extract (EGb 761) orally 80 mg twice daily for 3 months is no better than taking ginkgo leaf extract alone (107359). Ginkgo has also been evaluated in patients with vertigo caused by mild cerebral arteriosclerosis. A clinical study in this population shows that taking oral ginkgo leaf extract (Zhejiang Jiu Xu Pharmaceutical Co, Ltd) 40 mg three times daily for 6 weeks improves scores of traditional Chinese medicine symptom pattern, specifically dizziness, blurry vision, headache, and amnesia, but does not impact Dizziness Handicap Inventory scores, when compared with naoxinqing (NXQ), a standardized herbal product that contains Japanese persimmon leaf extract (108608). The validity of this study is limited due to the lack of comparison to placebo or an accepted conventional treatment.

POSSIBLY INEFFECTIVE

• Age-related cognitive decline. Most research shows that oral ginkgo does not improve symptoms of age-related cognitive impairment. Details: While some preliminary clinical research shows a modest benefit of ginkgo leaf extract on memory and cognitive function in patients with age-related memory or thinking impairment (5717,6216,89712), most clinical research shows that taking ginkgo leaf extract orally does not improve memory or attention in elderly individuals with normal mental function (5718,8586,8587,8588,87848). Clinical research also shows that taking a standardized ginkgo leaf extract (Thorne Research Inc.) 240 mg daily for 3.5 years does not reduce the risk of developing age-related cognitive impairment in elderly patients aged 85 years and older who have normal cognitive function (16635).
• Antidepressant-induced sexual dysfunction. Most research shows that oral ginkgo does not improve symptoms of sexual dysfunction in people using antidepressants. Details: Although some preliminary clinical research shows that taking ginkgo leaf extract orally might help sexual dysfunction caused by antidepressant therapy (3965,3967), subsequent research indicates that it not likely to be beneficial (207,3966,3969,10893,14383).
• Cardiovascular disease (CVD). Oral ginkgo does not seem to prevent CVD. Details: A large-scale randomized trial shows that taking a specific ginkgo leaf extract called EGb 761 (Dr. Willmar Schwabe Pharmaceuticals) 240 mg daily orally for an average of 6.1 years does not reduce the risk of myocardial infarction, angina, stroke, CVD-related hospitalization, or mortality in elderly patients when compared with placebo (17402).
• Chemotherapy-related cognitive impairment. Oral ginkgo does not seem to improve symptoms of cognitive impairment in people using chemotherapy. Details: Clinical research shows that taking a specific ginkgo leaf extract called EGb 761 (Dr. Willmar Schwabe Pharmaceuticals) 60 mg twice daily, starting prior to the second cycle of chemotherapy and continuing until one month after chemotherapy completion, does not prevent chemotherapy-related cognitive dysfunction when compared with placebo in chemotherapy-naïve breast cancer patients (89701).
• Hypertension. Oral ginkgo does not seem to reduce blood pressure in older, hypertensive patients. Details: A meta-analysis of low-quality research in subjects with hypertension shows that taking ginkgo orally daily for 4-26 weeks modestly improves systolic and diastolic blood pressure when compared with control (114766). However, the validity of this study is limited by high heterogeneity, differing co-interventions, including known antihypertensives, and differing controls. Other clinical research shows that taking a standardized ginkgo leaf extract called EGb 761 (Dr. Willmar Schwabe Pharmaceuticals) 240 mg daily for up to 6 years does not reduce blood pressure when compared with placebo in hypertensive patients aged 75 years or older (87853).
• Multiple sclerosis (MS). Most research shows that oral ginkgo does not improve symptoms of MS. Details: Most clinical research shows that taking ginkgo leaf extract or ginkgolide B, a constituent of ginkgo leaf extract, does not improve cognition or disability in patients with MS (87739,87787,87903,87947). However, a single preliminary clinical study shows that taking a standardized ginkgo leaf extract called EGb 761 (Dr. Willmar Schwabe Pharmaceuticals) may improve processing speed when compared with placebo in patients with multiple sclerosis (89705).
• Tinnitus. Most research shows that oral ginkgo does not improve symptoms of tinnitus. Details: Taking ginkgo leaf extract orally does not seem to improve symptoms of tinnitus. Although some studies have shown benefit, the majority of the clinical evidence indicates that ginkgo leaf extract is not consistently effective for patients with tinnitus (221,910,5721,6218,6219,9871,87754,87901,110093,111337)(111513).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Age-related macular degeneration (AMD). It is unclear if oral ginkgo is beneficial in AMD. Details: Preliminary clinical research suggests that taking a specific ginkgo leaf extract (EGb 761) 60-240 mg orally in divided doses for up to 6 months might improve symptoms of AMD (6227,6228,11797). There is limited evidence that ginkgo leaf extract might significantly improve distance vision in patients with AMD (6227).
• Aging. Although there has been interest in using oral ginkgo for aging, there is insufficient reliable information about the clinical effects of ginkgo for this condition.
• Allergic rhinitis (hay fever). Topical ginkgo has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in patients with seasonal allergic conjunctivitis shows that applying two drops of specific eye drops (Trium, SOOFT) containing ginkgo extract 0.05% and hyaluronic acid 0.15%, three times daily for one month can decrease redness by 80%, discharge by 40%, and swelling by 10% when compared to using eye drops with hyaluronic acid alone (87829).
• Altitude sickness. Research on the use of oral ginkgo for altitude sickness is conflicting. Details: Some research shows that taking ginkgo extract 80-120 mg twice daily for 4 days before the ascent to an altitude of 4300-5400 meters significantly reduces the occurrence of symptoms of acute altitude sickness, including headache, fatigue, dyspnea, nausea, and vomiting, when compared with placebo (6230,87827). A standardized ginkgo leaf extract called EGb 761, 160 mg in two divided doses daily, was used in one of these studies (6230). However, a large-scale trial using a different ginkgo extract (GK501, Pharmaton Natural Health Products) 120 mg twice daily for 1-2 days before the climb from an altitude of 4280 meters to 4928 meters, shows that ginkgo extract has no effect on preventing altitude sickness (11766). Also, another small study suggests that taking ginkgo extract 120 mg twice daily for 3 days before an ascent does not reduce altitude sickness when compared with placebo (87827). The conflicting results may be due to differences in starting baseline altitudes before ascent, duration of the pre-treatment period, or the source of the ginkgo product.
• Angina. Some low-quality evidence suggests that oral ginkgo may reduce angina symptoms when taken in addition to standard of care. Details: A large meta-analysis of variable-quality studies in patients with unstable angina shows that taking ginkgo orally or intravenously for up to 12 weeks modestly improves angina symptoms when compared with control (114768). However, the results of this study are limited by the heterogeneity of included studies, including different control treatments. A small clinical study in patients with stable angina shows that taking ginkgo extract formulated with a polyethylene glycol matrix to improve bioavailability, 315 mg three times daily with standard therapy for 12 weeks, does not improve the overall Seattle Angina Questionnaire score when compared with placebo, although there is a trend towards a reduction in angina attack frequency (113782).
• Asthma. Oral ginkgo has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Clinical research shows that a taking two capsules of a specific combination product (AKL1, AKL International Ltd.) containing ginkgo extract 130 mg/capsule, ginger 100 mg/capsule, and Picrorhiza 270 mg/capsule twice daily for 12 weeks does not improve lung function, respiratory symptoms, or quality of life when compared with placebo in adult patients with asthma (87786).
• Attention deficit-hyperactivity disorder (ADHD). It is unclear if oral ginkgo is beneficial in ADHD. Details: One clinical study shows that taking a standardized ginkgo extract (Ginko T.D., Tolidaru Pharmaceuticals) 80-120 mg daily for 6 weeks is less effective than methylphenidate 20-30 mg daily in children aged 6-14 years with newly diagnosed ADHD. Only 8% of children taking ginkgo extract had at least a 40% improvement in a teacher/parent ADHD rating scale, compared with 64% in children taking methylphenidate (17112). Another clinical study in children aged 6-12 years with ADHD shows that taking the same standardized ginkgo extract 80-120 mg daily in combination with methylphenidate 20-40 mg daily for 6 weeks does not improve parent- or teacher-rated ADHD scores by a clinically meaningful amount when compared with methylphenidate alone (95669). However, one preliminary clinical study shows that taking a specific combination product (AD-fX, CV Technologies) containing ginkgo leaf extract 100 mg, in combination with American ginseng extract 400 mg, in two divided doses for 4 weeks might significantly improve ADHD symptoms such as anxiety, hyperactivity, and impulsivity in children aged 3-17 years (8235). Guidelines from The World Federation of Societies of Biological Psychiatry (WFSBP) and Canadian Network for Mood and Anxiety Treatments (CANMAT) Taskforce state that ginkgo extract at doses of 80-120 mg daily is not currently recommended for monotherapy or adjunctive use in children with ADHD due to mixed evidence (110318).
• Autism spectrum disorder. It is unclear if oral ginkgo is beneficial in children with autism. Details: A small clinical trial shows that taking a specific ginkgo extract (Ginko T.D., Tolidaru Pharmaceuticals) 80-120 mg daily for 10 weeks along with risperidone 1-3 mg daily does not improve symptoms of autism when compared with risperidone alone in children aged 4-12 years (89708).
• Bronchitis. Although there has been interest in using oral ginkgo for bronchitis, there is insufficient reliable information about the clinical effects of ginkgo for this condition.
• Chronic fatigue syndrome (CFS). Oral ginkgo has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in adults with CFS shows that taking ginkgo leaf 120-180 mg in combination with Cistanche tubulosa root 300-450 mg orally daily for 60 days improves fatigue scores by 16% to 19% when compared with placebo. Taking this combination also improved quality of life scores when compared with placebo (107361).
• Chronic kidney disease (CKD). There is limited evidence on the intravenous use of ginkgo leaf extract in adults with hypertensive nephropathy. It has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small meta-analysis in patients with hypertensive nephropathy shows that intravenous administration of 20-30 mL of ginkgo leaf extract and dipyridamole injection once daily for 3-4 weeks along with conventional antihypertensive therapy improves levels of 24-hour urinary total protein, serum creatinine, and blood urea nitrogen by 0.6 grams/dL, 33 mg/dL, and 7 mg/dL, respectively (106610). It is unclear if these effects are due to ginkgo, dipyridamole, or the combination.
• Chronic obstructive pulmonary disease (COPD). Oral ginkgo has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Clinical research shows that taking two capsules of a specific combination product (AKL1, AKL International Ltd.) containing ginkgo extract, ginger, and Picrorhiza twice daily for 8 weeks does not improve respiratory symptoms when compared with placebo in patients with COPD (89702).
• Cocaine dependence. It is unclear if oral ginkgo is beneficial for maintenance of abstinence from cocaine. Details: A small clinical trial shows that taking a standardized ginkgo leaf extract called EGb 761 in a dose of 120 mg twice daily for 10 weeks does not help maintain abstinence from cocaine use when compared with placebo in cocaine-dependent patients (87723).
• Cognitive function. It is unclear if oral ginkgo is beneficial for cognitive function. Details: Clinical research in healthy adults shows that taking ginkgo leaf extract daily for up to 12 weeks might improve some measures of cognitive function, such as working and long term memory, attention based tasks, speed of information processing, executive function, immediate and delayed recall, and recognition (6214,6215,8236,8544,8585,8588,9759,16635,87788,87879,95668). Doses used in these studies include single doses of ginkgo extract 240-600 mg (6215,8236), a standardized ginkgo extract called EGb 761, 120-240 mg taken once daily or in 2-3 divided doses daily for 4-24 weeks (5717,6216,8585,8588,87879,95668), or another specific ginkgo extract called LI 1370 (Lichtwer Pharma), 120-300 mg daily in three divided doses for 2 days (6214). However, other clinical studies and one clinical review show no significant effect of ginkgo on gait ability, attention, memory, or executive function regardless of participant age, dose, or formulation used (87907,5718,8586,8587,8588,87907,95667). Due to the small number of study participants, significant differences in baseline cognitive function between groups, and variability in outcome measures, no definitive conclusions can be drawn. Larger scale studies are needed to determine the effect of ginkgo on cognitive function in healthy individuals. There is also conflicting evidence about the effect of ginkgo on cognitive function when taken in combination with other products. Some research suggests that taking ginkgo in combination with Panax ginseng or codonopsis enhances memory in healthy young or middle-aged adults, and the combinations might be more effective than the individual products (8591,9759,87758). These studies have used a specific combination product (Ginkoba M/E, Pharmaton SA) containing ginkgo extract 100-600 mg and Panax ginseng 60-360 mg, taken as a single dose or once daily for 12 weeks (8591,9759) or two capsules of a product containing ginkgo extract 40 mg/capsule and Codonopsis 75 mg/capsule daily (87758). However, other clinical research shows that taking ginkgo combined with Panax ginseng (Gincosan, Pharmaton Natural Health Products) or bacopa extract (Ginkgo Brahmi, Blackmore's Ltd.) for up to 12 weeks does not improve cognition when compared with placebo in healthy adults (87767,87748). Similarly, a moderate-sized clinical study in healthy adults aged 40-65 years shows that taking a supplement containing ginkgo leaf, bacopa, and B vitamins twice daily for 12 weeks does not improve memory or attention when compared with placebo (111334).
• Cognitive impairment. It is unclear if ginkgo is beneficial for cognitive impairment. Details: A clinical study of 500 patients with mild cognitive impairment that is abnormal for their age shows that taking a specific ginkgo standardized extract (EGb761, Tanakan) 40 mg three times daily for 24 months improves scores for cognitive decline, memory, activities of daily living, and depression when compared with baseline (105530). However, it is not clear if these improvements are clinically significant and the validity of the study is limited by the lack of a control group. Cognitive impairment is common side effect of electroconvulsive therapy (ECT). A small clinical study in patients aged 18-60 years with psychiatric disorders undergoing ECT in Iran shows that taking ginkgo (Vitarmonil Co., France) 200 mg after meals, starting 48 hours before initiation of ECT and continuing until the end of ECT sessions, modestly improves scores related to cognitive impairment and memory when compared with placebo (111338). However, it is unclear if these improvements are clinically significant.
• Colorectal cancer. Intravenous ginkgo has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research shows that adding intravenous ginkgo extract (EGb 761 ONC), 350 mg over 30 minutes on days 1-6 of every 3-week cycle to treatment with 5-fluorouracil 500 mg/m2 daily on days 2-6 of every 3-week cycle for 4 courses of treatment, might reduce disease progression in some patients with metastatic colorectal cancer (9872). However, since the study did not include a control group, it is unclear if the effects of treatment were greater than the effects of 5-fluorouracil alone.
• Cough. Although there has been interest in using oral ginkgo for cough, there is insufficient reliable information about the clinical effects of ginkgo for this condition.
• Depression. It is unclear if oral ginkgo is beneficial in depression. Details: Preliminary clinical research in elderly patients shows that taking an unknown dose of a specific ginkgo extract (Harbin HaoBo Pharmaceutical Co., Ltd.) in conjunction with citalopram 20 mg daily for 12 weeks improves depression scores by 75% or more in an additional 3% of patients when compared with taking citalopram alone. Taking ginkgo extract with citalopram also produces a faster onset of action when compared to taking citalopram alone. However, it is not clear if these improvements are clinically significant (98811). A meta-analysis of 21 mainly Chinese studies shows that adding ginkgo preparations in various doses to conventional treatment for depression improves Hamilton Depression Scale scores and increases serotonin levels when compared with conventional treatment alone, but there is high heterogeneity in the results (113779).
• Diabetes. Research on the use of oral ginkgo in type 2 diabetes is conflicting. Details: In patients with uncontrolled type 2 diabetes taking metformin, preliminary clinical research shows that taking ginkgo extract (EGb 761) 120 mg for 90 days reduces glycated hemoglobin (HbA1c) levels from an average of 8.6% at baseline to an average of 7.7%. Fasting serum glucose and insulin were also reduced, when compared with baseline, by approximately 20% and 28%, respectively (103574). However, a meta-analysis of 7 clinical studies shows that taking ginkgo is associated with an increase in HbA1c levels, with no effect on fasting serum glucose levels. The only beneficial effect identified in this analysis was an increase in high density lipoprotein (HDL) cholesterol levels (105529). Another meta-analysis of mainly Chinese studies, shows that adding various ginkgo preparations to metformin for 1-3 years does not improve fasting serum glucose, HbA1c, or cholesterol levels, but does reduce blood viscosity and hematocrit while improving dorsalis pedis artery blood flow and ankle brachial index, suggesting a beneficial effect on peripheral arterial disease associated with diabetes (113780).
• Diabetic retinopathy. It is unclear if oral ginkgo is beneficial for this condition. Details: Preliminary clinical research shows that taking a specific ginkgo leaf extract called EGb 761 120 mg daily orally for 6 months improves measures of color vision when compared with placebo in patients with early diabetic retinopathy (6175).
• Dry eye. Ginkgo eye drops have only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A nonblinded clinical study in adults undergoing cataract surgery and receiving standard treatment shows that applying a specific, preservative-free eye drop (Trium Free; SOOFT) containing ginkgo extract 0.05% and hyaluronic acid 0.15%, three times daily, beginning the first day after surgery and continued for 4 weeks, reduces dry eye severity and symptoms when compared with standard treatment alone. After 4 weeks, 50% of patients in the standard treatment group reported dry eye symptoms, compared with 16% of patients using ginkgo (108609). The effects of ginkgo in patients with chronic dry eye or dry eye caused by other factors is unclear.
• Dyslexia. It is unclear if oral ginkgo is beneficial for dyslexia in children. Details: Preliminary clinical research shows that taking a standardized ginkgo leaf extract (EGb 761) 80 mg daily for an average of 34 days can help reduce dyslexia when compared to baseline in children aged 5-16 years (87790). The validity of this finding is limited by the lack of a comparator group.
• Fibromyalgia. Oral ginkgo has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research shows that taking tablets containing ginkgo extract (Bio-Biloba, Pharma Nord) 200 mg daily in conjunction with capsules containing coenzyme Q10 (Bio Quinone Q10, Pharma Nord) 200 mg daily orally for 84 days improves patient-reported quality of life, such as physical fitness levels, emotional feelings, social activities, overall health, and pain, when compared to baseline (17716). The validity of these findings is limited by the lack of a comparator group.
• Gastric cancer. It is unclear if oral ginkgo is beneficial in gastric cancer. Details: Preliminary clinical research shows that taking carbohydrates from the outer layer of ginkgo fruit 250 mg orally twice daily for 30 days may reduce tumor size in patients with gastric cancer when compared with pre-treatment (87742).
• Glaucoma. It is unclear if oral ginkgo is beneficial in glaucoma. Details: A small observational study has found that taking ginkgo leaf extract 80 mg twice daily for up to 12.3 years is associated with reduced progression of visual field damage in patients with normal tension glaucoma (87900). Furthermore, a small clinical study in patients with normal tension glaucoma shows that taking ginkgo leaf extract 40 mg three times daily for up 4 weeks might improve pre-existing damage and reduce the progression of damage to the visual field (10378). However, conflicting evidence exists. Another small study in patients with newly diagnosed normal tension glaucoma shows that taking a specific ginkgo extract (Ginaton, Dr. Willmar Schwabe Pharmaceuticals) 40 mg three times daily for 4 weeks does not improve damage or progression of glaucoma (89707). Reasons for the discrepancies may be due to the formulation of ginkgo leaf extract used or the severity of glaucoma at baseline.
• Hemorrhoids. Oral ginkgo has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: One small clinical study shows that taking a combination of ginkgo extract, troxerutin, and heptaminol for one week may decrease some symptoms of hemorrhoids, including bleeding, pain, feelings of incomplete defecation, and discharge when compared to baseline (87751). The validity of these findings is limited by the lack of a comparator group. Additionally, it is unclear if these effects are due to ginkgo, other ingredients, or the combination.
• Hypercholesterolemia. Although there has been interest in using oral ginkgo for hypercholesterolemia, there is insufficient reliable information about the clinical effects of ginkgo for this condition.
• Intestinal parasite infection. Although there has been interest in using oral ginkgo for intestinal parasite infection, there is insufficient reliable information about the clinical effects of ginkgo for this condition.
• Lyme disease. Although there has been interest in using oral ginkgo for cognitive dysfunction associated with Lyme disease, there is insufficient reliable information about the clinical effects of ginkgo for this condition.
• Migraine headache. Oral ginkgolide B, a constituent of ginkgo biloba extract, has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research shows that ginkgolide B (BN52021), a constituent of ginkgo extract, along with coenzyme Q10, riboflavin, and magnesium, taken twice daily for 3 months, may help prevent migraines in school-aged children when compared to baseline (44181,87876). Also, a specific product (Migrasoll, Pharmaval Srl) containing ginkgolide B 60 mg, coenzyme Q10 11 mg, and vitamin B2 8.7 mg, taken twice daily for 4 months, may help prevent migraines in females when compared to baseline (44103). The validity of the findings from these studies is limited by the lack of a comparator group.
• Ovarian cancer. It is unclear if oral ginkgo is beneficial in preventing ovarian cancer. Details: Epidemiological evidence found that use of ginkgo extract for 6 months is associated with a decreased risk for developing ovarian cancer (14813).
• Pancreatic cancer. Intravenous ginkgo has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research shows that adding a specific intravenous ginkgo extract called EGb 761 ONC 350 mg on days 1-6 of every 3-week cycle to treatment with 5-fluorouracil 500 mg/m2 daily on days 2-6 of every 3-week cycle until disease progression might slow the progression of pancreatic cancer in some patients (87699). However, since the study did not include a control group, it is unclear if the effects of treatment were greater than the effects of 5-fluorouracil alone.
• Parkinson disease. It is unclear if oral ginkgo is beneficial for drug-induced Parkinsonism. Details: Preliminary clinical research in patients with psychiatric diagnoses treated with antipsychotic drugs shows that taking dried ginkgo extract, 80 mg three times daily orally for 3 months, reduces resting tremors, rigidity, bradykinesia, and the severity of motor symptoms when compared with placebo (112945).
• Peripheral arterial disease (PAD). It is unclear if oral ginkgo is beneficial in PAD. Details: Some small clinical studies show that taking a specific ginkgo leaf extract called EGb 761 (Dr. Willmar Schwabe Pharmaceuticals and Ipsen) orally increases pain-free walking distance in patients with Fontaine's IIb peripheral arterial occlusive disease and intermittent claudication and might decrease overall peripheral vascular disease (PVD) event incidence, such as surgery or amputation, in elderly patients (3461,6211,6212,6213,17402). Significant benefit has been found with doses as low as 120-160 mg daily (6211). However, there is some evidence that a higher dose of 240 mg daily might be more beneficial in some patients (3461,6212). Although some research is positive, other research shows that taking a specific ginkgo leaf extract called EGb 761 (Dr. Willmar Schwabe Pharmaceuticals) 300 mg daily for 16 weeks does not significantly improve maximum treadmill walking time when compared with placebo in patients with PAD (16638). A reason for this discrepancy may be due to the duration of treatment. A meta-analysis of clinical research shows that taking ginkgo leaf extract does not improve maximum treadmill walking distance when compared with placebo in patients with Fontaine stage II PVD and intermittent claudication when administered for 6-8 weeks or 12-16 weeks, but does increase maximum treadmill walking distance by about 85 meters when administered for at least 24 weeks (89440).
• Pulmonary hypertension. It is unclear if intravenous ginkgo is beneficial in patients with pulmonary hypertension and cor pulmonale. Details: A meta-analysis of 28 small, low-quality clinical trials, including nearly 2500 Chinese patients with pulmonary hypertension and cor pulmonale, shows that intravenous administration of ginkgo leaf extract plus dipyridamole 15-40 mL daily for 1-4 weeks along with conventional therapy increases the total effective rate by 28% and improves various blood gas measures when compared with conventional therapy alone (102881). It is unclear if these effects are due to ginkgo, dipyridamole, or the combination. Large, high-quality clinical trials are needed to confirm these results.
• Quality of life. Some preliminary clinical studies suggest that oral ginkgo might improve quality of life in elderly individuals. Details: A large survey-based study shows that taking a standardized ginkgo leaf extract called LI 1370 (Lichtwer Pharma) 120 mg daily for 4-10 months may improve quality of life measures such as activities of daily living, mood, sleep, and alertness in elderly individuals when compared with control (87715,87760).
• Radiation exposure. It is unclear if intravenous ginkgo is beneficial in people who have been exposed to radiation. Details: Preliminary clinical research shows that taking a standardized ginkgo leaf extract called EGb 761 (Tanakan, Ipsen) 120 mg daily for 2 months might reduce clastogenic factors in the blood of patients who had previously been irradiated. The reduction in clastogenic factors was observed for at least 7 months after initiation of ginkgo in most patients (17719).
• Radiation dermatitis. Topical ginkgo has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research shows that applying a specific cream product (Radioskin 2, Herbalab di Perazza Massimiliano Company) containing ginkgo extract, Aloe vera, and metal esculetina, along with another specific cream product (Radioskin 1) containing alga atlantica and ethylbisiminomethylguaicolo manganese cloruro, may improve skin hydration and reduce skin toxicity associated with radiation therapy in patients with breast cancer (89727). The creams were applied topically 2-3 times daily at least 3 hours before and after radiation treatment from 15 days prior to radiation until one month after completion. It is unclear if these effects are due to ginkgo, other ingredients, or the combination.
• Raynaud syndrome. Evidence for the use of oral ginkgo for flare reduction is conflicting. Details: Some research shows that taking a standardized ginkgo extract (Seredrin, Health Perception Ltd.) 120 mg orally three times daily for 10 weeks can decrease the number of painful attacks per week in patients with Raynaud syndrome (11363). However, other research shows that ginkgo extract is no different than placebo in decreasing the number of attacks in these patients (87888). Also, another study shows that taking ginkgo extract 120 mg daily is less effective than nifedipine SR 30 mg daily orally in decreasing Raynaud syndrome flares (87818).
• Scabies. Although there has been interest in using topical ginkgo for scabies, there is insufficient reliable information about the clinical effects of ginkgo for this condition.
• Seasonal affective disorder (SAD). It is unclear if oral ginkgo is beneficial for SAD. Details: One small clinical study shows that taking ginkgo leaf extract orally does not seem to prevent winter depression symptoms in patients with SAD when compared with placebo (8233).
• Sexual dysfunction. It is unclear if oral ginkgo is beneficial for sexual dysfunction in females. Details: Some clinical research shows that taking a ginkgo leaf extract 300 mg daily for 8 weeks does not significantly improve sexual function in females with sexual arousal disorder when compared with placebo (16640). However, other preliminary clinical research shows that taking a specific combination product (ArginMax for Women, Daily Wellness Company) containing ginkgo leaf extract, Panax ginseng root extract, damiana leaf extract, L-arginine, multivitamins, and minerals for 4 weeks can improve sexual satisfaction when compared with placebo in females who self-report sexual dysfunction (46933). It is unclear if these effects are due to ginkgo, other ingredients, or the combination.
• Venous thromboembolism (VTE). Although there has been interest in using oral ginkgo for thrombosis, there is insufficient reliable information about the clinical effects of ginkgo for this condition.
• Vitiligo. It is unclear if oral ginkgo is beneficial for reducing vitiligo progression. Details: Preliminary clinical research shows that taking a specific ginkgo extract (Ginkgo Plus, Seroyal) 120 mg in two divided doses daily for up to 6 months reduces the progression of vitiligo vulgaris and lesion size when compared to baseline (17718,87728). The validity of these findings is limited by the lack of a comparator group.
• Wound healing. Although there has been interest in using topical ginkgo for healing of skin sores or chilblains, there is insufficient reliable information about the clinical effects of ginkgo for these conditions. More evidence is needed to rate ginkgo for these uses.

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POSSIBLY EFFECTIVE

• Age-related cognitive decline. Oral bovine cortex-derived phosphatidylserine seems to improve attention and memory in patients with age-related cognitive decline. It is unclear if plant-derived phosphatidylserine is beneficial or whether phosphatidylserine is beneficial for preventing cognitive decline. Details: Clinical studies in people with age-related cognitive decline show that phosphatidylserine improves attention, arousal, verbal fluency, and memory (2440,2441,7119,7120,15539). Bovine- and plant-sourced phosphatidylserine 100 mg three times daily for up to 6 months has been used in these studies (2440,2441,15539). Most clinical studies have used phosphatidylserine derived from bovine cortex. However, most supplements now use soy- or cabbage-derived phosphatidylserine. There is some preliminary evidence that plant-derived phosphatidylserine also improves memory in people with age-associated memory impairment (15539). Also, clinical research in elderly females with complaints of memory loss shows that taking 1-3 capsules of a specific product (Vayacog, Enzymotec Ltd.) containing soybean-derived phosphatidylserine 100 mg/capsule, enriched with docosahexaenoic acid (DHA) 19.5 mg/capsule and eicosapentaenoic acid (EPA) 6.5 mg/capsule, daily for 15 weeks modestly improves immediate memory and sustained attention when compared with placebo (66055,90711). A post-hoc analysis of the results from this study suggests that cognitive improvements are greatest in patients with relatively good cognitive performance at baseline (66055). There is also interest in using phosphatidylserine to prevent age-related cognitive decline. In 2003, the US Food and Drug Administration (FDA) determined that it would allow a qualified health claim stating that consuming phosphatidylserine may reduce the risk of developing age-related cognitive decline. However, the FDA has determined that there is very little scientific evidence supporting this claim (102363).
• Alzheimer disease. Oral bovine cortex-derived phosphatidylserine seems to improve cognitive function and behavior in patients with Alzheimer disease when used for up to 12 weeks, although benefits may disappear after 16 weeks. It is unclear if plant-derived phosphatidylserine is beneficial. Details: Taking phosphatidylserine orally can improve cognitive function and global improvement rating scales and improve behavioral rating scales over 6-12 weeks of treatment (2255,2437,2438,2439,7114,7118). Bovine-sourced phosphatidylserine 300-400 mg in divided doses daily for up to 16 weeks has been used (2255,2437,2438,2439). Phosphatidylserine seems to be most effective in patients with less severe symptoms (2437,2439). Phosphatidylserine might lose its effectiveness with extended use. After 16 weeks of treatment, progression of Alzheimer disease seems to overcome any benefit of phosphatidylserine (2255). Most clinical studies have used phosphatidylserine derived from bovine cortex. However, most supplements now use soy- or cabbage-derived phosphatidylserine. Clinical studies have not yet evaluated phosphatidylserine from soy or other sources. It is not known if phosphatidylserine from these sources is as effective as bovine-derived products.

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Athletic performance. It is unclear if oral phosphatidylserine is beneficial for athletic performance. Details: One small clinical trial in golfers shows that taking nutritional bars containing phosphatidylserine 200 mg daily for 6 weeks improves the number of good ball flights, which may improve golf score; however, perceived stress levels and heart rate are not significantly affected (68855). A clinical study in recreationally active adults shows that taking phosphatidylserine 400 mg and caffeine 100 mg daily, along with niacin 28 mg, vitamin C 60 mg, vitamin B1 1.5 mg, vitamin B5 10 mg, vitamin B6 2 mg, vitamin E 12 IU, calcium 100 mg, magnesium 40 mg, and carbohydrates in the form of evaporated cane juice, brown rice syrup, and rice syrup solids 16 grams (Nutravail Technologies) for 14 days modestly reduces post-exercise mood disturbances and perception of fatigue when compared with vitamins and minerals alone. The combination does not appear to improve cognitive function or reaction time (91463). It is not clear if the effect of the combination supplement is due to phosphatidylserine, caffeine, or the combination.
• Attention deficit-hyperactivity disorder (ADHD). It is unclear if oral phosphatidylserine is beneficial for ADHD. Details: A meta-analysis of three generally low-quality randomized clinical trials shows that taking phosphatidylserine 200-300 mg daily for 8-15 weeks modestly improves symptoms of inattention in children with ADHD when compared with placebo. However, there were no significant effects on hyperactivity-impulsivity or on overall ADHD symptoms. Also, two of the three clinical trials included in the analysis investigated the effects of phosphatidylserine in combination with the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) (105247). One preliminary clinical trial included in the analysis shows that taking soy-derived phosphatidylserine 200 mg daily for 2 months improves ADHD symptoms, including inattention, hyperactivity-impulsivity, and short-term memory, when compared to baseline in treatment-naïve children with ADHD aged 4-14 years. However, results from this study are limited due to a lack of statistical comparison to the placebo group (89498).
• Cognitive function. Although there is interest in using oral phosphatidylserine for improving cognitive function in healthy adults, there is insufficient reliable information about the clinical effects of phosphatidylserine for this purpose.
• Dementia. It is unclear if oral phosphatidylserine is beneficial for dementia prevention or treatment. Details: In 2003, the FDA determined that it would allow a qualified health claim stating that consuming phosphatidylserine may reduce the risk of dementia in the elderly. However, the FDA has determined that there is very little scientific evidence supporting this claim (102363).
• Depression. It is unclear if oral phosphatidylserine is beneficial for depression. Details: One very small clinical study in elderly adults with depression shows that taking phosphatidylserine 300 mg daily for 30 days modestly improves depression scores when compared to baseline (7113).
• Exercise-induced muscle soreness. It is unclear if oral phosphatidylserine is beneficial for exercise-induced muscle soreness. Details: One small clinical study in athletes shows that taking soybean-derived phosphatidylserine 800 mg daily for 2 weeks during periods of over-training reduces muscle soreness post-exercise when compared with those not taking phosphatidylserine (2264). More evidence is needed to rate phosphatidylserine for these uses.

(Read more about PHOSPHATIDYLSERINE)

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

• Imerslund-Grasbeck disease. Intramuscular vitamin B12 is effective for patients with this condition. Details: Administering intramuscular vitamin B12 (hydroxocobalamin) 1 mg daily for 10 days, followed by monthly injections for the remainder of a patient's life, is effective for treating familial selective vitamin B12 malabsorption (Imerslund-Grasbeck disease) (15,82862).
• Vitamin B12 deficiency. Administering vitamin B12 orally, intramuscularly, or intranasally is effective for preventing and treating vitamin B12 deficiency. Details: Vitamin B12 deficiency has varying definitions but is often defined as vitamin B12 (cobalamin) levels less than 180-200 pmol/L (or 240 pg/mL). Some believe that only intramuscular vitamin B12 is effective for treating vitamin B12 deficiency. However, clinical research shows that oral therapy increases cobalamin levels similarly to intramuscular administration, even in patients with pernicious anemia or malabsorption, if a high enough dose is given (2909,2911,2915,9335,82832) (82836,82949,82860,103976,103972,107141,107144). Some evidence suggests that the most effective oral dose is between 647-1032 mcg daily (13106). However, in certain situations, intramuscular treatment might be more appropriate. Guidelines by the British Committee for Standards in Hematology recommend only intramuscular vitamin B12 for initial treatment of severe vitamin B12 deficiency in patients with pernicious anemia, malabsorption disorders, or neurological involvement (94722). Intramuscular vitamin B12 is also appropriate in patients with diarrhea or vomiting and those likely to be nonadherent (103972). Vitamin B12 deficiency is especially common in older adults, primarily due to lack of intrinsic factor and malabsorption (2915,2919,9335). Daily supplementation with vitamin B12 50-100 mcg might be needed to correct deficiency (10126), while daily doses of 25-37.5 mcg help to maintain normal levels over time (9335). In addition to supplements, foods such as milk and bread fortified with vitamin B12 can be used and are approximately 55% to 60% absorbed by people over 60 years of age (10124). Vitamin B12 deficiency is also common in patients that have had gastric surgery, including gastrectomy and bariatric surgery (107144,107145). Taking vitamin B12 in the doses found in multivitamins or generic vitamin B supplements does not seem to prevent vitamin B12 deficiency following bariatric surgery (107145). However, taking methylcobalamin 500 mcg daily is beneficial for treating vitamin B12 deficiency associated with a total gastrectomy and taking cyanocobalamin 5000 mcg daily is beneficial for preventing vitamin B12 deficiency following gastric bypass (107144). Other people at risk for vitamin B12 deficiency include strict vegetarians who eat no animal products (vegans) and people with increased vitamin B12 requirements associated with pregnancy, thyrotoxicosis, hemolytic anemia, hemorrhage, malignancy, and hepatic and kidney disease. Moderate consumption of animal products may not be sufficient to restore and maintain vitamin B12 levels, especially in adolescents who had consumed macrobiotic (vegan type) diets for the first 6 years of life. High dietary intake of vitamin B12 or supplements is usually needed in order to restore and maintain optimal vitamin B12 levels in these adolescents (10125).

LIKELY EFFECTIVE

• Cyanide poisoning. Intravenous hydroxocobalamin (Cyanokit) is likely effective as an antidote for patients with suspected or known cyanide toxicity due to inhalation, ingestion, or skin exposure. Details: Treatment of cyanide poisoning with hydroxocobalamin (Cyanokit) up to 10 grams has been approved by the US Food and Drug Administration (FDA) and recommended by the Australian Resuscitation Council (82870,82905,82906). Hydroxocobalamin is also FDA-approved for treating cyanide toxicity during pregnancy (82904).

POSSIBLY EFFECTIVE

• Canker sores. Sublingual or topical vitamin B12 seems to reduce canker sore symptoms. Details: Clinical research in patients with canker sores shows that applying a topical ointment containing vitamin B12 500 mcg in four divided doses daily for 2 days reduces pain levels by 80% when compared with a control ointment not containing vitamin B12 (96176). Other preliminary clinical research shows that taking vitamin B12 1000 mcg sublingually daily for 6 months reduces the duration of canker sore outbreaks, the number of ulcers, and level of pain when compared with placebo in patients with normal vitamin B12 levels (17242).
• Hyperhomocysteinemia. Oral vitamin B12 in combination with folic acid, and sometimes with vitamin B6, reduces homocysteine levels. Details: While folic acid 0.5-5 mg daily lowers fasting homocysteine levels by an average of 25%, adding vitamin B12 0.5 mg daily produces an additional decrease of about 7% on average (6883,9400,9401,9405,9409,50145,107136). Vitamin B12 in combination with folic acid and other vitamins also reduces homocysteine levels in patients with kidney failure, sickle cell disease, and those receiving nitrous oxide general anesthesia (1489,6883,6884,7289,7881,9324,9414,9415,9416,9481,82941). Some researchers recommend routine use of vitamin B12 with homocysteine-lowering regimens to avoid the risk of neuropathy in people with undetected vitamin B12 deficiency (9405). Using vitamin B12 alone has a limited effect on homocysteine levels, and probably only in those people with vitamin B12 deficiency (2147,9410,9512). Hyperhomocysteinemia is considered by some to be an independent risk factor for atherosclerosis, recurrent thromboembolism, deep vein thrombosis, myocardial infarction, and ischemic stroke (1899,2147,3323,9402,9405,9408,9409). Clinical research suggests that supplementation with folic acid, pyridoxine, and vitamin B12 decreases homocysteine levels and reduces the atherosclerosis progression in patients at risk for atherosclerosis when compared with placebo (50133,50056,82806). However, other research suggests that elevated homocysteine levels may be a marker, as opposed to a cause, of vascular disease (11387,11388). A 5 µmol/L increase in plasma homocysteine increases the risk of cerebrovascular disease by 50%, and the odds of coronary heart disease by 60% and 80% in males and females, respectively (9407,9411). However, it is not clear if reducing homocysteine levels results in reduced cardiovascular morbidity and mortality (1489,6883,6884,9400,9405,9409,96417). Folic acid, vitamin B6, and vitamin B12 supplementation can reduce total homocysteine from 13.4 to 11 µmol/L. However, this reduction does not seem improve endothelial function or help with secondary prevention of death or myocardial infarction, and some research even suggests an increase in cardiovascular disease (CVD) risk (11387,13482,50373,50314,97619). There is also some debate about whether supplementation with homocysteine-lowering B vitamins can reduce the risk of stroke. A number of large clinical studies and meta-analyses show that supplementation with folic acid, vitamin B6, and vitamin B12, alone or in combination, does not reduce the risk of stroke in patients with CVD or impaired kidney function (11387,13482,50423,83050,96150). However, a more recent meta-analysis of 10 clinical trials including over 44,000 patients shows that B vitamin supplementation reduces the relative risk of stroke by 10% when compared with placebo in patients at risk or with a history of CVD (97619). Also, a meta-analysis in adults with a history of stroke shows that B vitamin supplementation modestly reduces the relative risk of stroke recurrence by 13% and vascular death by 11% when compared with placebo (107136).
• Postherpetic neuralgia. Subcutaneous injections of vitamin B12 seem to reduce postherpetic neuralgia symptoms. Details: Clinical research in patients with subacute herpetic neuralgia shows that subcutaneous injection of vitamin B12 (methylcobalamin) 1000 mcg six times weekly for 4 weeks reduces pain when compared with oral vitamin B12 or subcutaneous lidocaine (90394). Another clinical study shows that administering local subcutaneous injections of methylcobalamin 1000 mcg plus lidocaine up to 20 mg daily for 12 injections over 14 days, starting within 7 days of the onset of subacute ophthalmic herpetic neuralgia, decreases the mean pain score by 63% to 79% when compared with intravenous lidocaine and intramuscular methylcobalamin. Less than 2 patients need to be treated to achieve a pain reduction to ≤3 out of 10. Healing of rash, itching, numbness, and tingling were also improved (96175). Additional clinical research in patients with postherpetic pain and itching shows that this same dosing regimen of subcutaneous vitamin B12 reduces pain and analgesic requirements when compared to baseline (90396).

POSSIBLY INEFFECTIVE

• Age-related cognitive decline. Oral vitamin B12 does not seem to improve cognitive function in older adults when used alone or in combination with other B vitamins. Details: Taking vitamin B12 100-1000 mcg plus folic acid 400-2000 mcg, with or without vitamin B6 3-50 mg, daily for up to about 2 years does not seem to improve tests of cognitive function in adults aged 65 or older, most of whom do not report cognitive impairment at baseline (14392,50225,50510,90392,107140). Also, supplementation with vitamin B12 does not seem to improve cognitive function in elderly individuals with low vitamin B12 levels (12305).
• Alzheimer disease. Oral vitamin B12, when used in combination with other B vitamins, does not seem to improve cognitive function in patients with Alzheimer disease. Details: Clinical research in patients with probable Alzheimer disease using routine medication shows that taking vitamin B12 1 mg, folic acid 5 mg, and vitamin B6 25 mg daily for 18 months does not have a beneficial effect on cognitive function or the severity of disease when compared with placebo. In this study, all patients were consuming a folate-fortified diet (50319). Also, a meta-analysis of clinical research in elderly adults with mild cognitive impairment or dementia shows that taking vitamin B12, usually with other B vitamins, does not improve cognitive function (50510). Observational research has also found that higher vitamin B12 intake over 3 years in a population consuming a folate-fortified diet is not associated with a decreased risk of developing Alzheimer disease (15270). In contrast, preliminary clinical research in patients with probable Alzheimer disease who are not consuming a folate-fortified diet shows that taking vitamin B12 50 mcg daily plus folic acid 1.2 mg daily for 6 months modestly improves some measures of cognitive performance and decreases levels of homocysteine when compared with placebo (107150). More research is needed to determine if any changes in this latter study are clinically relevant.
• Cataracts. Oral vitamin B12 does not seem to reduce cataract development. Details: Clinical research in women with existing cardiovascular disease (CVD) or at increased risk of CVD shows that taking a combination of folic acid 2.5 mg daily, vitamin B6 50 mg daily, and vitamin B12 1 mg daily for an average of 7.3 years does not reduce the risk of cataracts and seems to increase the risk of cataract extraction by 28% when compared with placebo (96149).
• Circadian rhythm sleep disorders. Oral vitamin B12 does not seem to improve sleep disorders. Details: Oral vitamin B12 (methylcobalamin) does not seem to be effective for treating delayed sleep phase syndrome. Methylcobalamin 0.5-1 mg three times daily, with or without bright light therapy, also does not seem to help people with primary circadian rhythm sleep disorders (1344,1345,1346,1347,1348).
• Cognitive impairment. Oral vitamin B12 does not seem to be beneficial for older adults with cognitive impairment. Details: A meta-analysis of clinical research in elderly adults with mild cognitive impairment or dementia shows that taking vitamin B12, usually with other B vitamins, does not improve cognitive function (50510). One clinical trial in elderly people with memory complaints shows that taking a combination of B vitamins, including folic acid 0.8 mg, vitamin B12 0.5 mg, and vitamin B6 (form not specified) 20 mg daily for 24 months reduces cerebral atrophy in the gray matter regions associated with Alzheimer disease by up to seven-fold when compared with placebo. However, this protection does not occur in patients with the lowest average blood levels of homocysteine (90374).
• Fall prevention. Oral vitamin B12 does not seem to reduce the risk of falls. Details: Clinical research shows that taking B vitamins, including folic acid 400 mcg and vitamin B12 500 mcg, daily for 2 years does not prevent falls when compared with placebo in elderly individuals also taking vitamin D (96148).
• Osteoporosis. Oral vitamin B12 does not seem to reduce the risk of osteoporotic fractures. Details: Clinical research in elderly patients or patients with a history of cerebrovascular disease shows that taking vitamin B12 500 mcg and folic acid 0.4-2 mg, with or without vitamin B6 25 mg, daily for 2-3 years does not seem to reduce the risk for osteoporotic fractures when compared with placebo (90377,90393). A 5-7 year follow-up of this research has also found no benefit (103981).
• Physical performance. Oral vitamin B12 does not seem to improve physical performance in older adults. Details: Clinical research shows that taking B vitamins, including folic acid 400 mcg and vitamin B12 500 mcg, daily for 2 years does not increase hand strength or improve performance such as walking when compared with placebo in elderly individuals also taking vitamin D (96148).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Age-related macular degeneration (AMD). Oral vitamin B12 has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A large-scale clinical study shows that taking vitamin B12 1000 mcg, folic acid 2.5 mg, and vitamin B6 50 mg daily, reduces the risk of developing AMD in females over 40 years of age with a history of cardiovascular disease (CVD) or at least three risk factors for CVD. Those who took this combination for an average of 7.3 years had a 34% reduced risk of developing AMD and a 41% reduced risk of visually significant AMD when compared with placebo (14620). It is unclear if this effect is due to vitamin B12, other ingredients, or the combination.
• Amyotrophic lateral sclerosis (ALS, Lou Gehrig's disease). It is unclear if high-dose intramuscular vitamin B12 improves the prognosis of ALS. Details: A clinical study in patients with ALS symptoms for 3 years or less shows that intramuscular vitamin B12 (methylcobalamin) 25-50 mg twice weekly for 3.5 years does not slow functional decline or increase the time until ventilation or death when compared with placebo. However, other clinical research in patients with early-stage ALS shows that intramuscular methylcobalamin 50 mg twice weekly for 16 weeks is associated with slower functional decline and a longer period of time until death or full ventilation when compared with placebo (104947,111556). These effects seem to be particularly notable in fine and gross motor skills, but not bulbar or respiratory functions. Furthermore, vitamin B12 and riluzole slowed clinical progression of ALS more than riluzole alone (111556).
• Angioplasty. Oral vitamin B12 has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Some evidence suggests that vitamin B12 400 mcg, folic acid 1 mg, and vitamin B6 10 mg daily can decrease the rate of restenosis in patients treated with balloon angioplasty (8009,9412,34540). However, this combination does not seem to be as effective for reducing restenosis in patients after coronary stenting (8009). An intravenous loading dose of folic acid, pyridoxine, and vitamin B12 followed by oral administration of folic acid 1.2 mg, pyridoxine 48 mg, and vitamin B12 60 mcg daily after bare metal coronary stenting also does not seem to reduce restenosis and might actually increase restenosis (12150,12151,34540). Due to the lack of evidence of benefit and potential for harm, this combination of vitamins should not be recommended for patients receiving coronary stents (12151). It is unclear if any effects are due to vitamin B12, other ingredients, or the combination.
• Anxiety. Although there is interest in using oral vitamin B12 for anxiety and panic attacks, there is insufficient reliable information about the clinical effects of vitamin B12 for these uses.
• Asthma. Although there is interest in using oral vitamin B12 for asthma, there is insufficient reliable information about the clinical effects of vitamin B12 for this condition.
• Atherosclerosis. Oral vitamin B12 has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: One small clinical study in patients with intermediate risk for coronary heart disease shows that taking vitamin B12 100 mcg, aged garlic extract 250 mg, folic acid 300 mcg, vitamin B6 12.5 mg, and L-arginine 100 mg daily for 12 months reduces coronary artery calcium progression when compared with placebo (88385). It is unclear if this effect is due to vitamin B12, other ingredients, or the combination.
• Atopic dermatitis (eczema). It is unclear if topical vitamin B12 reduces the severity of eczema. Details: Preliminary clinical research shows that applying a specific topical vitamin B12 0.07% cream (Regividerm) twice daily reduces the extent and severity of atopic dermatitis when compared with placebo (15765).
• Attention. Although there is interest in using oral vitamin B12 for improving attention and focus, there is insufficient reliable information about the clinical effects of vitamin B12 for this use.
• Cancer. It is unclear if oral vitamin B12 reduces overall cancer risk when used in combination with other B vitamins. Details: An ancillary clinical study in middle-aged and elderly adults with cardiovascular disease shows that taking a combination of vitamin B12 (cyanocobalamin) 0.02 mg, folic acid 0.56 mg, and vitamin B6 3 mg, with or without eicosapentaenoic acid (EPA) 400 mg plus docosahexaenoic acid (DHA) 200 mg, for a median of 4.7 years does not reduce the risk of cancer when compared with placebo (90666). An additional secondary analysis of clinical research in patients recovering from stroke or transient ischemic attack shows that taking vitamin B12 500 mcg, folic acid 2 mg, and vitamin B6 25 mg daily for around 3.4 years does not reduce the risk of cancer when compared with placebo (90378). The validity of these findings is limited because the studies were not designed nor adequately powered to test for cancer risk.
• Cardiovascular disease (CVD). Oral vitamin B12, taken along with other B vitamins, does not seem to improve secondary prevention of death or myocardial infarction in patients with CVD. However, it might slightly reduce the risk of stroke. Details: Overall evidence from clinical research and meta-analyses shows that taking vitamin B12 in combination with folic acid and/or vitamin B6 does not seem to reduce the risk for secondary death or myocardial infarction in patients with or at risk for CVD (11387,13482,34540,50423,83050,90379,97619). In fact, some research suggests that long-term supplementation with vitamin B6, folic acid, and vitamin B12 for secondary prevention increases the risk of CVD by 20% despite lowering homocysteine levels by 30% (13482). However, other research shows that taking vitamin B12 in combination with other B vitamins modestly reduces the risk of stroke, although results are conflicting (11387,13482,50423,83050,96150,96165,97619,107136). It is unclear which specific combination of B vitamins, if any, might be optimal for reducing stroke risk and which patients are most likely to benefit. In 2001, prior to the publication of the highest quality research on this topic, the US Food and Drug Administration (FDA) approved a qualified health claim stating that, as part of a well-balanced diet that is low in saturated fat and cholesterol, folic acid, vitamin B6, and vitamin B12 may reduce the risk of vascular disease (102368).
• Cervical cancer. It is unclear if oral vitamin B12 reduces cervical cancer risk. Details: Some epidemiological evidence has found that increasing vitamin B12 intake from dietary and supplement sources, along with folic acid, thiamine, and riboflavin, might decrease the risk of precancerous cervical lesions (11074). Also, an analysis of two case control studies has found that increased intake of vitamin B12 is associated with a 75% reduced odds of cervical cancer (34609).
• Chemotherapy-induced peripheral neuropathy. Oral vitamin B12 has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in patients receiving chemotherapy shows that a combination of B vitamins that includes vitamin B12 (cyanocobalamin) 1000 mcg, taken daily starting one week prior to treatment and finishing 12 weeks after treatment is completed, does not prevent peripheral neuropathy when compared with placebo (96173).
• Child development. It is unclear if oral vitamin B12 is beneficial for child development. Details: Population research has found that daily dietary intake of less than 2.26 mcg vitamin B12 in the third trimester of pregnancy is associated with an increased risk of poorer outcomes in the offspring for some measures of speech and mathematics ability, including vocabulary at 24 months, combining words at 38 months, speech intelligibility at 6 years, and math comprehension between ages 8-11 years, when compared with dietary intakes of at least 2.26 mcg daily. There was no association between prenatal vitamin B12 intake and reading or spelling abilities, vocabulary at other ages, or full-scale Intelligence Quotient (IQ) at ages 8 or 15 (107143). Furthermore, a very large clinical study in infants of pregnant adults, 71% of whom were deficient in vitamin B12 at baseline, shows that taking vitamin B12 50 mcg daily starting in early pregnancy (<15 weeks gestation) until 6 months postpartum does not improve neurodevelopment as measured by language, motor, socioemotional, or cognitive scores at 12 months old and may worsen early motor performance at 8-12 weeks when compared with placebo. However, the negative effects on motor performance resolved by 6 and 12 months of age (112431).
• Child growth. Oral vitamin B12 taken by pregnant adults does not seem to be beneficial for infant growth. Details: A very large clinical study in infants of pregnant adults, 71% of whom were deficient in vitamin B12 at baseline, shows that taking vitamin B12 50 mcg daily starting in early pregnancy (<15 weeks gestation) until 6 months postpartum does not improve the infant's linear growth, length, or weight at 12 months of age (112431).
• Chronic obstructive pulmonary disease (COPD). It is unclear if oral vitamin B12 reduces the risk of COPD. Details: Clinical research in patients with COPD shows that taking vitamin B12 500 mg daily for 8 weeks modestly improves endurance on the cycle ergometer, but does not improve oxygen consumption, when compared with placebo (96172).
• Cognitive function. Oral vitamin B12 has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A moderate-sized clinical study in healthy, middle-aged adults shows that taking a combination product containing vitamin B12, other B vitamins, bacopa, and gingko biloba twice daily for 12 weeks does not improve measures of memory, attention, cognition, mood, or stress reactivity when compared with placebo (111334).
• Colorectal cancer. It is unclear if oral vitamin B12 reduces colorectal cancer risk. Details: Some epidemiological evidence has found that increased dietary intake of vitamin B12 is associated with a reduced risk of developing colorectal cancer (90383). However, preliminary clinical research shows that taking vitamin B12 1 mg, folic acid 2.5 mg, and vitamin B6 50 mg daily for up to 7.3 years does not reduce the risk of colorectal adenoma in females at high risk for cardiovascular disease (90389). Furthermore, a secondary analysis of clinical research in elderly patients suggests that taking vitamin B12 500 mcg and folic acid 400 mcg daily for 2 years might increase the risk of colorectal cancer when compared with placebo (90393).
• Coronavirus disease 2019 (COVID-19). It is unclear if oral vitamin B12 is beneficial for patients with COVID-19. Details: A small observational study in hospitalized patients with COVID-19 pneumonia has found that higher plasma vitamin B12 levels may be associated with an increased risk of transfer to intensive care or death than lower plasma levels. However, when multivariate regression was conducted, only patient age was associated with worsened outcomes. Additionally, the total study population was small, with only nine of 49 patients experiencing the worsened outcomes (107138).
• Dementia. It is unclear if oral vitamin B12 reduces the risk of developing dementia. Details: A large cohort of Danish adults has found that vitamin B12 levels or intake does not seem to impact the risk of developing Alzheimer disease or other dementias (104922). However, vitamin B12 might be beneficial in specific patient populations. A small observational study in patients with Parkinson disease has found that higher vitamin B12 levels (648.5 ng/L) are associated with a lower risk of developing dementia when compared with lower vitamin B12 levels (452 ng/L) (103975). It is not yet known if supplementation with vitamin B12 reduces the risk for dementia in these patients.
• Depression. It is unclear if oral vitamin B12 is beneficial for reducing depression risk. Details: A meta-analysis of epidemiological research has found that the highest dietary intake of vitamin B12 is associated with a 14% reduced risk of depression. However, in a sub-analysis, this association was not significant in males (107133). In contrast, one epidemiological study in older males included in the analysis has found that daily dietary intake of at least 4.79 mcg vitamin B12 is linked with a 58% lower risk of depression when compared with daily intake of less than 3.16 mcg. In this study, this inverse association was not observed in females (96168). Other observational research has found that low-normal serum vitamin B12 levels are associated with a 3.8 times increased risk for depression during pregnancy when compared with normal vitamin B12 levels (102384). It is unclear if increased intake of vitamin B12 through the diet or supplements reduces the risk for depression or is beneficial for treating symptoms of depression in any population. However, a meta-analysis of clinical research in elderly populations shows that supplementation with vitamin B12 100-1000 mcg daily, usually in combination with folic acid 400-2000 mcg daily, does not reduce symptoms of depression. Most individuals in these studies were not specifically diagnosed with depression (107140).
• Diabetes. It is unclear if oral vitamin B12 improves glycemic indices or prevents loss of skeletal muscle in patients with diabetes. Details: A small clinical study in patients with diabetes in India who are stabilized on metformin and/or a sulfonylurea shows that taking vitamin B12 (methylcobalamin) 500 mcg with or without folic acid 5 mg daily for 8 weeks seems to reduce glycated hemoglobin (HbA1C) by 1.3% to 1.5%, compared with a 0.3% increase with placebo (104917). This study is limited due its small sample size and lack of blinding. In elderly adults with type 2 diabetes, population research has found a lower dietary intake of vitamin B12 (average of 11.2 mcg daily) in individuals with a loss of skeletal muscle mass of at least 1.2%, compared with an average intake of 13.4 mcg daily in those with a skeletal muscle mass loss of less than 1.2%. However, further analysis determined that any relationship between vitamin B12 intake and loss of skeletal muscle mass was only significant in individuals with insufficient energy intake overall (107151).
• Diabetic neuropathy. Small clinical studies suggest that oral vitamin B12 may modestly improve pain in patients with diabetic neuropathy. Details: Two small clinical studies in patients with diabetic peripheral neuropathy show that taking vitamin B12 (methylcobalamin) 1-1.5 mg for 4-12 months modestly improves pain when compared with baseline or placebo (82841,104923). Some research also shows that vitamin B12 may be beneficial in combination with other ingredients. Studies have evaluated products containing vitamin B12 (methylcobalamin or cyanocobalamin), benfotiamine, and vitamin B6 daily for 9-12 weeks (82931,82939); and vitamin B12 (methylcobalamin) 2 mg, folic acid (L-methylfolate) 3 mg, and vitamin B6 (pyridoxal-5'-phosphate) 35 mg (Metanx; Pamlab) daily for 24 weeks (90375).
• Diarrhea. It is unclear if oral vitamin B12 is beneficial for reducing diarrhea in children. Details: Preliminary clinical research in children aged 6-30 months from low- and middle-income countries shows that taking vitamin B12 at twice the recommended dietary allowance, with or without folic acid, does not reduce the risk for diarrhea when compared with placebo (90391).
• Fatigue. It is unclear if intramuscular vitamin B12 is beneficial for improving well-being in those with fatigue or tiredness. Details: A small crossover trial in patients complaining of tiredness or fatigue shows that receiving intramuscular injections of vitamin B12 (hydroxocobalamin) 5 mg twice weekly for 2 weeks seems to improve general well-being and happiness, and has a trend toward improving fatigue, when compared with placebo (10127). The validity of this study is limited by a large drop-out rate and unstandardized outcome measures.
• Hearing loss. Oral vitamin B12 has only been evaluated in combination with adenosine triphosphate; its effect when used alone is unclear. Details: A small observational study in adults with idiopathic sudden sensorineural hearing loss has found that taking vitamin B12 1.5 mg with adenosine triphosphate 300 mg daily for 8-16 weeks is associated with modestly reduced hearing loss at 4-6 months after starting treatment when compared with taking the combination for less than 8 weeks (104924). This finding is limited due to its observational nature and lack of a control group.
• Hepatitis C. It is unclear if intramuscular vitamin B12 is beneficial for sustaining viral response in patients with chronic hepatitis C infection. Details: A small clinical study in patients with chronic hepatitis C infection shows that intramuscular vitamin B12 (cyanocobalamin) 5000 mcg every 4 weeks along with standard care improves sustained viral response when compared with standard of care alone (90386).
• Hypertriglyceridemia. It is unclear if oral vitamin B12 is beneficial for reducing triglyceride levels. Details: Some evidence shows that taking vitamin B12 7.5 mcg with fish oil 5 grams might be superior to fish oil alone when used daily to reduce total serum cholesterol and triglycerides. This suggests vitamin B12 might have an independent effect in lowering serum cholesterol and triglycerides, but further investigation is needed to confirm this effect (8694).
• Hypotension. It is unclear if oral vitamin B12 is beneficial for treating hypotension. Details: A meta-analysis of 3 observational studies in patients hospitalized with hypotension secondary to cardiac surgery vasoplegia suggests that administration of intravenous vitamin B12 (hydroxocobalamin) is associated with an 8 mmHg higher mean arterial pressure (MAP) at 1 hour but no change in vasopressor dosage at 1 hour or mortality rate when compared with methylene blue (112264). The validity of these findings is limited by the inclusion of only retrospective studies.
• Infant development. It is unclear if taking oral vitamin B12 during pregnancy is beneficial for improving infant development. Giving oral vitamin B12 to infants does not seem to be beneficial. Details: Clinical research shows that supplementation with vitamin B12 50 mcg daily from less than 14 weeks gestation until 6 weeks postpartum does not improve cognitive development in infants by 9 months of age when compared with placebo (96174). When these children were evaluated at 30 months of age, a very small benefit of vitamin B12 on expressive language was identified; however, there was no effect on cognition, receptive language, fine motor skills, or gross motor skills (100169). It is unknown whether a longer duration of postpartum supplementation or supplementation in specific populations might be beneficial. Vitamin B12 supplementation in infants has also been evaluated. A large clinical trial in marginally stunted Nepalese infants aged 6-11 months shows that giving vitamin B12 (cyanocobalamin) 2 mcg daily for 12 months reduces homocysteine levels, but does not improve motor or cognitive development, when compared with placebo (104926).
• Inflammatory bowel disease (IBD). Although there is interest in using oral vitamin B12 for IBD, there is insufficient reliable information about the clinical effects of vitamin B12 for this condition.
• Lung cancer. Oral vitamin B12 has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: The association between vitamin B12 and lung cancer is unclear. Some population research found no relationship between blood levels of vitamin B12 and lung cancer (9454). However, other observational research involving over 5,000 case-control pairs found that higher vitamin B12 levels are linked with an increased risk for lung cancer (102383). It is unclear if increased intake of vitamin B12, either through the diet or supplementation, directly affects the risk of lung cancer.
• Male infertility. Oral vitamin B12 has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A retrospective study in adult males with idiopathic and varicocele-related infertility suggests that taking a combination product containing vitamin B12 1.5 mcg, L-carnitine, acetyl L-carnitine, citric acid, selenium, coenzyme Q10, vitamin C, zinc, and folic acid (Proxeed Plus) twice daily for 6 months is associated with improvements in ejaculate volume, sperm count, sperm concentration, total motility, and progressive motility in patients with idiopathic infertility when compared to baseline. However, improvement in sperm morphology was lacking. Furthermore, patients with more severe varicocele seem to benefit most, especially with regard to progressive motility (111296). The validity of these findings is limited by a lack of comparator group. Further, it is unclear if these effects are due to vitamin B12, other ingredients, or the combination.
• Mastalgia. Oral vitamin B12 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 B12 as methylcobalamin 100 mg, gamma-linolenic acid, and vitamin C daily for 12 weeks does not improve the proportion of patients with minimal or no pain when compared with placebo (111059).
• Multiple sclerosis (MS). Although there is interest in using oral vitamin B12 for MS, there is insufficient reliable information about the clinical effects of vitamin B12 for this condition.
• Nonalcoholic fatty liver disease (NAFLD). It is unclear if oral vitamin B12 is beneficial for NAFLD. Details: A small clinical study in adults with NAFLD shows that taking vitamin B12 1000 mcg daily for 12 weeks reduces serum levels of homocysteine but has no effect on serum aminotransferases, measures of steatosis, fibrosis scores, fasting blood glucose, serum insulin, measures of insulin resistance, triglycerides, low-density lipoprotein (LDL) cholesterol, or high-density lipoprotein (HDL) cholesterol when compared with placebo (111555).
• Pancreatic cancer. It is unclear if oral vitamin B12 is beneficial for reducing the risk of pancreatic cancer. Details: Most population research has found that increased intake of vitamin B12, as a supplement or in the diet, is not associated with a reduced risk of pancreatic cancer (9327,104927). However, a small, retrospective population study in which smoking and non-smoking adults recalled past eating habits found that increased dietary intake of vitamin B12 is associated with a 33% reduction in pancreatic cancer risk (97976). These conflicting findings may be related to study methodology, as well as the age, gender, or smoking status of the included patients.
• Periodontitis. Although there is interest in using oral vitamin B12 for periodontitis, there is insufficient reliable information about the clinical effects of vitamin B12 for this condition.
• Peripheral neuropathy. Oral vitamin B12 has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research shows that taking a specific product containing vitamin B12 3 mcg, folic acid 400 mcg, and uridine monophosphate 50 mg (Keltican) daily for 60 days reduces pain by 44% and decreases analgesic use by over 75% when compared to baseline in patients with peripheral neuropathy, including those with lumbar/lumbosacral radiculopathy, sciatic pain, and cervical radiculopathy (90384). The validity of this finding is limited by the lack of a control group. Furthermore, it is unclear if the benefits are due to vitamin B12, other ingredients, or the combination.
• Psoriasis. Topical vitamin B12 has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research shows that a specific cream containing vitamin B12 and avocado oil (Regividerm, Regeneratio Pharma AG) reduces symptoms of psoriasis as effectively as calcipotriol ointment (Psorcutan) after 12 weeks of therapy. The vitamin B12 combination cream also causes less irritation than calcipotriol (14909). It is unclear if the benefits are due to vitamin B12, other ingredients, or the combination.
• Respiratory tract infections. A small study suggests that oral vitamin B12 does not reduce the rate of respiratory tract infections in children. Details: Preliminary clinical research in children aged 6-30 months from low-and middle-income countries suggests that taking vitamin B12 at twice the recommended dietary allowance with or without folic acid does not reduce the risk for lower respiratory tract infections when compared with placebo (90391).
• Schizophrenia. Oral vitamin B12 has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Clinical research shows that taking a combination of vitamin B12 400 mcg and folic acid 2 mg daily for 16 weeks improves negative symptoms when compared with placebo in patients with schizophrenia who have persistent symptoms and a specific genetic variant of the folate transporter gene FOLHI. This variant normally results in reduced folate absorption. However, in patients without this genetic variant, folate is not beneficial with respect to negative symptom improvement (90387).
• Sickle cell disease. Oral vitamin B12 has only been evaluated in combination with other B vitamins; its effect when used alone is unclear. Details: Preliminary clinical research in adults with sickle cell disease shows that taking vitamin B12 4.2-6 mcg, folic acid 700 mcg, and vitamin B6 4.2-6 mg daily might lower homocysteine levels. However, it is unknown if this will reduce the risk of endothelial damage in these patients (9324).
• Stroke. It is unclear if oral vitamin B12, either alone or with other B vitamins, is beneficial for stroke prevention. Details: Epidemiological research has found that people with a higher intake of vitamin B12 from dietary sources do not have a reduced risk of ischemic or hemorrhagic stroke (14316). A number of clinical studies and meta-analyses show that supplementation with folic acid, vitamin B6, and vitamin B12, alone or in combination, does not reduce the risk of stroke in patients with cardiovascular disease (CVD) or impaired kidney function (11387,13482,50420,50423,83050,90379,90380,96150). However, a more recent meta-analysis of 10 clinical trials including over 44,000 patients shows that B vitamin supplementation modestly reduces the relative risk of stroke by 10% when compared with placebo in patients at risk or with a history of CVD (97619). This meta-analysis differed from some of the earlier analyses due to the inclusion of several additional clinical trials. Also, a meta-analysis in adults with a history of stroke shows that B vitamin supplementation modestly reduces the relative risk of stroke recurrence by 13% and vascular death by 11% when compared with placebo (107136). In 2001, prior to the publication of the highest quality research on this topic, the US Food and Drug Administration (FDA) allowed a qualified health claim stating that, as part of a well-balanced diet that is low in saturated fat and cholesterol, folic acid, vitamin B6, and vitamin B12 may reduce the risk of vascular disease (102368). Unfortunately, even after the publication of higher quality research, it is still unclear which specific combination of B vitamins is optimal and which patients are most likely to benefit. One network meta-analysis suggests that a combination of folic acid and vitamin B6 lowers the risk of stroke more effectively than B vitamin mixtures that include vitamin B12 (96165). However, this analysis is limited because it didn't account for dosing. Another meta-analysis suggests that exposure to low, but not high, amounts of vitamin B12 (cyanocobalamin) seems to reduce stroke risk (96150).
• Tinnitus. It is unclear if intramuscular vitamin B12 is beneficial in patients with tinnitus. Details: A small clinical study shows that intramuscular vitamin B12 2500 mcg weekly for 6 weeks reduces tinnitus severity by 22% when compared to baseline in patients with chronic tinnitus and vitamin B12 deficiency, but not in patients with normal levels of vitamin B12. Vitamin B12 does not improve pitch or volume in either group of patients (96170). The validity of this finding is limited by the lack of a control group.
• Venous thromboembolism (VTE). It is unclear if oral vitamin B12 is beneficial for preventing VTE. Details: Epidemiological research has found that low levels of vitamin B12 are associated with an increased risk for VTE. However, clinical trials evaluating the use of B vitamins for prevention of VTE have shown conflicting results (90398). More evidence is needed to rate vitamin B12 for these uses.

(Read more about VITAMIN B12)

POSSIBLY SAFE ...when used orally and appropriately, short-term. Bacopa has been used safely in clinical trials at a dose of up to 600 mg daily for up to 12 weeks (10058,10059,17946,97605).

CHILDREN: POSSIBLY SAFE
when used orally and appropriately, short-term. Clinical research suggests bacopa extract might be safe to use at a dose of 225 mg daily for up to 6 months or 320 mg daily for up to 14 weeks in children aged 6-14 years (33304,97603,109625).

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

(Read more about BACOPA)

POSSIBLY SAFE ...when used orally and appropriately. Deanol has been safely used at doses up to 2 grams daily for up to 4 weeks and doses up to 500 mg daily for up to 3 months (1668,1671,1672,1673,1674,1675,1676,1679,1680,1681). There is insufficient reliable information available about the safety of deanol when used topically.

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

(Read more about DEANOL)

LIKELY SAFE ...when used orally and appropriately. Standardized ginkgo leaf extracts have been used safely in trials lasting for several weeks up to 6 years (1514,1515,3461,5717,5718,6211,6212,6213,6214,6215)(6216,6222,6223,6224,6225,6490,14383,14499,16634,16635)(16636,16637,17402,17716,17718,87794,87819,87826,87848,87864)(87888,87897,87901,87904,89701,89707,107359,107360). There have been some reports of arrhythmias associated with ginkgo leaf extract. However, it is not yet clear if ginkgo might cause arrhythmia (105253,105254). There is some concern about toxic and carcinogenic effects seen in animals exposed to a ginkgo leaf extract containing 31.2% flavonoids, 15.4% terpenoids, and 10.45 ppm ginkgolic acid, in doses of 100 to 2000 mg/kg five times per week for 2 years (18272). However, the clinical relevance of this data for humans, using typical doses, is unclear. The content of the extract used is not identical to that commonly used in supplement products, and the doses studied are much higher than those typically used by humans. A single dose of 50 mg/kg in rats is estimated to be equivalent to a single dose of about 240 mg in humans (18272).

POSSIBLY SAFE ...when used intravenously, short-term. A standardized ginkgo leaf extract called EGb 761 ONC has been safely administered intravenously for up to 14 days (9871,9872,107360,107452). A Chinese preparation containing ginkgo leaf extract and dipyridamole has been safely administered intravenously for up to 30 days (102881,102882). ...when applied topically, short-term. There was no dermal irritation during a 24-hour patch test using the leaf extract, and no sensitization with repeat applications (112946). When used topically in cosmetics, extracts of ginkgo leaves are reported to be safe, but there is insufficient data to determine the safety of nut and root extracts, and isolated biflavones and terpenoids (112946).

POSSIBLY UNSAFE ...when the roasted seed or crude ginkgo plant is used orally. Consuming more than 10 roasted seeds per day can cause difficulty breathing, weak pulse, seizures, loss of consciousness, and shock (8231,8232). Crude ginkgo plant parts can exceed concentrations of 5 ppm of the toxic ginkgolic acid constituents and can cause severe allergic reactions (5714).

LIKELY UNSAFE ...when the fresh ginkgo seed is used orally. Fresh seeds are toxic and potentially deadly (11296).

PREGNANCY: POSSIBLY UNSAFE
when used orally. There is concern that ginkgo might have labor-inducing and hormonal effects. There is also concern that the antiplatelet effects of ginkgo could prolong bleeding time if taken around the time of labor and delivery (15052). Theoretically, ginkgo might adversely affect pregnancy outcome; avoid using during pregnancy.

LACTATION:
Insufficient reliable information available; avoid using.

CHILDREN: POSSIBLY SAFE
when used orally and appropriately, short-term (87790,89708). A specific ginkgo dried extract (Ginko T.D., Tolidaru Pharmaceuticals), has been safely used in doses of 80-120 mg daily for 6 weeks in children aged 6-14 years (17112,95669). Another specific combination product containing ginkgo leaf extract and American ginseng extract (AD-FX, CV Technologies, Canada) has also been safely used in children aged 3-17 years for up to 4 weeks (8235).

CHILDREN: LIKELY UNSAFE
when ginkgo seed is used orally. The fresh seeds have caused seizures and death in children (8231,11296).

(Read more about GINKGO)

POSSIBLY SAFE ...when used orally and appropriately. Phosphatidylserine has been used with apparent safety at dose of up to 300 mg daily for up to 6 months (2255,2437,2438,2439,2440,2441,7118,15539,68855).

CHILDREN: POSSIBLY SAFE
when used orally and appropriately, short-term (7117). Phosphatidylserine has been used with apparent safety in clinical research in doses of 200-300 mg daily for up to 4 months in children aged 4-18 years (7117,89498).

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

(Read more about PHOSPHATIDYLSERINE)

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.

(Read more about RHODIOLA)

LIKELY SAFE ...when used orally, topically, intravenously, intramuscularly, or intranasally and appropriately. Vitamin B12 is generally considered safe, even in large doses (15,1344,1345,1346,1347,1348,2909,6243,7289,7881)(9414,9416,10126,14392,15765,82832,82949,82860,82864,90386)(111334,111551).

PREGNANCY: LIKELY SAFE
when used orally in amounts that do not exceed the recommended dietary allowance (RDA). The RDA for vitamin B12 during pregnancy is 2.6 mcg daily (6243). There is insufficient reliable information available about the safety of larger amounts of vitamin B12 during pregnancy.

LACTATION: LIKELY SAFE
when used orally in amounts that do not exceed the recommended dietary allowance (RDA). The RDA of vitamin B12 during lactation is 2.8 mcg daily (6243). There is insufficient reliable information available about the safety of larger amounts of vitamin B12 while breastfeeding.

(Read more about VITAMIN B12)

ANTICHOLINERGIC DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, concurrent use might decrease the effectiveness of both agents.  Details Bacopa seems to inhibit acetylcholinesterase and might increase acetylcholine levels, which could counteract the effects of anticholinergic drugs (17946). Similarly, anticholinergic drugs might counteract the cholinergic effects of bacopa.

CEVIMELINE (Evoxac) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, bacopa might increase the effects and adverse effects of cevimeline.  Details In one case, a 58-year-old female taking cevimeline long-term for Sjogren syndrome experienced hyperhidrosis, malaise, nausea, and tachycardia shortly after taking a single dose of bacopa. Symptoms resolved after two days. Cevimeline is metabolized by cytochrome P450 (CYP) 2D6 and CYP3A4, and researchers theorize that bacopa may have inhibited these isoenzymes (109627). However, it is unclear if bacopa causes clinically significant inhibition of either CYP2D6 or CYP3A4.

CHOLINERGIC DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, concurrent use of bacopa with other cholinergic drugs might have additive effects.  Details Bacopa seems to inhibit acetylcholinesterase and might increase acetylcholine levels (17946). Theoretically, this could result in additive cholinergic effects when used with cholinergic drugs.

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, bacopa might increase the levels and adverse effects of CYP1A2 substrates.  Details Research on the effects of bacopa extracts on CYP1A2 enzymes is conflicting. Some in vitro evidence shows that bacopa extract can moderately and non-competitively inhibit CYP1A2, while other in vitro evidence suggests that any effect is unlikely to be clinically significant (97269,97606).

CYTOCHROME P450 2C19 (CYP2C19) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, bacopa might increase the levels and adverse effects of CYP2C19 substrates.  Details In vitro evidence suggests that bacopa extract can moderately and non-competitively inhibit CYP2C19 enzymes (97606). It is not known whether this is clinically significant.

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, bacopa might increase the levels and adverse effects of CYP2C9 substrates.  Details Research on the effect of bacopa extracts on CYP2C9 enzymes is conflicting. Some in vitro evidence suggests that bacopa extract can moderately and non-competitively inhibit CYP2C9, while other in vitro evidence suggests that any effect is unlikely to be clinically significant (97269,97606).

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, bacopa might increase the levels and adverse effects of CYP3A4 substrates.  Details Research on the effects of bacopa extracts on CYP3A4 enzymes is conflicting. Some in vitro evidence suggests that bacopa extract can moderately and competitively inhibit CYP3A4, while other in vitro evidence suggests that any effect is unlikely to be clinically significant (97269,97606).

THYROID HORMONE Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, bacopa might have additive effects when used with thyroid hormone.  Details Animal research suggests that bacopa increases thyroxine (T4) levels in mice by about 40% (33286).

(Read more about BACOPA)

ANTICHOLINERGIC DRUGS Interaction Rating = Minor Be watchful with this combination. Severity = Moderate •  Occurrence = Unlikely •  Level of Evidence = D Theoretically, deanol might decrease the effectiveness of anticholinergic drugs.  Details Deanol is thought to increase acetylcholine levels (1669).

CHOLINERGIC DRUGS Interaction Rating = Minor Be watchful with this combination. Severity = Moderate •  Occurrence = Unlikely •  Level of Evidence = D Theoretically, deanol might increase the effects and adverse effects of cholinergic drugs.  Details Deanol is thought to increase acetylcholine levels (1669).

(Read more about DEANOL)

ALPRAZOLAM (Xanax) Interaction Rating = Moderate Be cautious with this combination. Severity = Mild •  Occurrence = Probable •  Level of Evidence = B Theoretically, ginkgo might decrease the levels and clinical effects of alprazolam.  Details In clinical research, ginkgo extract (Ginkgold) 120 mg twice daily seems to decrease alprazolam levels by about 17%. However, ginkgo does not appear to decrease the elimination half-life of alprazolam. This suggests that ginkgo is more likely to decrease absorption of alprazolam rather than induce hepatic metabolism of alprazolam (11029).

ANTICOAGULANT/ANTIPLATELET DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = A Ginkgo has been shown to increase the risk of bleeding in some people when taken with warfarin. Theoretically, ginkgo might increase the risk of bleeding if used with other anticoagulant or antiplatelet drugs.  Details Several pharmacodynamic studies suggest that ginkgo inhibits platelet aggregation. It is thought that the ginkgo constituent, ginkgolide B, displaces platelet-activating factor (PAF) from its binding sites, decreasing blood coagulation (6048,9760). Several case reports have documented serious bleeding events in patients taking ginkgo (244,578,579,8581,13002,13135,13179,13194,14456,87868). However, population and clinical studies have produced mixed results. Some evidence shows that short-term use of ginkgo leaf does not significantly reduce platelet aggregation and blood clotting (87732). A study in healthy males who took a specific ginkgo leaf extract (EGb 761) 160 mg twice daily for 7 days found no change in prothrombin time (12114). An analysis of a large medical record database suggests that ginkgo increases the risk of a bleeding adverse event by 38% when taken concurrently with warfarin (91326). It has been suggested that ginkgo has to be taken for at least 2-3 weeks to have a significant effect on platelet aggregation (14811). However, a meta-analysis of 18 studies using standardized ginkgo extracts, 80-480 mg daily for up to 32 weeks, did not find a significant effect on platelet aggregation, fibrinogen concentration, or PT/aPTT (17179). In addition, a single dose of ginkgo plus clopidogrel (14811) or ticlopidine does not seem to significantly increase bleeding time or platelet aggregation (17111,87846). Also, taking ginkgo leaf extract daily for 8 days in conjunction with rivaroxaban does not affect anti-factor Xa activity; however, this study did not evaluate bleeding time (109526).

ANTICONVULSANTS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, ginkgo might reduce the effectiveness of anticonvulsants.  Details Ginkgo seeds contain ginkgotoxin. Large amounts of ginkgotoxin can cause neurotoxicity and seizure. Ginkgotoxin is present in much larger amounts in ginkgo seeds than leaves (8232). Ginkgo leaf extract contains trace amounts of ginkgotoxin. The amount of ginkgotoxin in ginkgo leaf and leaf extract seems unlikely to cause toxicity (11296). However, there are anecdotal reports of seizure occurring after use of ginkgo leaf both in patients without a history of seizure disorder and in those with previously well-controlled epilepsy (7030,7090).

ANTIDIABETES DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Theoretically, taking ginkgo with antidiabetes drugs might alter the response to antidiabetes drugs.  Details Ginkgo leaf extract seems to alter insulin secretion and metabolism, and might affect blood glucose levels in people with type 2 diabetes (5719,14448,103574). The effect of ginkgo seems to differ depending on the insulin and treatment status of the patient. In diet-controlled diabetes patients with hyperinsulinemia, taking ginkgo does not seem to significantly affect insulin or blood glucose levels. In patients with hyperinsulinemia who are treated with oral hypoglycemic agents, taking ginkgo seems to decrease insulin levels and increase blood glucose following an oral glucose tolerance test. Researchers speculate that this could be due to ginkgo-enhanced hepatic metabolism of insulin. In patients with pancreatic exhaustion, taking ginkgo seems to stimulate pancreatic beta-cells, resulting in increased insulin and C-peptide levels, but with no significant change in blood glucose levels in response to an oral glucose tolerance test (14448).

ATORVASTATIN (Lipitor) Interaction Rating = Moderate Be cautious with this combination. Severity = Mild •  Occurrence = Probable •  Level of Evidence = B Theoretically, ginkgo might decrease the levels and clinical effects of atorvastatin.  Details In humans, intake of ginkgo extract appears to increase atorvastatin clearance, reducing the area under the curve of atorvastatin by 10% to 14% and the maximum concentration by 29%. However, this interaction does not appear to affect cholesterol synthesis and absorption (89706). Further, a model in rats with hyperlipidemia suggests that administering ginkgo extract does not impact blood levels of atorvastatin and leads to lower total cholesterol, low-density lipoprotein cholesterol, and triglycerides when compared with rats given atorvastatin alone (111331).

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Theoretically, ginkgo might increase levels of drugs metabolized by CYP1A2.  Details Laboratory research suggests that ginkgo leaf extract can mildly inhibit CYP1A2 enzymes (1303,6423,6450). However, clinical research suggests ginkgo might not affect CYP1A2 (10847). Until more is known, use ginkgo cautiously in patients taking drugs metabolized by these enzymes.

CYTOCHROME P450 2C19 (CYP2C19) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Theoretically, ginkgo might decrease levels of drugs metabolized by CYP2C19.  Details Some clinical research shows that a specific ginkgo leaf extract (Remembrance, Herbs Product LTD) 140 mg twice daily can induce CYP2C19 enzymes and potentially decrease levels of drugs metabolized by these enzymes (13108). However, other clinical research shows that taking ginkgo 120 mg twice daily for 12 days has no effect on levels of drugs metabolized by CYP2C19 (87824).

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, ginkgo might increase levels of drugs metabolized by CYP2C9.  Details In vitro, a specific standardized extract of ginkgo leaf (EGb 761) inhibits CYP2C9 activity (11026,12061,14337). The terpenoid (ginkgolides) and flavonoid (quercetin, kaempferol, etc.) constituents seem to be responsible for this effect. Most ginkgo extracts contain some amount of these constituents. Therefore, other ginkgo leaf extracts might also inhibit the CYP2C9 enzyme. However, clinical research suggests that ginkgo might not have a significant effect on CYP2C9 in humans. Ginkgo does not seem to significantly affect the pharmacokinetics of CYP2C9 substrates diclofenac or tolbutamide.

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Theoretically, ginkgo might decrease levels of drugs metabolized by CYP3A4.  Details There is conflicting evidence about whether ginkgo induces or inhibits CYP3A4 (1303,6423,6450,11026,87800,87805,111330). Ginkgo does not appear to affect hepatic CYP3A4 (11029). However, it is not known if ginkgo affects intestinal CYP3A4. Preliminary clinical research suggests that taking ginkgo does not significantly affect levels of donepezil, lopinavir, or ritonavir, which are all CYP3A4 substrates (11027,87800,93578). Other clinical research also suggests ginkgo does not significantly affect CYP3A4 activity (10847). However, there are two case reports of decreased efavirenz concentrations and increased viral load in patients taking ginkgo. It is suspected that terpenoids from the ginkgo extract reduced drug levels by inducing cytochrome P450 3A4 (CYP3A4) (16821,25464).

EFAVIRENZ (Sustiva) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, ginkgo might decrease the levels and clinical effects of efavirenz.  Details There are two case reports of decreased efavirenz concentrations and increased viral load in patients taking ginkgo. In one case, an HIV-positive male experienced over a 50% decrease in efavirenz levels over the course of 14 months while taking ginkgo extract. HIV-1 RNA copies also increased substantially, from less than 50 to more than 1500. It is suspected that terpenoids from the ginkgo extract reduced drug levels by inducing cytochrome P450 3A4 (CYP3A4) (16821). In another case report, a patient stable on antiviral therapy including efavirenz for 10 years, had an increase in viral load from <50 copies/mL to 1350 copies/mL after 2 months of taking a combination of supplements including ginkgo. After stopping ginkgo, the viral load was again controlled with the same antiviral therapy regimen (25464).

IBUPROFEN (Advil, others) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, ginkgo might increase the risk of bleeding when used with ibuprofen.  Details Ginkgo might have antiplatelet effects and has been associated with several case reports of spontaneous bleeding. In one case, a 71-year-old male had taken a specific ginkgo extract (Gingium, Biocur) 40 mg twice daily for 2.5 years. About 4 weeks after starting ibuprofen 600 mg daily he experienced a fatal intracerebral hemorrhage (13179). However, the antiplatelet effects of ginkgo have been questioned. A meta-analysis and other studies have not found a significant antiplatelet effect with standardized ginkgo extracts, 80 mg to 480 mg taken daily for up to 32 weeks (17179).

NIFEDIPINE (Procardia) Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = B Theoretically, taking ginkgo with oral, but not intravenous, nifedipine might increase levels and adverse effects of nifedipine.  Details Animal research and some clinical evidence suggests that taking ginkgo leaf extract orally in combination with oral nifedipine might increase nifedipine levels and cause increased side effects, such as headaches, dizziness, and hot flushes (87764,87765). However, taking ginkgo orally does not seem to affect the pharmacokinetics of intravenous nifedipine (87765).

OMEPRAZOLE (Prilosec) Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = B Theoretically, taking ginkgo with omeprazole might decrease the levels and clinical effects of omeprazole.  Details Clinical research shows that a specific ginkgo leaf extract (Remembrance, Herbs Product LTD) 140 mg twice daily can induce cytochrome P450 (CYP) 2C19 enzymes and decrease levels of omeprazole by about 27% to 42% (13108).

P-GLYCOPROTEIN SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = B Theoretically, taking ginkgo with P-glycoprotein substrates might increase the levels and adverse effects of these substrates.  Details A small clinical study in healthy volunteers shows that using ginkgo leaf extract 120 mg orally three times daily for 14 days can increase levels of the P-glycoprotein substrate, talinolol, by 36% in healthy male individuals. However, single doses of ginkgo do not have the same effect (87830).

RISPERIDONE (Risperdal) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, taking ginkgo with risperidone might increase the levels and adverse effects of risperidone.  Details A single case of priapism has been reported for a 26-year-old male with schizophrenia who used risperidone 3 mg daily along with ginkgo extract 160 mg daily (87796). Risperidone is metabolized by cytochrome P450 (CYP) 2D6 and CYP3A4. CYP3A4 activity might be affected by ginkgo. Theoretically, ginkgo may inhibit the metabolism of risperidone and increase the risk of adverse effects.

ROSIGLITAZONE (Avandia) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, ginkgo might decrease the levels and clinical effects of rosiglitazone.  Details Animal research shows that ginkgo leaf extract orally 100 or 200 mg/kg daily for 10 days alters the pharmacodynamics of rosiglitazone in a dose-dependent manner. The 100 mg/kg and 200 mg/kg doses reduce the area under the concentration time curve (AUC) of rosiglitazone by 39% and 52%, respectively, and the half-life by 28% and 39%, respectively. It is hypothesized that these changes may be due to induction of cytochrome P450 2C8 by ginkgo (109525).

SEIZURE THRESHOLD LOWERING DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, taking ginkgo with drugs that lower the seizure threshold might increase the risk for convulsions.  Details Ginkgo seeds contain ginkgotoxin. Large amounts of ginkgotoxin can cause neurotoxicity and seizure. Ginkgotoxin is present in much larger amounts in ginkgo seeds than leaves (8232). Ginkgo leaf extract contains trace amounts of ginkgotoxin. The amount of ginkgotoxin in ginkgo leaf and leaf extract seems unlikely to cause toxicity (11296). However, there are anecdotal reports of seizure occurring after use of ginkgo leaf both in patients without a history of seizure disorder and in those with previously well-controlled epilepsy (7030,7090,14281).

SIMVASTATIN (Zocor) Interaction Rating = Moderate Be cautious with this combination. Severity = Mild •  Occurrence = Probable •  Level of Evidence = B Theoretically, ginkgo might decrease the levels and clinical effects of simvastatin.  Details Clinical research shows that taking ginkgo extract can reduce the area under the curve and maximum concentration of simvastatin by 32% to 39%. However, ginkgo extract does not seem to affect the cholesterol-lowering ability of simvastatin (89704).

SOFOSBUVIR (Sovaldi) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, ginkgo might increase the levels and clinical effects of sofosbuvir.  Details Animal research in rats shows that giving a ginkgo extract 25 mg/kg orally daily for 14 days increases the area under the concentration time curve (AUC) after a single sofosbuvir dose of 40 mg/kg by 11%, increases the half-life by 60%, and increases the plasma concentration at 4 hours by 38%. This interaction appears to be related to the inhibition of intestinal P-glycoprotein by ginkgo (109524).

TACROLIMUS (Prograf) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, ginkgo might increase the blood levels of tacrolimus.  Details In vitro evidence suggests that certain biflavonoids in ginkgo leaves (i.e. amentoflavone, ginkgetin, bilobetin) may inhibit the metabolism of tacrolimus by up to 50%. This interaction appears to be time-dependent and due to inhibition of cytochrome P450 (CYP) 3A4 by these bioflavonoids. In rats given tacrolimus 1 mg/kg orally, amentoflavone was shown to increase the area under the concentration time curve (AUC) of tacrolimus by 3.8-fold (111330).

TALINOLOL Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Taking ginkgo with talinolol seems to increase blood levels of talinolol.  Details There is some evidence that using ginkgo leaf extract 120 mg orally three times daily for 14 days can increase levels of talinolol by 36% in healthy male individuals. However, single doses of ginkgo do not seem to affect talinolol pharmacokinetics (87830).

TRAZODONE (Desyrel) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, ginkgo might increase the levels and clinical effects of trazodone.  Details In a case report, an Alzheimer patient taking trazodone 20 mg twice daily and ginkgo leaf extract 80 mg twice daily for four doses became comatose. The coma was reversed by administration of flumazenil (Romazicon). Coma might have been induced by excessive GABA-ergic activity. Ginkgo flavonoids are thought to have GABA-ergic activity and act directly on benzodiazepine receptors. Ginkgo might also increase metabolism of trazodone to active GABA-ergic metabolites, possibly by inducing cytochrome P450 3A4 (CYP3A4) metabolism (6423).

WARFARIN (Coumadin) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = B Ginkgo has been shown to increase the risk of bleeding in some people when taken with warfarin.  Details Several pharmacodynamic studies suggest that ginkgo inhibits platelet aggregation. It is thought that the ginkgo constituent, ginkgolide B, displaces platelet-activating factor (PAF) from its binding sites, decreasing blood coagulation (6048,9760). Several case reports have documented serious bleeding events in patients taking ginkgo (244,576,578,579,8581,13002,13135,13179,13194,14456,87868). Information from a medical database suggests that when taken concurrently with warfarin, ginkgo increases the risk of a bleeding adverse event by 38% (91326). There is also some evidence that ginkgo leaf extract can inhibit cytochrome P450 2C9, an enzyme that metabolizes warfarin. This could result in increased warfarin levels (12061). However, population and clinical research has produced mixed results. Clinical research in healthy people suggests that ginkgo has no effect on INR, or the pharmacokinetics or pharmacodynamics of warfarin (12881,15176,87727,87889). A meta-analysis of 18 studies using standardized ginkgo extracts, 80 mg to 480 mg daily for up to 32 weeks, did not find a significant effect on platelet aggregation, fibrinogen concentration, or PT/aPTT (17179). There is also some preliminary clinical research that suggests ginkgo might not significantly increase the effects of warfarin in patients that have a stable INR (11905).

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ANTICHOLINERGIC DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Theoretically, phosphatidylserine might decrease the effectiveness anticholinergic drugs.  Details Phosphatidylserine is thought to increase acetylcholine levels (2437,8857,8858), which could theoretically interfere with the activity of anticholinergic agents.

CHOLINERGIC DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Theoretically, phosphatidylserine might have additive effects with cholinergic drugs.  Details Phosphatidylserine is thought to increase acetylcholine levels (2437,8857,8858), which could theoretically lead to additive cholinergic effects when used with cholinergic drugs.

(Read more about PHOSPHATIDYLSERINE)

ANTIDIABETES DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, taking rhodiola with antidiabetes drugs might increase the risk of hypoglycemia.  Details In vitro and animal research shows that rhodiola extract can decrease blood glucose due to alpha-glucosidase activity (15717,15719).

ANTIHYPERTENSIVE DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, taking rhodiola with antihypertensive drugs might increase the risk of hypotension.  Details In vitro and animal research shows that rhodiola extract inhibits angiotensin-converting enzyme (ACE) and might lower blood pressure (15719,19495).

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = B Theoretically, rhodiola might increase levels of drugs metabolized by CYP1A2.  Details In vitro research shows that rhodiola inhibits CYP1A2. This effect is highly variable and appears to be dependent on the rhodiola product studied (96461). However, a clinical study in healthy young males found that taking rhodiola extract 290 mg daily for 14 days does not inhibit the metabolism of caffeine, a CYP1A2 substrate (96463).

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Theoretically, rhodiola might increase levels of drugs metabolized by CYP2C9.  Details In vitro research shows that rhodiola inhibits CYP2C9. This effect is highly variable and appears to be dependent on the rhodiola product studied (96461). Also, a clinical study in healthy young males found that taking rhodiola extract 290 mg daily for 14 days reduces the metabolism of losartan, a CYP2C9 substrate, by 21% after 4 hours (96463).

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = B Theoretically, rhodiola might increase levels of drugs metabolized by CYP3A4.  Details In vitro research shows that rhodiola inhibits CYP3A4 (19497,96461). This effect is highly variable and appears to be dependent on the rhodiola product studied (96461). However, a clinical study in healthy young males found that taking rhodiola extract 290 mg daily for 14 days does not inhibit the metabolism of midazolam, a CYP3A4 substrate (96463).

IMMUNOSUPPRESSANTS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, rhodiola use might interfere with immunosuppressive therapy.  Details In vitro and animal research show that rhodiola has immunostimulatory effects (19498,19499,19500,19501).

LOSARTAN (Cozaar) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Rhodiola might increase the levels and adverse effects of losartan.  Details A clinical study in healthy young males found that taking rhodiola extract 290 mg daily for 14 days reduces the metabolism of losartan, a CYP2C9 substrate, by 21% after 4 hours (96463).

P-GLYCOPROTEIN SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, rhodiola might increase levels of P-glycoprotein substrates.  Details In vitro research shows that rhodiola inhibits P-glycoprotein (19497). Theoretically, using rhodiola with P-glycoprotein substrates might increase drug levels and potentially increase the risk of adverse effects.

(Read more about RHODIOLA)

(Read more about VITAMIN B12)

General ...Orally, bacopa is generally well tolerated.
Most Common Adverse Effects:
Orally: Abdominal cramps, diarrhea, dry mouth, headache, nausea.

Cardiovascular ...Orally, bacopa has been reported to cause palpitations (10058).

Gastrointestinal ...Orally, bacopa has been reported to cause abdominal cramps, abdominal pain, bloating, decreased appetite, diarrhea, dry mouth, excessive thirst, flatulence, indigestion, nausea, and increased stool frequency. Rates of adverse gastrointestinal events have ranged from 12% to 30% (10058,17946,33295,97605,109623,111520).

Musculoskeletal ...Orally, bacopa has been reported to cause arthralgia, muscle fatigue, and myopathy (10058,109623,111522). In one case, a 21-year-old male experienced progressive proximal weakness, muscle atrophy, weight loss, dark urine, and elevated serum markers of myopathy, with muscle biopsy showing immune-mediated necrotizing myopathy, after taking a supplement containing bacopa for 5 years (111522).

Neurologic/CNS ...Orally, bacopa has been reported to cause drowsiness, headache, insomnia, and vivid dreams (10058,10059,17946,109623).

Other ...Orally, bacopa has been reported to cause flu like symptoms and fatigue (10058,97605,111520).

(Read more about BACOPA)

General ...Orally, deanol seems to be well tolerated (1668,1671,1672,1673,1674,1675,1676,1679,1680,1681). However, deanol has been reported to cause constipation, diarrhea, urticaria, headache, drowsiness, insomnia, overstimulation, lucid dreams, confusion, motor retardation, depression, hypomania, and an increase in schizophrenia symptoms (1674,1680,1684,1685,1686,2706).
Most Common Adverse Effects:
Orally: Abdominal cramps, abdominal pain, diarrhea, drowsiness, nausea, vomiting.

Cardiovascular ...Orally, small elevations in blood pressure have been reported in some patients taking deanol up to 1800 mg daily. These effects improved after deanol discontinuation (1680).

Gastrointestinal ...Orally, deanol has been reported to cause diarrhea, abdominal cramps, abdominal pain, nausea, and vomiting (1674,1680).

Musculoskeletal ...Orally, deanol up to 1800 mg daily has been reported to cause motor retardation in a small number of patients. This effect improved after deanol discontinuation (1680).

Neurologic/CNS ...Orally, deanol has been reported to cause drowsiness, apathy, and confusion (1674,1680). In one case report, a physician promoted the use of deanol to induce lucid dreams, which may be considered an undesirable outcome for some patients (1686).

Psychiatric ...Orally, taking deanol at doses greater than 1000 mg daily has been reported to cause mood changes, including depression and hypomania, in patients with psychiatric conditions (1685). Deanol 1500 mg daily has been reported to increase schizophrenic symptoms in patients with chronic schizophrenia (1674).

(Read more about DEANOL)

General ...Orally, ginkgo leaf extract is generally well tolerated when used for up to 6 years. However, the seed and crude plant contain toxic constituents and should be avoided.
Intravenously, ginkgo leaf extract seems to be well tolerated when used for up to 30 days.
Topically, no adverse effects have been reported with ginkgo as a single ingredient. However, a thorough evaluation of safety outcomes has not been conducted.
Most Common Adverse Effects:
Orally: Dizziness, gastrointestinal symptoms, headache.
Serious Adverse Effects (Rare):
Orally: Arrhythmia, bleeding, Stevens-Johnson syndrome.

Cardiovascular ...Cardiac arrhythmias suspected to be related to ginkgo have been reported. Internationally, there are at least 162 reports from 18 countries, with 34% of cases considered serious, involving five deaths and four life-threatening events. Additionally, a report from Canada found that 10 out of 15 cases of arrhythmia were considered serious. Ginkgo was the only suspect ingredient in 57% of all international reports, with symptoms generally presenting within days of initiation. The most common symptoms included palpitations, tachycardia, bradycardia, syncope, and loss of consciousness. Most cases were reported to be related to oral use of ginkgo leaf products; however, some cases were associated with oral use of the seed, and others with intravenous or intramuscular use of the leaf. Documented discontinuation of ginkgo led to recovery in approximately 84% of cases where ginkgo was the sole suspect. Despite these findings, ginkgo cannot be confirmed as the causal agent. It is possible that these reports are confounded by underlying co-morbidities. Of the reported cases, the main reason for ginkgo use was tinnitus, a symptom commonly associated with pre-existing arrhythmias (105253,105254). Despite this large number of reports, only three cases of cardiac arrhythmia have been published in the literature (105253,105254). In one case, frequent nocturnal episodes of paroxysmal atrial fibrillation were reported for a 35-year-old female taking ginkgo extract 240 mg daily orally for 2 months. Arrythmias ceased following discontinuation of ginkgo (87884).
Increases in blood pressure were commonly reported with ginkgo in a safety database analysis; however, information on the magnitude of the increase was limited, and reports included both oral and intravenous administration (115628).
In one clinical trial, the rate of ischemic stroke and transient ischemic attacks was significantly higher in patients taking ginkgo extract orally when compared with placebo (16635). It is unclear if these events were due to ginkgo, other factors, or a combination.

Dermatologic ...Topically, ginkgo fruit pulp can cause contact dermatitis, with intense itching, edema, papules, and pustules which take 7-10 days to resolve after stopping contact (112946).

Gastrointestinal ...Orally, ginkgo extract may cause mild gastrointestinal discomfort or pain (3965,8543,17112,87818,87858), nausea and vomiting (8543,17112,87728,87844,87858), diarrhea (87844), dry mouth (17112), and constipation (5719,87787). However, post-market surveillance suggests that the incidence of these events is relatively low, occurring in less than 2% of patients (88007).
Fresh ginkgo seeds can cause stomach ache, nausea, vomiting, or diarrhea. Ingesting roasted seeds in amounts larger than the normal food amounts of 8-10 seeds per day, or long-term, can also cause these same adverse reactions (8231,8232).

Genitourinary ...Orally, ginkgo extract has been reported to cause blood in the urine (87858,115628).

Hematologic ...Spontaneous bleeding is one of the most concerning potential side effects associated with ginkgo. There are several published case reports linking ginkgo to episodes of minor to severe bleeding; however, not all case reports clearly establish ginkgo as the cause of bleeding. In most cases, other bleeding risk factors were also present including taking other medications or natural medicines, old age, liver cirrhosis, recent surgery, and other conditions. In most cases, bleeding occurred after several weeks or months of taking ginkgo (13135). Large-scale clinical trials and a meta-analysis evaluating standardized ginkgo leaf extracts show that the incidence of bleeding in patients taking ginkgo is not significantly higher than in those taking placebo (16634,16635,17179,17402).
There are several case reports of intracerebral bleeding. Some of these cases resulted in permanent neurological damage and one case resulted in death (244,578,8581,13135,13179,14456,87868,87977).
There are at least 4 cases of ocular bleeding including spontaneous hyphema (bleeding from the iris into the anterior part of the eye) and retrobulbar hemorrhage associated with ginkgo use (579,10450,13135).
There are also cases of surgical and post-surgical complications in patients using ginkgo. Retrobulbar hemorrhage (bleeding behind the eye) during cataract surgery has been associated with ginkgo use (10450). Excessive postoperative bleeding requiring transfusion has also occurred following laparoscopic surgery in a patient who had been taking ginkgo leaf extract (887). There have also been two cases of excessive bleeding during surgery and post-surgical hematoma in patients undergoing rhytidoplasty and blepharoplasty (13002). In another case, an elderly patient taking ginkgo experienced excessive postoperative bleeding following total hip arthroplasty (13194). In another case, use of ginkgo following liver transplantation surgery was associated with subphrenic hematoma requiring evacuation by laparotomy. The patient also subsequently experienced vitreous hemorrhage (14315). In another case, an elderly patient who had taken ginkgo chronically experienced excessive post-operative bleeding following an ambulatory surgical procedure (14453).
In another case, an elderly man experienced nose bleeds and ecchymosis following use of ginkgo. One case of diffuse alveolar hemorrhage in a female taking ginkgo and ginseng for over one year has been reported (95670). These instances of bleeding stopped when ginkgo was discontinued, and recurred when the patient started taking ginkgo again (13135).
Persistent bleeding has also occurred following dental surgery (87862) and laparoscopic cholecystectomy (88000). Nosebleed has also been reported as an adverse effect in a clinical trial (87813).

Immunologic ...Orally, ginkgo leaf extract can cause allergic skin reactions in some patients (14449,15578,112946). In one case, a patient developed acute generalized exanthematous pustulosis 48 hours after taking a single-ingredient ginkgo product. The rash resolved within 10 days after discontinuing ginkgo (14449). In another case, progressive erythema of the face, neck, trunk, and extremities occurred after two 60 mg oral doses of ginkgo extract (112946). There is also a case of Stevens-Johnson syndrome following a second administration of a preparation containing ginkgo leaf extract, choline, vitamin B6, and vitamin B12 (208). In another case, systemic edema and severe arthralgia was reported after contact with a ginkgo tree nut and manifested as multifocal lymphadenopathy associated with an allergic reaction on PET/CT scan imaging (95672).

Musculoskeletal ...Edema has been reported for three patients treated with ginkgo extract 40 mg orally three times daily (87818).

Neurologic/CNS ...Orally, ginkgo extract may cause headache (6220,8543,87818), dizziness (5719,87818), increased desire to sleep (87839,115628), and sedation (10893) in some patients. In addition, although ginkgo leaf and ginkgo leaf extract contain only small amounts of ginkgotoxin, there are anecdotal reports of seizure occurring after use of ginkgo leaf preparations both in patients without a history of seizure disorder and in those with previously well-controlled epilepsy (7030,7090,11296,14281).

Ocular/Otic ...Orally, ginkgo may cause tinnitus is some patients (8543,115628).
Topically, eye drops containing ginkgo extract and hyaluronic acid may cause stinging sensations in some people (87829).

Psychiatric ...Orally, ginkgo has been associated with a single case of mood dysregulation. A 50-year-old female with schizophrenia developed irritability, difficulty controlling anger, and agitation after one week of taking ginkgo 80 mg twice daily. The mood changes resolved within 2-3 days of discontinuation. When ginkgo was re-trialed at a later date, the same symptoms reappeared, and again dissipated after discontinuation of the ginkgo product. The relationship between ginkgo and mood dysregulation was considered to be "probable" based on the Naranjo adverse drug reaction probability scale (96763); however, the exact mechanism by which ginkgo may have affected mood regulation is unknown.

(Read more about GINKGO)

General ...Orally, phosphatidylserine is generally well tolerated.
Most Common Adverse Effects:
Orally: Flatulence, gastrointestinal upset, headache, insomnia, and nausea.

Gastrointestinal ...Orally, phosphatidylserine can cause gastrointestinal upset such as flatulence or nausea. Gastrointestinal upset can occur at doses of 200-300 mg/day (7116,7121,15539,68862,90711).

Neurologic/CNS ...Orally, phosphatidylserine can cause insomnia. Insomnia is more likely to occur with a higher dose of 600 mg (7121,68844). Headache has also been reported (90711).

(Read more about PHOSPHATIDYLSERINE)

General ...Orally, rhodiola seems to be well tolerated.
Most Common Adverse Effects:
Orally: Dizziness, increased or decreased production of saliva.

Gastrointestinal ...Orally, rhodiola extract may cause dry mouth or excessive saliva production (16410,16411).

Neurologic/CNS ...Orally, rhodiola extract can cause dizziness (16410).

(Read more about RHODIOLA)

General ...Orally, intramuscularly, and topically, vitamin B12 is generally well-tolerated.
Most Common Adverse Effects:
Intramuscular: Injection site reactions.
Serious Adverse Effects (Rare):
Intramuscularly: Severe hypokalemia has been rarely linked with correction of megaloblastic anemia with vitamin B12.

Cardiovascular ...In human clinical research, an intravenous loading dose of folic acid, vitamin B6, and vitamin B12, followed by daily oral administration after coronary stenting, increased restenosis rates (12150). Hypertension following intravenous administration of hydroxocobalamin has been reported in human research (82870,82864).

Dermatologic ...Orally or intramuscularly, vitamin B12 can cause allergic reactions such as rash, pruritus, erythema, and urticaria. Theoretically, allergic reactions might be caused by the cobalt within the vitamin B12 molecule (82864,90373,90381,103974). In one case report, oral methylcobalamin resulted in contact dermatitis in a 59-year-old Japanese female with a cobalt allergy (103974). In another case report, a 69-year-old female developed a symmetrical erythematous-squamous rash for 5 years after oral vitamin B12 supplementation for 10 years. A patch test confirmed that the systemic allergic dermatitis was due to vitamin B12 supplementation, which resolved 3 months after discontinuation (114578).
Vitamin B12 (intramuscular or oral) has also been associated with at least 19 cases of acneiform eruptions which resolved upon discontinuation of vitamin B12 (90365,90369,90388). High-dose vitamin B12 (20 mcg daily) and vitamin B6 (80 mg daily) have been associated with cases of rosacea fulminans characterized by intense erythema with nodules, papules, and pustules. Symptoms may last up to four months after the supplement is stopped and can be treated with systemic corticosteroids and topical therapy (10998,82870,82871).

Gastrointestinal ...Intravenously, vitamin B12 (hydroxocobalamin) 2. 5-10 grams can cause nausea and dysphagia (82864).

Genitourinary ...Intravenously, vitamin B12 (hydroxocobalamin) 5-15 grams has been associated with chromaturia in clinical research (82870,82871,112282,112264).

Hematologic ...According to case report data, the correction of megaloblastic anemia with vitamin B12 may result in fatal hypokalemia (82914).

Musculoskeletal ...According to case report data, correction of megaloblastic anemia with vitamin B12 has precipitated gout in susceptible individuals (82879).

Neurologic/CNS ...Treatment with vitamin B12 has been rarely associated with involuntary movements in infants with vitamin B12 deficiency (90370,90385,90397). In some cases these adverse reactions were misdiagnosed as seizures or infantile tremor syndrome (90370,90385). These adverse reactions presented 2-5 days after treatment with vitamin B12 and resolved once vitamin B12 was discontinued (90370,90385,90397).

Oncologic ...Although some epidemiological research disagrees (9454), most research has found that elevated plasma levels of vitamin B12 are associated with an increased risk of various types of cancer, including lung and prostate cancers and solid tumors (50411,102383,107743). One study found, when compared with blood levels of vitamin B12 less than 1000 ng/mL, plasma vitamin B12 levels of at least 1000 ng/mL was strongly associated with the occurrence of solid cancer (107743). It is unclear if increased intake of vitamin B12, either through the diet or supplementation, directly affects the risk of cancer. It is possible that having cancer increases the risk of vitamin B12 elevation. However, one observational study has found that the highest quintile of dietary intake of vitamin B12 is associated with a 75% increased incidence of developing esophageal cancer when compared with the lowest quintile in never drinkers, but not drinkers (107147).

Renal ...There is a case report of oxalate nephropathy in a 54-year-old male which was determined to be related to the use of intravenous hydroxocobalamin as treatment for cyanide poisoning. Intermittent hemodialysis was started 5 days after admission, along with a low-oxalate diet, oral calcium acetate, and pyridoxine 5 mg/kg daily (107148). A review of the use of intravenous hydroxocobalamin for suspected cyanide poisoning in 21 intensive care units in France between 2011 and 2017 resulted in a 60% increased odds of acute kidney injury and a 77% increased odds of severe acute kidney injury in the first week. However, biopsies were not conducted and a direct link with use of hydroxocobalamin could not be made (107139).

Other ...Several studies have found that higher vitamin B12 levels may be associated with increased mortality or decreased survival rates in hospitalized elderly patients (82889,82812,82857,82895). Human research has also found a positive correlation between vitamin B12 status and all-cause mortality in Pima Indians with diabetes (82863).

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