Supreme DHEA for Intimacy [Discontinued] by Swanson Passion

Asthma. Although there has been interest in using oral damiana for asthma, there is insufficient reliable information about the clinical effects of damiana for this purpose.
Cognitive function. Although there has been interest in using oral damiana for cognitive function, there is insufficient reliable information about the clinical effects of damiana for this purpose.
Constipation. Although there has been interest in using oral damiana for constipation, there is insufficient reliable information about the clinical effects of damiana for this purpose.
Depression. Although there has been interest in using oral damiana for depression, there is insufficient reliable information about the clinical effects of damiana for this purpose.
Diabetes. Although there has been interest in using oral damiana for diabetes, there is insufficient reliable information about the clinical effects of damiana for this purpose.
Dyspepsia. Although there has been interest in using oral damiana for dyspepsia, there is insufficient reliable information about the clinical effects of damiana for this purpose.
Erectile dysfunction (ED). Oral damiana has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A moderate-sized, open-label clinical study in adults with mild-to-moderate ED shows that taking a specific combination supplement (Icarifil, Anvest Health S.p.A) containing damiana 100 mg, panax ginseng, L-carnitine, L-citrulline, tribulus, and other ingredients daily for 3 months improves patient-reported erectile function when compared to baseline. Additionally, taking the supplement with tadalafil improves some, but not all, patient-reported assessments of erectile function when compared with taking tadalafil alone (114989). It is unclear if this effect is due to damiana, other ingredients, or the combination. Additionally, the interpretation of these results is limited by poor methodology, including the use of per-protocol analysis and lack of a placebo group.
Headache. Although there has been interest in using oral damiana for headache, there is insufficient reliable information about the clinical effects of damiana for this purpose.
Menopausal symptoms. Although there has been interest in using oral damiana for menopausal symptoms, there is insufficient reliable information about the clinical effects of damiana for this purpose.
Obesity. Oral damiana has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in overweight adults shows that taking a combination product containing damiana 36 mg, guarana 95 mg, and yerba mate 112 mg, orally three times daily for 45 days increases weight loss when compared with placebo (11866). It is unclear if this effect is due to damiana, other ingredients, or the combination.
Nocturnal enuresis. Although there has been interest in using oral damiana for nocturnal enuresis, there is insufficient reliable information about the clinical effects of damiana for this purpose.
Sexual dysfunction. Oral damiana 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 combination product containing damiana, L-arginine, Panax ginseng, ginkgo, vitamins, and minerals (ArginMax for Women, Daily Wellness Co.) improves sexual satisfaction and desire, increases orgasm frequency, and reduces vaginal dryness when compared with placebo in females interested in improving their sexual function (46933). It is unclear if this effect is due to damiana, other ingredients, or the combination. More evidence is needed to rate damiana for these uses.

LIKELY EFFECTIVE

Vaginal atrophy. Intravaginal DHEA can reduce pain during intercourse and improve vaginal health in patients with this condition. Details: Clinical research shows that ovules or suppositories containing DHEA 0.25% to 1%, inserted vaginally once daily for 12 weeks, can reverse vaginal thinning, restore vaginal pH, and reduce pain during sexual intercourse by up to 15% when compared with placebo in patients with vaginal atrophy (21320,21429,21430,94576). A specific vaginal insert containing DHEA 0.5% (Intrarosa, Endoceutics Inc.) is an FDA approved drug used for reducing pain during sexual intercourse in patients with vaginal atrophy (94573,94576). Other clinical research shows that applying DHEA 10% cream (Diosynth) to the inner thighs daily for 12 months might improve vaginal atrophy by stimulating maturation of the vaginal epithelium in postmenopausal patients. It might also increase bone mineral density in these patients (4242).

Aging skin. Oral and topical DHEA have been evaluated for treating aging skin, with promising results. Details: Some clinical research shows that taking DHEA 50 mg daily for 12 months increases epidermal thickness, sebum production, and skin hydration, and decreases facial skin pigmentation in elderly patients (6446). Other preliminary clinical research shows that applying 1% DHEA daily for 4 months improves the appearance of paper-like skin when compared with placebo in postmenopausal patients. It also improves sebum production, skin wrinkling, and skin appearance when compared with baseline (21428).
Depression. Oral DHEA 30-500 mg daily for up to 8 weeks seems to improve symptoms of depression and dysthymia in patients with depression. Details: Canadian clinical practice guidelines recommend DHEA as a third-line treatment for depression (95691). Most clinical research shows that taking DHEA 30-500 mg daily for around 6-8 weeks improves symptoms of depression and dysthymia when compared with placebo (3270,3864,3892,4233,21404,21405). Additionally, a pooled analysis of these and 9 other clinical studies shows that DHEA can improve depressive symptoms when compared with placebo, although most of the trials evaluated in the analysis included patients without clinically diagnosed depression (104161). Other preliminary clinical research using lower doses of 5-20 mg daily over 3 weeks shows no improvement in depressive symptoms in psychotic patients (21406).
Infertility. Oral DHEA appears to improve fertility outcomes, including pregnancy and live birth rates, in females undergoing assisted reproduction. However, it is unclear if oral DHEA can reduce the risk for miscarriage after in vitro fertilization (IVF) or intra-cytoplasmic sperm injection (ICSI). Details: Meta-analyses of clinical research show that taking DHEA, typically at a dose of 75 mg daily improves fertility outcomes for females undergoing assisted reproduction (96819,96820,96821,111227). One meta-analysis limited to randomized controlled trials in patients with poor ovarian response (POR) found that taking DHEA prior to IVF or ICSI treatments increases clinical pregnancy rates by 34% and the rate of live births or ongoing pregnancy by 88% when compared with placebo or no treatment (96820,111227,113072). Additionally, meta-analyses, including both randomized controlled trials and observational research, in patients with POR or diminished ovarian reserve (DOR) undergoing IVF or ICSI show that taking DHEA 50-90 mg daily is associated with improved markers of ovarian reserve and increased oocyte yields, fertilized oocytes, top-quality embryos, and transferred embryos when compared with control groups (111227,113072). Some observational research in older females with DOR has also found that taking DHEA 30 mg three times daily for 12 weeks before IVF cycles is associated with a greater number of retrieved oocytes, improved oocyte quality, and increased cumulative pregnancy rates (103185). Inclusion of lower quality research also supports these findings (21413,21414,88493,96819,96821,99923). Additionally, in females with various conditions of compromised fertility, some preliminary clinical research shows that taking DHEA 50-75 mg daily for at least 4 months may aid with natural conception, insemination-induced conception, and IVF pregnancy outcomes (21362). However, not all evidence shows that DHEA supplementation is beneficial for infertility (21415,88726,90304,111226). In one meta-analysis, DHEA supplementation was not linked to improvements in live birth rates (111227) In another meta-analysis, the benefits such as increased clinical pregnancy rates, live birth rates, oocyte yields, and number of embryos transferred dissipated upon subgroup analysis limited to higher quality randomized controlled trials (113072). Furthermore, a large clinical study shows that pretreatment with DHEA in infertile females with POR prior to IVF and embryo transfer does not improve the number of retrieved oocytes and the rates of clinical pregnancy, pregnancy loss, and cumulative live births when compared with placebo (111226). Observational research in older patients with DOR suggests that DHEA supplementation is not linked to improved clinical pregnancy or live birth rates when compared with a control group (103185). Other clinical research in females with primary ovarian insufficiency shows that taking DHEA 75 mg daily for 16 weeks might not improve follicle size when compared with placebo (21364). The effect of DHEA pretreatment on miscarriage rates after IVF or ICSI is not clear. One meta-analysis of randomized clinical research does not support the use of DHEA pretreatment for preventing miscarriage (96820). However, another meta-analysis and lower quality research suggests that DHEA supplementation reduces the risk of miscarriage by up to 50% (21418,96819,113072).

Aging. Oral DHEA, taken for up to 2 years, does not appear to improve bone health, quality of life, or sexual function in older adults. Details: Clinical research shows that DHEA, taken as 75 mg daily in males or 50 mg daily in females, for 2 years does not seem to improve body composition, bone mineral density (BMD), insulin sensitivity, or quality of life in people aged 60 years or older who have low DHEA-S levels (15027). Additionally, a pooled analysis of clinical trials shows that taking DHEA 50-1600 mg daily for up to 2 years does not improve body composition, bone health, sexual function, lipid and glycemic parameters, or quality of life in elderly males (88434).
Muscle strength. Oral DHEA does not seem to improve muscle strength in adults. Details: While some clinical research shows that adults who take DHEA have increased muscle strength when measured by grip strength, leg press, chest press, and other measures, most clinical evidence shows that DHEA provides no benefit to muscle strength in younger and older adults (1365,10406,17617,21392,21419,21420,21421,47198).
Physical performance. Oral DHEA does not seem to improve physical performance in elderly patients. Details: Most clinical research and a meta-analysis show that older adults who take DHEA do not have increased physical function or performance as measured by oxygen uptake, duration of exercise, balance, and ability to rise from a chair (17617,21420,21421). However, one clinical study shows that taking DHEA 50 mg daily for 6 months improves lower body strength and function by a small amount when compared with placebo in elderly frail females (21392). More research is needed to determine if DHEA is beneficial in specific populations.

LIKELY INEFFECTIVE

Cognitive function. Oral DHEA does not improve cognitive function or prevent cognitive decline in most populations. Details: In the majority of clinical research, taking DHEA orally does not seem to improve cognitive function or decrease cognitive decline in healthy people over the age of 50 (3893,11334,14862,21333,21445), in peri- or post-menopausal women (6011,21397,21445), in patients with HIV (47435), or in young healthy adults when given as an acute dose (21399). However, preliminary clinical research shows that taking DHEA 50 mg daily for 4 weeks may improve certain measures of visual spatial performance and memory when compared with placebo in middle aged and elderly females (21396,21398).
Sjogren syndrome. Oral DHEA does not appear to improve symptoms with this condition. Details: Clinical research shows that taking DHEA 50-200 mg daily for 4-12 months does not benefit symptoms of primary Sjogren syndrome when compared with placebo (21354,21358,21363,21365).

Addison disease. It is unclear if oral DHEA is beneficial in patients with this condition. Details: Some preliminary clinical research shows that taking DHEA up to 50 mg daily for up to 12 months improves symptoms of Addison disease, including reversing the loss of bone mineral density (BMD) and lean mass, but without improving cognitive function (8595,21387). However, taking DHEA 50 mg daily for 12 weeks does not appear to improve cognitive or sexual function, body composition, or BMD, although it may improve mood and fatigue (7614,21330,21356).
Adrenal insufficiency. It is unclear if oral DHEA is beneficial in patients with primary or secondary adrenal insufficiency. Details: Some clinical research shows that taking low-dose DHEA, 20-50 mg daily, improves feelings of well-being, skin and hair, pubic hair growth, and sexuality in females with adrenal insufficiency or androgen deficiency due to hypopituitarism (3231,8593,17218,21317,21370,21385). However, other clinical research shows that taking low-dose DHEA for 3-12 months has little to no effect on quality of life, body composition, physical performance, cardiac function, depression, anxiety, and sexual arousal in patients with primary or secondary adrenal insufficiency (17218,21351,21357,21360,21386,21388,21389). Also, there is contradictory evidence about the effects of DHEA on plasma lipid levels in patients with adrenal insufficiency (21348,21351).
Athletic performance. It is unclear if oral DHEA can improve sprint performance. Details: Preliminary clinical research in female recreationally trained athletes shows that taking DHEA 100 mg daily for 4 weeks does not improve sprint performance when compared with placebo (99925).
Cardiovascular disease (CVD). Observational research has found that low DHEA levels are linked to a greater risk for CVD, but it is unclear if supplementation with oral DHEA is beneficial. Details: A meta-analysis of population research shows that patients with CVD and lower blood levels of DHEA-S have a worse overall prognosis when compared with patients with higher levels. Patients with the lowest levels have a 47% increased risk of future mortality events, including a 58% increased risk of fatal cardiovascular events. There was also a 42% increased risk of nonfatal cardiovascular events (96817). In elderly males, population research also shows that low serum levels of DHEA and DHEA-S are associated with an increased risk of coronary heart disease (CHD) but not cerebrovascular disease (90303).
Cervical dysplasia. It is unclear if intravaginal DHEA is beneficial in patients with cervical dysplasia. Details: Preliminary clinical research shows that DHEA 150 mg intravaginally for up to 6 months reverses dysplasia in 83% of treated females with low-grade cervical dysplasia when compared to baseline (21426). The validity of these findings is limited by the lack of a comparator group.
Chronic fatigue syndrome (CFS). It is unclear if oral DHEA is beneficial in patients with CFS. Details: Preliminary clinical research shows that oral DHEA 25-100 mg daily for 6 months improves symptoms of CFS by 8.5% to 26% when compared to baseline (7559). The validity of these findings is limited by the lack of a comparator group.
Chronic obstructive pulmonary disease (COPD). It is unclear if oral DHEA is beneficial in patients with COPD. Details: A small clinical study shows that taking DHEA 200 mg daily for 3 months increases walking distance and improves lung function in patients with COPD when compared to baseline (21395). The validity of these findings is limited by the lack of a comparator group.
Cocaine dependence. It is unclear if oral DHEA is beneficial for reducing cocaine cravings. Details: A small clinical study shows that taking DHEA 100 mg daily for 12 weeks, in addition to cognitive-behavioral group counseling, does not reduce cocaine craving when compared with counseling alone in cocaine-dependent participants (21411).
Crohn disease. It is unclear if oral DHEA is beneficial for inducing Crohn disease remission. Details: A small clinical study shows that taking DHEA 200 mg daily for 8 weeks reduces symptoms in some patients with Crohn disease when compared to baseline. Remission occurred in 6 of 7 Crohn patients (21416). The validity of these findings is limited by the small study size and lack of a comparator group.
Diabetes. Although there has been interest in using oral DHEA for diabetes, there is insufficient reliable information available about the clinical effects of DHEA for this purpose.
Erectile dysfunction (ED). It is unclear if oral DHEA is beneficial in patients with ED. Details: Preliminary clinical research shows that taking DHEA orally for 24 weeks improves erectile function, orgasmic function, sexual desire, and overall sexual satisfaction in patients with ED. DHEA seems to be beneficial for idiopathic ED or ED secondary to hypertension, but doesn't seem to provide benefit for ED related to diabetes or neurological disorders (793,8596).
Exercise-induced muscle damage. It is unclear if oral DHEA is beneficial for reducing muscle damage from exercise. Details: Preliminary clinical research shows that taking DHEA 50 mg twice daily for 5 days improves delayed-onset muscle soreness and reduces post-training blood creatinine kinase levels when compared with placebo in young males completing a 5-day exercise training program (88375).
Fibromyalgia. It is unclear if oral DHEA is beneficial for improving fibromyalgia symptoms. Details: Preliminary clinical research shows that taking DHEA 50 mg daily for 3 months does not reduce fibromyalgia symptoms when compared with placebo in postmenopausal patients with fibromyalgia (21355).
HIV/AIDS. Small clinical studies suggest that oral DHEA may improve mental health and quality of life in patients with HIV/AIDS, but DHEA does not seem to improve CD4 counts or body composition. Details: Population research shows that levels of DHEA seem to be lower in patients with more severe HIV/AIDS, suggesting that DHEA could be a marker for disease severity. Some evidence suggests that lower DHEA levels are associated with an increased risk of disease progression and AIDS (8598,14278,14279). Some clinical research shows that taking DHEA 50-500 mg daily for 2-4 months might improve mental health and quality of life when compared with placebo (3864,8598,14277,21390). However, taking DHEA in doses up to 2.25 grams daily does not appear to improve CD4 counts, muscle mass, or bone mass when compared with placebo (3865,14277,21390).
Menopausal symptoms. Oral DHEA might reduce hot flashes and intravaginal DHEA might improve vaginal atrophy and sexual activity; however, oral DHEA does not seem to improve psychological symptoms associated with menopause. Details: Some research shows that taking DHEA 10-25 mg daily for 12 months improves subjective vasomotor symptoms such as hot flashes, as well as psychological symptoms and sexuality (11464,21417). Also, administering a daily ovule containing DHEA (Vaginorm, Recipharm) 3.5-13 mg intravaginally for 12 weeks appears to reverse vaginal atrophy and improve sexual activity in postmenopausal patients with vaginal atrophy (21442). However, other clinical research shows that taking DHEA 50 mg daily for up to 26 weeks does not improve mood, fatigue, cognition, sexual function, or sense of well-being in post- or peri-menopausal patients when compared with placebo (6011,21361). Additionally, a pooled analysis of clinical research shows that DHEA taken orally does not improve psychological symptoms related to menopause (88492).
Metabolic syndrome. It is unclear if oral DHEA is beneficial for reducing risk for metabolic syndrome. Details: Preliminary clinical research shows that taking DHEA 50 mg daily for 6 months or 100 mg daily for 3 months decreases weight, abdominal fat, and blood pressure and reduces cholesterol, glucose, and insulin levels when compared with placebo in overweight elderly patients (12215,21350).
Muscular dystrophy. It is unclear if oral DHEA is beneficial in patients with myotonic dystrophy type I. Details: Taking DHEA 100 or 400 mg daily for 12 weeks might not affect muscle strength in patients with myotonic dystrophy type I when compared with placebo (21334). However, intravenous DHEA-S 200 mg daily for 8 weeks appears to improve daily function, muscle strength, and heart function compared with baseline (21434). The validity of this finding is limited by the lack of a control group.
Obesity. It is unclear if oral DHEA is beneficial for reducing body weight in patients who are obese or overweight. Details: Preliminary clinical research shows that taking DHEA 40 mg sublingually twice daily for 8 weeks, or 1600 mg by mouth for 28 days, does not affect body weight or body composition when compared with placebo in obese adults (21410,21427). Also, preliminary clinical research shows that taking DHEA 50-100 mg daily for 3-12 months does not affect central adiposity in older individuals when compared with placebo (21349).
Opioid withdrawal. It is unclear if oral DHEA is beneficial in patients with heroin withdrawal. Details: Preliminary clinical research shows that taking DHEA 100 mg daily as adjunct to standard therapy for 12 months does not improve drug withdrawal symptoms in heroin addicts when compared with standard therapy alone (21412).
Osteoporosis. It is unclear if oral DHEA is beneficial in patients with osteoporosis; any benefit may depend on individual patient characteristics. Details: There is contradictory evidence about the effectiveness of DHEA 50-100 mg daily for improved bone mineral density (BMD) in older adults with osteoporosis or osteopenia (12563,12564,21392), as well as the effectiveness of DHEA for improved BMD in females with anorexia nervosa (12562,21393). One pooled analysis shows that DHEA does not improve BMD in postmenopausal patients (88492), while another shows that DHEA can increase hip BMD in healthy older females, but not males (103186). The reason for these discrepant findings is unclear, but may relate to different patient populations, durations of therapy, and DHEA doses assessed in the included studies. Additionally, most of the studies included in these analyses were of low quality and inadequate statistical power.
Parkinson disease. Although there has been interest in using oral DHEA for Parkinson disease, there is insufficient reliable information available about the clinical effects of DHEA for this purpose.
Partial androgen deficiency. It is unclear if oral DHEA is beneficial for symptom improvement in patients with this condition. Details: Preliminary clinical research shows that taking DHEA 25 mg daily for one year might clinically improve mood, fatigue, and joint pain in older males with partial androgen deficiency when compared to baseline (21331). Other preliminary clinical research shows that taking DHEA 50 mg twice daily for 4 months does not improve erectile or sexual function when compared with placebo in hypoandrogenic males (21424).
Parturition. Intravenous DHEA before the onset of labor may shorten the time to labor onset and shorten labor duration. Details: Clinical research shows that intravenous DHEA-S 100 mg daily for 3 days, or given twice weekly until the onset of labor starting after 38 weeks of gestation, increases cervical ripening and shortens the time to onset of labor and the duration of labor when compared with a control in nulliparous women (21384,21431). Also, intravenous DHEA 50-200 mg given multiple times until the onset of labor starting after 37 weeks of gestation appears to shorten the time to delivery in primiparous and multiparous women (21432,21433). It is unclear if oral DHEA is beneficial for this purpose.
Rheumatoid arthritis (RA). It is unclear if oral DHEA is beneficial in patients with RA. Details: Preliminary clinical research shows that taking oral DHEA 200 mg for 16 weeks does not reduce symptoms of RA in elderly patients (21422). However, other clinical research in a small number of premenopausal females with RA shows that taking DHEA 50 mg daily for 12 weeks improves quality of life, but not disease activity, when compared with placebo (104159).
Schizophrenia. It is unclear if oral DHEA is beneficial in patients with schizophrenia. Details: Some research shows that taking DHEA orally improves both negative and positive symptoms in patients with schizophrenia. It may be more effective in females (9692). However, other clinical research shows no benefit (21423).
Sexual dysfunction. It is unclear if oral or intravaginal DHEA is beneficial for improving sexual dysfunction in males or females. Details: DHEA may be modestly beneficial in some postmenopausal patients with decreased libido or dyspareunia. Preliminary clinical research shows that taking DHEA 50-100 mg daily, or a single dose of DHEA 300 mg, improves sexual desire when compared to baseline (9906,21443). Additional clinical research shows that use of intravaginal DHEA (Vaginorm, Recipharm) at concentrations of 0.25% to 1% daily for 12 weeks might improve sexual function when compared with placebo (47361). However, a pooled analysis shows that DHEA is not associated with improvements in libido or sexual function (88414,88492). DHEA has also been evaluated in other patient populations. Small clinical studies show that taking DHEA doesn't seem to influence response to sexual stimuli in sexually functional premenopausal women (8594) or improve libido in individuals age 40-70 years (21449). Preliminary clinical research in males with hypoactive sexual desire disorder (HSDD) shows that taking DHEA 50 mg twice daily for 6 weeks does not improve erectile or sexual function when compared with placebo (88414). In adults with midlife-onset or HIV-associated depression, preliminary clinical research shows that taking DHEA 90-500 mg daily for 3-8 weeks may improve sexual function and libido when compared with placebo (3864,21405).
Systemic lupus erythematosus (SLE). Most small clinical studies suggest that oral DHEA may modestly improve symptoms in patients with SLE, but some conflicting research exists. Details: Some clinical research shows that taking DHEA has little to no effect on disease activity in patients with mild to moderate SLE (21425,21447). However, small clinical studies and a meta-analysis of these studies show that taking DHEA in conjunction with conventional treatment may help improve frequency of flare-ups, muscle ache, oral ulcers, and quality of life, reduce corticosteroid doses needed (2113,2114,2136,6068,6447,12561,12574,21346,21447), and improve bone mineral density (6068,6097,6447,21394).
Ulcerative colitis. It is unclear if oral DHEA is beneficial for inducing ulcerative colitis remission. Details: A small clinical study shows that taking DHEA 200 mg daily for 8 weeks reduces symptoms of ulcerative colitis when compared to baseline in some patients with ulcerative colitis. Remission occurred in 6 of 13 ulcerative colitis patients (21416). The validity of these findings is limited by the small study size and the lack of a comparator group. More evidence is needed to rate DHEA for these uses.

LIKELY EFFECTIVE

Coronary heart disease (CHD). A diet high in soluble fiber, such as that found in oats, reduces the risk of CHD. Details: Clinical research shows that a diet containing foods high in fiber, such as oats, oat bran, or whole oat flour, reduces the risk of CHD (2737,4960,4962,4963,4964,4965,4966,4967,4968). In 1993, the US Food and Drug Administration (FDA) approved a health claim stating that consuming at least 3 grams of soluble fiber per day, as part of a diet low in saturated fat and cholesterol, may reduce the risk of CHD (102336). However, clinical studies show that at least 3.6 grams of soluble fiber daily is needed to reduce the risk of CHD (5786,5787,5788,5794,5795,5796).
Dyslipidemia. A diet rich in soluble fiber, such as that found in oats, can reduce cholesterol by a moderate amount. Details: Oats, oat bran, and other soluble fibers can modestly reduce total and low-density lipoprotein (LDL) cholesterol, especially when consumed as part of a diet low in saturated fat. Consuming 56-150 grams of whole oat products such as oatmeal and oat bran, containing 3.6-10 grams of soluble fiber daily, can significantly lower total and LDL cholesterol levels. For each gram of soluble fiber consumed, total cholesterol decreases by about 1.4 mg/dL and LDL by about 1.2 mg/dL. Eating 3-10 grams of soluble fiber daily can reduce total cholesterol by about 4-14 mg/dL (4976,4977,5786,5788,5792,5794,5795,8521,107749,113488,113495). For example, eating 3 bowls of oatmeal (28 gram servings) daily, providing a total of 3 grams of soluble fiber daily, can decrease total cholesterol by about 5 mg/dL (5788). However, consuming more than 10 grams of soluble fiber daily doesn't seem to increase effectiveness (5788). A meta-analysis comparing the effects of oats and isolated beta-glucans shows that both products similarly impact lipid profiles, suggesting that the bioactive component of oats are beta-glucans (113488). Oat bran products, such as oat bran muffins and oat bran flakes, may vary in their ability to lower cholesterol, depending on the total soluble fiber content and other dietary variables (6188). Whole oat products might be more effective for lowering LDL and total cholesterol than foods containing oat bran plus soluble fiber (10145). Although oats are shown to lower total and LDL cholesterol, a meta-analysis and a small clinical study in adults with and without dyslipidemia shows that consuming oatmeal or oat products does not reduce triglycerides or increase high-density lipoprotein (HDL) cholesterol when compared with controls (113488,113495).

Diabetes. A diet rich in whole grains, such as oats, may help prevent diabetes or improve blood glucose control in patients with type 1, type 2, or gestational diabetes. Details: Population research shows that for every 16 gram daily serving of whole grains, including oats, there is a 7% to 11% lower risk of developing type 2 diabetes (100622). There is also evidence that consuming oats can decrease blood glucose and insulin levels, as well as lipid levels, in patients with diabetes. The glycemic effects of oats depend on the level of processing of the oat products. Consuming intact oat kernels or thick-cut oats (>0.6 mm) reduces postprandial blood glucose and insulin, but consuming thin-cut, or "quick", oats has no effect (105536). Clinical research shows that consuming oats and oat bran for 4-8 weeks decreases pre-prandial blood glucose, 24-hour plasma glucose, glycated hemoglobin (HbA1c), insulin levels, and low-density lipoprotein (LDL) cholesterol in people with type 2 diabetes (4980,4982,6266,103345). Various doses have been used, including 3 grams of soluble fiber daily, or bread providing 34 grams of total fiber daily (9 grams of soluble fiber) (4961,4980). Additional clinical research in obese adults with type 2 diabetes shows that eating whole grain oats 50-100 grams daily in place of other carbohydrates reduces postprandial blood glucose by 19-27 mg/dL when compared with other carbohydrates in a healthy diet. After 1 year, the groups consuming 50 grams and 100 grams of oats had an additional 0.48% and 0.64% reduction in HbA1c, respectively, when compared with the regular healthy diet group (97520). There is also some evidence that consuming oats 50 grams daily, containing 25 grams of soluble fiber, might be more effective for improving glycemic control and decreasing hyperinsulinemia than the standard moderate fiber diet recommended by the American Diabetes Association (ADA) (6266). Oats have also been evaluated in adolescents with type 1 diabetes. One very small clinical study shows that taking 50 grams of a specific oat product (Betaglucare), providing beta-glucans 6 grams, in three divided doses daily for one week is beneficial for glycemic control and variability when compared with a standard diet without beta-glucans or with taking only 25 grams of the product daily. Maximal, mean, and pre- and post-meal blood glucose levels were modestly lower, and minimal blood glucose levels were modestly higher. Most measures of glycemic variability were statistically different, although there were no differences in the duration of hypoglycemia or hyperglycemia between groups (105261). Oats have also been evaluated in patients with gestational diabetes. A randomized, controlled trial shows that taking 30 grams of a specific oat bran product (OAB; Golden Light Cup Company) orally twice daily at lunch and dinner for 4 weeks improves mean fasting blood glucose and two-hour postprandial glucose when compared with a control group. After 4 weeks, the mean fasting blood glucose and 2-hour postprandial glucose in the treatment group were 85 mg/dL and 104 mg/dL, respectively, compared with 93 mg/dL and 117 mg/dL, respectively, in the control group (107751). The validity of this study is limited by the short treatment duration and lack of follow-up.
Gastric cancer. A diet rich in soluble fiber, such as that found in oats, might reduce the risk of gastric cancer. Details: Observational research has found that consuming a diet that includes cereal fiber, such as oats and oat bran, might reduce the incidence of gastric cancer (10435).

Colorectal cancer. Regular consumption of oats does not seem to reduce the risk of colorectal cancer. Details: Observational research has found that consuming oat bran or oats orally doesn't seem to reduce the risk of colon cancer. Additionally, consuming fiber, including oat-bran fiber, is not associated with a reduction in the risk for recurrence of colorectal adenomas (4820,5104).

Acne. Although there is interest in using topical oats for acne, there is insufficient reliable information about the clinical effects of oats for this purpose.
Anxiety. Although there is interest in using oral oats for anxiety, there is insufficient reliable information about the clinical effects of oats for this purpose.
Atopic dermatitis (eczema). Topical colloidal oatmeal cream may be beneficial in patients with atopic dermatitis. Details: Preliminary clinical research shows that applying a cream containing colloidal oatmeal 1% daily for 2 weeks moderately reduces the severity of atopic dermatitis when compared with baseline (103344). The validity of this finding is limited by the lack of a comparator group. Other research suggests that colloidal oatmeal may be beneficial when used in combination with topical steroids. Clinical research shows that the benefits obtained from applying an ointment containing fluocinolone 0.025% to the hands for 2 weeks were better maintained in the patients who also used a cream containing colloidal oatmeal 1% during this time period and for an additional 4 weeks when compared with patients using fluocinolone and the cream base without colloidal oatmeal. Quality of life was also improved in the patients using colloidal oatmeal (103340).
Breast cancer. Observational research suggests that regular oatmeal intake may be associated with reduced mortality from breast cancer. Details: Population research in postmenopausal patients has found that those who have eaten 50 grams of oatmeal daily prior to a breast cancer diagnosis have a 20% reduced risk of all-cause mortality in the 7 years following the diagnosis when compared with patients who have not eaten oatmeal. However, no benefit was seen when post-diagnostic oatmeal intakes were examined (103343).
Burns. Although there is interest in using topical oats for burns, there is insufficient reliable information about the clinical effects of oats for this purpose.
Chronic fatigue syndrome (CFS). Although there is interest in using oral oats for CFS, there is insufficient reliable information about the clinical effects of oats for this purpose.
Cognitive function. It is unclear if oral oats are beneficial in healthy adults with mild memory impairment. Details: Preliminary clinical research in healthy middle-aged adults with self-reported memory decline shows that consuming a specific wild green-oats extract (Neuravena, Frutarom) 800 mg as a single dose improves overall speed, but not overall accuracy, of cognitive performance when compared with placebo. However, a higher dose of 1600 mg was ineffective (97519).
Dry skin. It is unclear if applying lotion containing colloidal oat extract improves dry skin to a greater extent than other lotion products. Details: Preliminary clinical research shows that applying a lotion containing colloidal oat extract (Aveeno Active Naturals Skin Relief 24Hr Moisturizing Lotion, Johnson & Johnson) twice daily for 2 weeks improves itchiness, cracking, scaling, dryness, and roughness when compared to baseline in females with dry skin (91458). Additional preliminary clinical research shows that applying a colloidal oatmeal lotion to the legs twice daily for three weeks reduces skin dryness and improves skin integrity when compared to baseline in adults with dry skin (97518). The validity of these findings is limited by the lack of a comparator group.
Exercise-induced muscle soreness. It is unclear if oral oats are beneficial for exercise-induced muscle soreness. Details: A small clinical trial shows that eating two cookies containing oat flour 60 grams daily for 8 weeks reduces muscle soreness 48 or 72 hours after downhill running when compared with baseline (103341).
Fat redistribution syndrome. It is unclear if oral oats are beneficial for fat redistribution syndrome. Details: Consumption of a high fiber diet, including oats, with adequate energy and protein might prevent fat deposition in patients with HIV. A one-gram increase in total dietary fiber may decrease the risk of fat deposition by 7% (12517).
Gallbladder disease. Although there is interest in using oral oats for gallbladder disease, there is insufficient reliable information about the clinical effects of oats for this purpose.
Hypertension. It is unclear if oral oats are beneficial for hypertension. Details: A meta-analysis of 21 clinical studies in healthy adults and those with a variety of metabolic conditions including hypertension shows that consumption of oat products reduces systolic blood pressure (SBP) by 3 mmHg but has no effect on diastolic blood pressure (DBP) when compared with control. Subgroup analysis suggests that consuming oat products reduces SBP by 10 mmHg in patients with hypertension at baseline. An additional subgroup analysis suggests that consuming at least 5 grams of beta-glucan-enriched oats daily or consuming oats for a duration at least 8 weeks reduces SBP and DBP (113494). Observational research has found that consumption of oats as oatmeal or oat cereal does not seem to reduce DBPor SBP in males with minor elevations in blood pressure or patients with dyslipidemia (2956,113495). A randomized, controlled trial in patients with stage 1 hypertension receiving dietary guidance shows that taking 30 grams of oat bran, providing 8.9 grams of dietary fiber, once daily with breakfast or in between meals for 3 months improves various blood pressure measures when compared with dietary guidance alone. After 3 months of treatment, 24-hour maximum SBP and DBP decreased by 14 mmHg and 11 mmHg, respectively, and office SBP and DBP decreased by 15 mmHg and 10 mmHg, respectively. Oat consumption may also have impacted antihypertensive medication use. Two patients in the control group increased doses of antihypertensive medications, whereas 6 patients in the treatment group decreased doses and 1 patient discontinued use (107750). The effect of oral oat bran on patients with stage 2 hypertension or pre-hypertension is unknown.
Irritable bowel syndrome (IBS). Although there is interest in using oral oats for IBS, there is insufficient reliable information about the clinical effects of oats for this purpose.
Metabolic syndrome. Limited research suggests that oats may not be beneficial for metabolic syndrome. Details: Preliminary clinical research in adults with metabolic syndrome shows that adding oat bran 40 grams daily for 6 weeks to a low-calorie diet does not reduce the incidence of metabolic syndrome. Oat bran also does not improve body weight, blood pressure, low-density lipoprotein (LDL) cholesterol, triglycerides, or blood glucose levels when compared with a low-calorie diet alone in patients with metabolic syndrome (103342).
Osteoarthritis. Although there is interest in using oral oats for osteoarthritis, there is insufficient reliable information about the clinical effects of oats for this condition.
Pruritus. Applying oat lotion topically may improve some types of pruritus. Details: Preliminary clinical research shows that applying an oat lotion (Espanol) twice daily for up to 2 weeks can decrease itching intensity by about 20% when compared to baseline in patients with pruritus associated with chronic kidney disease (uremic pruritus). This decrease is similar to the effects of applying vinegar 5% solution or taking hydroxyzine 10 mg orally. However, applying the oat lotion does not appear to decrease the frequency of itching (91457).
Psoriasis. Although there is interest in using topical oats for psoriasis, there is insufficient reliable information about the clinical effects of oats for this purpose.
Rheumatoid arthritis (RA). Although there is interest in using oral oats for RA, there is insufficient reliable information about the clinical effects of oats for this purpose.
Stroke. It is unclear if oral oats are beneficial for reducing the risk of stroke. Details: Population research suggests that consuming oatmeal for breakfast once weekly might reduce the incidence of stroke by a small amount when compared with consuming white bread or eggs for breakfast (103337).
Ulcerative colitis. Oral oats have only been evaluated in combination with other ingredients; their effect when used alone is unclear. Details: Preliminary clinical research shows that taking a specific oat-based product (Profermin, Nordisk Rebalance) containing fermented oat flour, Lactobacillus plantarum, barley malt flour, and lecithin, 250 mL orally twice daily for 8 weeks, reduces disease activity and increases remission in about two-fold more patients with relapsing ulcerative colitis, when compared with treatment with a specific nutritional beverage (Fresubin Original, Fresenius Kabi) (90271).
Wound healing. Although there is interest in using topical oats for wound healing, there is insufficient reliable information about the clinical effects of oats for this purpose. More evidence is needed to rate oats for these uses.

SARSAPARILLA

Cancer. Although there has been interest in using oral sarsaparilla for cancer, there is insufficient reliable information about the clinical effects of sarsaparilla for this purpose.
Psoriasis. Although there has been interest in using oral sarsaparilla for psoriasis, there is insufficient reliable information about the clinical effects of sarsaparilla for this purpose.
Rheumatoid arthritis (RA). Although there has been interest in using oral sarsaparilla for RA, there is insufficient reliable information about the clinical effects of sarsaparilla for this purpose. More evidence is needed to rate sarsaparilla for these uses.

SAW PALMETTO

Transurethral resection of the prostate (TURP). Saw palmetto 320 mg daily seems to improve outcomes after TURP surgery in a dose-dependent manner. Details: Clinical research shows that taking saw palmetto (Permixon, Pierre Fabre Medicament) 320 mg daily for 2 months prior to TURP surgery reduces blood loss, the duration of surgery, the development of intraoperative complications, the duration of catheterization, and the length of hospitalization when compared with placebo (73323,73353). Although these studies found benefit, a small study using a lower dose of saw palmetto (Prostagood Mono, Abdi Ibrahim) 160 mg orally once daily for 5 weeks prior to TURP did not find any decrease in the risk of perioperative hemorrhage, or the density of prostate tissue (17202).

Benign prostatic hyperplasia (BPH). Although individual study results are conflicting, the overall body of evidence suggests that saw palmetto does not offer clinically meaningful improvements in BPH-related symptoms. Details: Research on the use of saw palmetto for improving symptoms of BPH is inconsistent and contradictory. To date, the best available evidence addressing the effectiveness of saw palmetto in patients with BPH comes from two high-quality clinical trials sponsored by the National Institutes of Health (NIH). In one of these trials, saw palmetto 160 mg twice daily for one year was ineffective for reducing moderate to severe symptoms of BPH when compared with placebo (14274). In the other trial, taking saw palmetto 320-960 mg daily for 72 weeks did not significantly improve symptoms when compared with placebo (17684). Additionally, meta-analyses of these trials and many of the small trials described below show that taking saw palmetto does not improve BPH-related signs and symptoms or International Prostate Symptom Scores (IPSS) (89441,102835,112804). While several small, low-quality clinical trials and observational studies in patients with BPH suggest that saw palmetto provides some improvement in urinary symptoms, nocturia, urinary flow, and/or residual urine volume when compared with placebo or baseline (6750,6764,6772,73315,73383,73385,73387,89441,96570,110541), other studies show that saw palmetto has no clinically meaningful effect on BPH-related signs and symptoms, including prostate volume (5093,6752,11314,73343,96409). The validity of several of these studies is limited due to the use of per-protocol analyses and/or a lack of placebo control groups. Beyond this, reasons for these discrepant findings are unclear; however, the mixed results may be due to use of different saw palmetto products, varying study methodologies, different patient populations, and varying symptom scoring tools. Additionally, research shows significant variation in the chemical composition of commercially available saw palmetto extracts (17305,89441). Several clinical trials have compared saw palmetto to 5-alpha reductase inhibitors such as finasteride (Proscar) or dutasteride (Avodart). Some small studies suggest that it may be comparable to these medications for relieving BPH symptoms, but with less effect on prostate size or prostate-specific antigen (PSA) levels (6424,96570). It may also be better tolerated, with a positive effect on sexual dysfunction (6424,6763,18215,89441). Additionally, one observational study in patients with BPH has found that taking saw palmetto 320 mg with tamsulosin 0.4 mg daily for 6 months is associated with similar improvements in IPSS and quality of life scores, but also has a lower risk of reduced libido, when compared with tamsulosin plus dutasteride 5 mg or finasteride 0.5 mg daily (110542). Some research has also compared saw palmetto to alpha-adrenergic blockers. Alpha-adrenergic blockers appear to have a faster onset of symptom relief (2732,6750), and saw palmetto might be less effective than the alpha-adrenergic blocker prazosin (Minipress). Although some studies and a meta-analysis suggest it is similarly effective to tamsulosin (Flomax) after 6-12 months of treatment for improving various symptoms of BPH (6775,6776,11243,89441,96570,104804,107483), another meta-analysis found that alpha-blockers were more effective than saw palmetto for these outcomes (102835). Additionally, tamsulosin appears to be more effective than saw palmetto for reducing prostate volume (104802). However, some research suggests that saw palmetto may be better tolerated than tamsulosin (107483). It is unclear if taking saw palmetto with tamsulosin can improve BPH symptoms. Several low-quality studies and a meta-analysis of two of these studies show no additional benefit over using tamsulosin alone (8901,89443,89448,96410). However, one study suggests that a specific saw palmetto extract (Permixon, Pierre Fabre Medicament) 320 mg daily is associated with a 29% decrease in the IPSS when taken alone, compared with a 37% decrease when taken along with tamsulosin 0.4 mg daily for 6 months. Tamsulosin alone was associated with a 31% decrease (104802). Saw palmetto has also been evaluated in combination with other ingredients. A meta-analysis of 8 clinical studies in adults with lower urinary tract symptoms due to BPH shows that taking saw palmetto in combination with other herbal ingredients does not improve urologic symptoms of BPH when compared with placebo or no intervention (112804). However, small, low-quality studies of various combinations of saw palmetto with other ingredients have demonstrated some benefit for improving symptoms of BPH, and some have shown equivalence to finasteride, tamsulosin, or tadalafil (Cialis). These ingredients include stinging nettle root (PRO 160/120, Dr. Willmar Schwabe Pharmaceuticals) (6763,17307,73330,89441); cernitin, beta-sitosterol, and vitamin E (11241); selenium and lycopene (Profluss, Konpharma) (90354,97255); pygeum, lycopene, Epilobium parviflorum, and pumpkin seed oil (ProstateEZE Max, Caruso's Natural Health) (92164); and quercetin and beta-sitosterol (Difaprost, Difass International) (96784). Additionally, one study suggests that an enriched form of saw palmetto oil containing 3% beta-sitosterol seems to be more effective than standard saw palmetto oil containing 0.3% beta-sitosterol in reducing IPSS scores (104803).

Androgenic alopecia. It is unclear if oral or topical saw palmetto is beneficial in patients with androgenic alopecia. Details: A small clinical study in males and females with androgenic alopecia shows that taking a specific saw palmetto oil (VISPO, Vidya Herbs) 100 mg daily for 16 weeks reduces hair fall and increases hair density but does not improve hair thickness, anagen-telogen ratio, or most subjective measures of hair growth when compared with placebo (112805). Other clinical research shows that taking saw palmetto extract 320 mg daily for 24 months is less effective for improving hair growth in males with androgenic alopecia when compared with finasteride 1 mg daily (89444). Topical saw palmetto has also been investigated for treating androgenic alopecia. Some clinical research shows that saw palmetto lotion, applied twice daily for 50 weeks, improves hair density by 27% in individuals with androgenic alopecia. However, a 13% improvement was observed in the placebo group, and no between-group comparisons were made (73435). Another small clinical study in male and females with mild to moderate androgenic alopecia shows that applying 5 mL of a lotion containing saw palmetto oil 20% (VISPO, Vidya Herbs) to the scalp for 30 minutes daily for 16 weeks reduces hair fall and increases hair density but does not improve hair thickness, anagen-telogen ratio, or subjective measures of hair growth when compared with placebo (112805). Saw palmetto has also been evaluated in combination with other ingredients. A very small clinical study in males with androgenic alopecia shows that taking a combination of saw palmetto extract 200 mg plus beta-sitosterol 50 mg twice daily for 18-24 months improves subjective scores of hair quantity and quality when compared with placebo (15550). Another small clinical study in males with androgenic alopecia receiving platelet-rich plasma every 3 weeks shows that applying 1 mL of topical saw palmetto, redensyl, and biotin daily for 12 weeks modestly improves subjective hair loss scores and photographic assessment of hair growth when compared with 1 mL of topical Procapil daily (112176). However, it is unclear if these effects are due to saw palmetto, other ingredients, or the combination.
Asthma. Although there has been interest in using oral saw palmetto for asthma, there is insufficient reliable information about the clinical effects of saw palmetto for this purpose.
Chronic bronchitis. Although there has been interest in using oral saw palmetto for chronic bronchitis, there is insufficient reliable information about the clinical effects of saw palmetto for this purpose.
Chronic prostatitis and chronic pelvic pain syndrome (CP/CPPS). It is unclear if oral saw palmetto is beneficial in patients with CP/CPPS. Details: Preliminary clinical research shows that oral saw palmetto 325 mg daily for one year does not significantly improve symptoms of CP/CPPS when compared with finasteride 5 mg once daily (11354). However, a clinical trial in patients with moderate to severe CP/CPPS shows that taking saw palmetto 160 mg orally twice daily for 12 weeks improves NIH Chronic Prostatitis Index (NIH-CPSI) score after two weeks of treatment in patients with moderate disease and after 4 weeks of treatment in patients with severe disease when compared with placebo. Independent of severity, 73% of patients taking saw palmetto report a 6-point reduction in NIH-CPSI total score, compared to 33% of patients taking placebo (107482). Saw palmetto extract has also been evaluated in combination with other ingredients. A preliminary clinical study shows that taking a combination of saw palmetto extract 320 mg, selenium 50 mcg, and lycopene oil extract 5 mg daily for 8 weeks improves symptoms and peak flow in patients with CP/CPPS when compared with baseline. However, these effects were not observed or were less significant in patients treated with saw palmetto alone (60442).
Common cold. Although there has been interest in using oral saw palmetto for the common cold, there is insufficient reliable information about the clinical effects of saw palmetto for this purpose.
Hirsutism. Although there has been interest in using oral and topical saw palmetto for hirsutism, there is insufficient reliable information about the clinical effects of saw palmetto for this purpose.
Non-neurogenic lower urinary tract symptoms (LUTS). It is unclear if oral saw palmetto is beneficial in females with non-neurogenic LUTS. Details: A small clinical study in elderly Japanese females with LUTS shows that taking saw palmetto extract 320 mg daily for 12 weeks reduces daytime urinary frequency and might improve nocturia, but it does not seem to reduce urinary urgency, incontinence, straining, bladder pain, or urethral pain when compared with placebo (110540).
Prostate cancer. Small preliminary studies suggest that saw palmetto does not reduce prostate cancer risk or symptoms associated with prostate cancer. Details: Population research shows that people who take saw palmetto supplements do not have a lower risk of developing prostate cancer (15217). Preliminary clinical research also shows that taking saw palmetto 960 mg daily before, during, and after radiation treatment for early prostate cancer does not significantly improve lower urinary tract symptoms when compared with placebo (96412).
Prostatitis. Adding saw palmetto to antibiotic therapy seems to relieve some symptoms of bacterial prostatitis more effectively than antibiotics alone. Details: Preliminary clinical research in patients with bacterial prostatitis shows that taking saw palmetto extract daily for eight weeks, with prulifloxacin 600 mg daily for 15 days, reduces pain and urinary symptoms more than prulifloxacin alone, but the combination does not appear to improve bacterial eradication or sexual dysfunction more than the antibiotic alone (89442). One small clinical study in patients with chronic nonbacterial prostatitis shows that a specific saw palmetto extract (Prostamol Uno, Profluss) 320 mg daily improves symptoms when compared with no treatment (73329). Combinations of saw palmetto with other supplements have also been used with fluoroquinolone antibiotics, typically resulting in symptom improvement when compared with the antibiotic alone. These supplement combinations include saw palmetto, indole-3-carbinol, and epigallocatexin-3-gallate (Indigal Plus) 2 capsules twice daily for 3 months (73355); saw palmetto 160 mg, stinging nettle 120 mg, curcumin 200 mg, and quercetin 100mg (ProstaMEV plus FlogMEV) for 2 weeks (73346); and saw palmetto 320 mg, Bacillus coagulans 200 mg, and arbutin 100 mg (Lactorepens) daily for 30 days (96411).
Sexual desire. Although there has been interest in using oral saw palmetto for sexual desire, there is insufficient reliable information about the clinical effects of saw palmetto for this purpose.
Sexual dysfunction. Although there has been interest in using oral saw palmetto for sexual dysfunction, there is insufficient reliable information about the clinical effects of saw palmetto for this purpose. More evidence is needed to rate saw palmetto for these uses.

Diabetes. Oral stinging nettle seems to improve glycemic control in patients with diabetes. Details: A meta-analysis of 8 small heterogeneous clinical trials in adults with type 2 diabetes shows that taking stinging nettle 1.5-10 grams in divided doses daily for 8-12 weeks reduces fasting blood glucose (FBG) by 18 mg/dL when compared with placebo (102865). Glycated hemoglobin (HbA1c) was not improved, but the study durations were not adequate to detect an improvement in this measure. Despite positive results on FBG, taking stinging nettle does not seem to improve insulin secretion or measures of insulin sensitivity (91519,102865,108903). Another meta-analysis of 3 small clinical studies in adults with type 2 diabetes shows that taking stinging nettle reduces HbA1c by about 1.3% when compared with placebo. This analysis also suggests stinging nettle reduces post-prandial blood glucose by about 114 mg/dL; however, this is based on a single study. Stinging nettle did not improve fasting blood glucose or insulin resistance in this analysis (111503). The validity of these findings is limited by the low quality and heterogeneity of included studies, as well as unclear dosing. Furthermore, since most research has been conducted in Iran, it is unknown if these findings are generalizable to other geographic locations. Stinging nettle has also been used in combination with other natural medicines. One small clinical study in adults with type 2 diabetes shows that taking a product containing stinging nettle leaf extract 200 mg, milk thistle 200 mg, and Boswellia serrata gum 200 mg three times daily for 3 months reduces FBP by about 28 mg/dL and HbA1c by about 1.5%, compared with a smaller reduction in the placebo group (96742). It is unclear if this effect is due to stinging nettle, the other ingredients, or the combination.

Allergic rhinitis (hay fever). It is unclear if oral stinging nettle is beneficial for hay fever. Details: Taking stinging nettle leaf extract 300 mg 3-7 times daily at the first sign of hay fever symptoms seems to provide subjective improvement (7035). However, adding stinging nettle to conventional allergy medication might not provide any additional benefit. One small clinical study shows that adding stinging nettle tablets (Urtidin, Barij Essence Pharmaceutical Co.) 150 mg four times daily for 1 month to treatment with loratadine and nasal saline rinses does not improve symptoms of allergic rhinitis when compared with placebo with loratadine and nasal saline rinses (96743).
Anemia. Although there is interest in using oral stinging nettle for anemia, there is insufficient reliable information about the clinical effects of stinging nettle for this condition.
Asthma. Although there is interest in using oral stinging nettle for asthma, there is insufficient reliable information about the clinical effects of stinging nettle for this condition.
Benign prostatic hyperplasia (BPH). It is unclear if oral stinging nettle is beneficial for BPH. Details: A meta-analysis of clinical research, including 5 clinical studies and 1,128 patients with BPH, shows that taking stinging nettle root extract 360-600 mg in divided doses daily for 2-12 months improves peak urinary flow rate and symptom scores while modestly reducing prostate volume when compared with control. However, the validity of these results is limited by significant heterogeneity due to the variability in the products used and the specific endpoints investigated (96744). In the largest clinical trial in the analysis, patients took stinging nettle root extract 120 mg three times daily for 6 months (76406). Stinging nettle has also been evaluated in combination products. Clinical research in patients with BPH shows that taking a specific combination product (PRO 160/120, Dr. Willmar Schwabe Pharmaceuticals) containing a specific extract of stinging nettle root (WS 1031) 120 mg plus a specific extract of saw palmetto fruit (WS 1473) 160 mg twice daily for 24-48 weeks seems to improve urinary tract symptoms when compared with control; the effect may last at least 48 weeks after treatment (15195,15551,76409). However, taking a different combination product does not seem to be beneficial. A small clinical study in patients with BPH shows that taking a product containing stinging nettle root extract 240 mg, saw palmetto, pumpkin seed oil, lemon bioflavonoid, and beta-carotene, three times daily for 6 months, does not improve symptoms of BPH (5093).
Bleeding. Topical stinging nettle has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Some preliminary clinical research shows that applying 4 mL of a specific product (Ankaferd blood stopper, Mefar Ilaç Sanayi A.S) containing alpinia, licorice, thyme, stinging nettle, and common grape vine to the affected area reduces bleeding, but does not improve the time for episiotomy repair, when compared with using saline (31010).
Gingivitis. Stinging nettle in a mouthwash solution has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in patients with moderate gingival inflammation suggests that using 10 mL of mouthwash solution containing a 1:1:1 mixture of stinging nettle, juniper, and yarrow twice daily for 3 months does not reduce plaque or bleeding when compared with control (76443). It is not clear if this effect is due to stinging nettle, the other ingredients, or the combination.
Gout. Although there is interest in using oral stinging nettle for gout, there is insufficient reliable information about the clinical effects of stinging nettle for this condition.
Gulf war syndrome. It is unclear if oral stinging nettle is beneficial for Gulf war syndrome. Details: A very small exploratory clinical trial in males with Gulf war syndrome shows that taking stinging nettle leaf (Nature's Way) 1305 mg in two divided doses daily for 30 days modestly improves symptom severity when compared with placebo (108311). The clinical relevance of this finding is limited by the use of an unvalidated scoring scale. Additionally, it appears that most patients had mild, unspecified symptoms at baseline; it is unclear if stinging nettle is beneficial for moderate to severe symptoms.
Hyperandrogenism. It is unclear if oral stinging nettle is beneficial in patients with hyperandrogenism. Details: Preliminary clinical research in females with hyperandrogenism shows that taking dried extract of stinging nettle root 300-600 mg daily for approximately 4 months decreases total and free testosterone levels, but not menstrual cycle conditions, oily skin, or acne, when compared with taking spironolactone and cyproterone (91520).
Insect bite. Oral stinging nettle has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research shows that applying a homeopathic after-bite gel, containing stinging nettle, Echinacea, and marsh Labrador tea, on affected areas does not reduce erythema or itching after a mosquito bite when compared with placebo (89235).
Kidney stones (nephrolithiasis). Although there is interest in using oral stinging nettle for kidney stones, there is insufficient reliable information about the clinical effects of stinging nettle for this condition.
Myalgia. Although there is interest in using topical stinging nettle for myalgia, there is insufficient reliable information about the clinical effects of stinging nettle for this purpose.
Osteoarthritis. Small clinical studies suggest that topical stinging nettle may modestly improve pain in patients with osteoarthritis. It is unclear if oral stinging nettle is beneficial. Details: Topically, stinging nettle leaf may have a counterirritant effect which may improve osteoarthritis pain in some patients. A small clinical study in patients ages 45-82 with osteoarthritis of the thumb shows that applying raw stinging nettle leaf to the thumb for 30 seconds daily for 1 week reduces pain and disability when compared with white dead nettle leaf control (12490). However, in another small clinical study in patients with knee osteoarthritis, topical application of raw stinging nettle leaf to the knee for 1 minute daily for 7 days does not seem to be more effective for reducing pain than applying a leaf from a related stingless nettle (76412). Non-raw stinging nettle has also been tried. In a small open-label study, a formulation of stinging nettle extract (Liquid PhytoCaps Nettle Leaf, Gaia Herbs) 13.33% compounded with lipobase oil-in-water emulsion and applied to the affected area twice daily for 2 weeks, modestly improves pain and function in patients with radiologically confirmed osteoarthritis when compared with baseline (76414). The validity of this finding is limited by the lack of a comparator group. Stinging nettle has also been evaluated orally, in combination with other ingredients. A clinical study in adults with knee osteoarthritis shows that taking a specific combination solution (Rosaxan, medAgil Gesundheitsgesellschaft mbH) containing stinging nettle extract 160 mg, rose hip puree 20 grams, devil's claw 108 mg, and vitamin D 200 IU daily for 12 weeks improves symptoms by an additional 28% and pain scores by an additional 33% when compared with placebo (96741). It is unclear if this effect is due to stinging nettle, the other ingredients, or the combination.
Tinnitus. Oral stinging nettle has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in adults with tinnitus shows that taking a specific product containing stinging nettle, tansy, and rose hip (Neurotec, Rose Pharmed), 100 mg orally daily for 3 months does not improve auditory thresholds when compared with placebo. However, the product improved some subjective symptoms scores, such as perceived loudness and severity scores (110512).
Urinary tract infections (UTIs). Although there is interest in using oral stinging nettle for UTIs, there is insufficient reliable information about the clinical effects of stinging nettle for this condition. More evidence is needed to rate stinging nettle for these uses.

YOHIMBE

Antidepressant-induced sexual dysfunction. It is unclear if oral yohimbine, a constituent of yohimbe, is beneficial for patients with antidepressant-induced sexual dysfunction. Details: Small clinical trials suggest that taking yohimbine, a constituent of yohimbe, improves sexual dysfunction associated with selective serotonin reuptake inhibitors (SSRIs) (3305,3306,3307,3311,3313,3970,3971,3972,3973). It is unclear if yohimbe bark is beneficial.
Anxiety. There is limited evidence on the oral use of yohimbine, a constituent of yohimbe, for the management of various phobias. Details: A small clinical study in healthy adults with a fear of flying shows that taking yohimbine hydrochloride 10 mg as an adjunct to virtual reality exposure therapy (VRET) does not improve anxiety measures when compared with VRET alone (86819). However, another small clinical study in healthy adults with claustrophobia shows that taking yohimbine hydrochloride 10.8 mg prior to exposure-based treatment reduces peak fear after one week when compared with exposure-based treatment alone (86794). The effect of yohimbe bark has not been investigated in clinical research.
Athletic performance. It is unclear if oral yohimbine, a constituent of yohimbe, is beneficial for athletic performance. Details: A small clinical study in professional soccer players shows that taking yohimbine, a constituent of yohimbe, 20 mg daily for 3 weeks does not improve exercise performance or build muscle mass when compared with placebo (86785). However, a small crossover study in physically active females undergoing an anaerobic exercise test shows that taking a single dose of oral yohimbine 2.5 mg 20 minutes prior to repeated sprints increases average power output, total work, and heart rate and decreases average fatigue index when compared with placebo. Additionally, taking yohimbine decreases lactic acid levels and increases epinephrine levels when compared with baseline or placebo (107849). Due to the single-dose nature of this study, the effects of continued administration of yohimbine on athletic performance are unclear. The effects of yohimbe bark have not been investigated in clinical research.
Depression. It is unclear if oral yohimbine, a constituent of yohimbe, is beneficial in patients with depression. Details: A very small clinical study in patients with treatment-resistant major depressive disorder shows that taking yohimbine, a constituent of yohimbe, 30 mg daily for 10 days along with desipramine does not improve symptoms of depression when compared with desipramine alone (86834). Also, a small crossover trial in patients with major depressive disorder and/or a history of adverse childhood experiences shows that taking yohimbine 10 mg once does not alter approach-avoidance behaviors normally associated with depression when compared with placebo (111402). The effects of yohimbe bark have not been investigated in clinical research.
Dry mouth. It is unclear if oral yohimbine, a constituent of yohimbe, is beneficial for dry mouth. Details: A very small clinical study shows that taking yohimbine, a constituent of yohimbe bark, 18 mg daily for 5 days improves symptoms of dry mouth in individuals treated with antidepressants when compared with placebo (86886). The effect of yohimbe bark has not been investigated in clinical research.
Erectile dysfunction (ED). It is unclear if oral yohimbine, a constituent of yohimbe, is beneficial for ED. Details: The effects of yohimbe bark have not been investigated in clinical research. Most small clinical studies suggest that taking yohimbine, a constituent in yohimbe bark, seems to improve symptoms in adults with various types of ED, including organic, psychogenic, mixed, and others (3305,3307,3309,3311,3312,3313,10629,86827,86831,86878)(86882,86888,86896). A meta-analysis in patients with ED shows that taking 5-100 mg of oral yohimbine for 2-10 weeks increases the probability of erectile function improvement when compared with placebo. Also, the use of yohimbine in combination with either L-arginine or trazodone, but not as monotherapy, improves sexual function when compared with placebo (107848). These findings are limited by the high heterogeneity of the included studies. Due to insufficient data, guidelines from the American Urological Association do not recommend yohimbine as a treatment option for ED (86881).
Fatigue. Although there is interest in using oral yohimbe for fatigue, there is insufficient reliable information about the clinical effects of yohimbe for this purpose.
Obesity. Although there is interest in using oral yohimbe for obesity, there is insufficient reliable information about the clinical effects of yohimbe for this condition.
Orthostatic hypotension. It is unclear if oral yohimbine, a constituent of yohimbe, is beneficial in patients with orthostatic hypotension. Details: Some preliminary clinical research shows that taking a single dose of yohimbine 5.4 mg increases systolic blood pressure and standing diastolic blood pressure in patients with orthostatic hypotension when compared with placebo or pyridostigmine (86811,86890). However, other preliminary clinical research shows that taking yohimbine does not improve blood pressure in patients with orthostatic hypotension due to autonomic failure when compared with placebo (86821). The effect of yohimbe bark has not been investigated in clinical research. More evidence is needed to rate yohimbe for these uses.

ZINC

EFFECTIVE

Zinc deficiency. Orally or intravenously, zinc is effective for treating and preventing zinc deficiency. Details: Taking zinc orally or intravenously prevents and treats zinc deficiency (2619). However, routine zinc supplementation is not recommended (403). Zinc deficiency requiring supplementation may occur in patients with severe diarrhea, malabsorption syndromes, liver cirrhosis, and alcoholism; after major surgery, renal failure, and dialysis; or during long-term administration of total parenteral nutrition (3900,24321). Zinc supplementation (136 mg of elemental zinc per day) in patients with cirrhosis and zinc deficiency seems to improve liver function and glucose tolerance, possibly by increasing insulin-like growth factor (8624,87520).

LIKELY EFFECTIVE

Diarrhea. Oral zinc reduces duration and severity of acute diarrhea in malnourished children. Doses of 5-20 mg seem to be effective, while 5-10 mg daily is less likely to cause vomiting. Details: Most research, including meta-analyses and over 30 clinical trials, show that taking zinc orally reduces the duration and severity of acute and persistent diarrhea in malnourished or zinc-deficient children, but not in well-nourished children (87236,96074). Most studies have been conducted in Bangladesh and India, so it is unclear if these findings are generalizable to other geographic locations. The most comprehensive meta-analysis of clinical studies in children older than 6 months shows that zinc supplementation reduces the duration of acute diarrhea by about 11 hours and the duration of persistent diarrhea by about 16 hours when compared with placebo. However, zinc does not seem to reduce the duration of acute diarrhea in children younger than 6 months. Zinc supplementation seems to have the greatest benefit in children with clear malnutrition and diarrhea. In these children, zinc reduces diarrhea duration by about 26 hours and reduces the risk of diarrhea persisting through days 3, 5, and 7 by 18% to 24% when compared with placebo. There was no clear benefit of using zinc in a specific dose or salt form. The most common dose of zinc was 20 mg daily and salt forms included zinc sulfate, gluconate, and acetate (96074). Also, a large clinical trial in children with acute diarrhea shows that taking zinc 5 or 10 mg daily for 14 days is non-inferior to taking 20 mg. Furthermore, zinc 5 or 10 mg results in a respective 29% and 19% lower risk of vomiting within the first 30 minutes when compared with zinc 20 mg (104045). It's unclear whether zinc supplementation reduces mortality in children with diarrhea. A meta-analysis of clinical research in children under the age of five years shows that supplementation with zinc reduces the risk of mortality from diarrhea by 15% when compared with either placebo, other vitamin and/or mineral supplementation, or no supplementation (106239). However, many studies were conducted in hospitals where rates of mortality are low and were not adequately powered to determine whether zinc has an effect on mortality in children with acute diarrhea (87210,96074,106239).
Wilson disease. Taking zinc orally improves symptoms of this condition. Details: Zinc acetate (Galzin) is an FDA-approved orphan drug for treating this condition. Zinc blocks copper absorption and increases copper elimination in the stool of people with Wilson disease (2692,2693,87327). Small clinical studies suggest that taking zinc after 8 weeks of treatment with tetrathiomolybdate alone can improve Kayser-Fleischer rings, urine copper levels, and neurological symptoms for up to 6 years post-treatment (63588,87491).

Acne. Orally, zinc might help to reduce symptoms of acne. However, it's unclear how oral zinc compares to conventional acne treatments. Topical zinc doesn't seem to be beneficial if used alone. Details: Observational research has found that people with acne seem to have lower zinc levels in the serum and skin (104056). A meta-analysis of small, low quality clinical trials suggests that taking zinc sulfate or zinc gluconate 137-300 mg 2-3 times daily by mouth can modestly improve acne when compared with placebo (104056). However, not all individual trials show benefit (87002,104056). So far, it is not clear how oral zinc compares to other treatments. Trials comparing zinc sulfate with various tetracyclines have yielded conflicting results (6505,6506,86946,106233). One large open-label clinical trial shows that taking zinc sulfate 200 mg twice daily for 12 weeks is at least as effective as lymecycline 300 mg daily for reducing acne severity. Quality of life related to acne was modestly improved in the patients using zinc sulfate (106233). However, in another clinical trial, a 3-month treatment of oral zinc gluconate 30 mg daily reduced the number of acne lesions from baseline, but was not as effective as minocycline (86946). When applied topically, clinical research shows that zinc does not help treat acne when compared with placebo (87297,104056). However, when used in combination with erythromycin, topical zinc seems to result in improvement (819,820,2687,2688).
Acrodermatitis enteropathica. Oral zinc seems to improve symptoms of this rare genetic disorder. Details: Multiple case reports have found that taking oral zinc seems to help improve symptoms of acrodermatitis enteropathica, a rare disorder (821,2689,2690,2691). One case report in a female with necrolytic acral erythema and hepatitis C suggests that adding oral zinc sulfate 225 mg twice daily to interferon alfa-2b for 6 months contributed to resolving all lesions. Necrolytic acral erythema is categorized in the family of necrolytic erythemas that includes acrodermatitis enteropathica (6192).
Age-related macular degeneration (AMD). Oral zinc, especially in combination with antioxidant vitamins, seems to slow the progression of AMD. Details: Clinical research shows that taking elemental zinc 80 mg plus vitamin C 500 mg, vitamin E 400 IU, and beta-carotene 15 mg daily reduces the odds of progression to advanced AMD by 28%. In patients with more severe AMD, this combination reduced the odds of progression to advanced AMD by 34%. This combination also reduced the odds of visual acuity loss by 27% in patients with severe AMD (7303,11326). However, there is contradictory evidence about the effects of zinc plus antioxidants on visual acuity loss or the progression to advanced AMD in low-risk patients with AMD (6583,6584,7303). Some clinical evidence shows that, when taken without antioxidant vitamins, zinc supplementation does not slow the progression of existing AMD (6580,90069). However, a subgroup analysis of results from a large clinical trial that included patients with intermediate or advanced AMD suggests that the effect of zinc on AMD progression might vary depending on a patient's genetic predisposition. Complement factor H (CFH) and age-related maculopathy susceptibility 2 (ARMS2) are two genes for which specific variations (i.e., risk alleles) have been associated with an increased risk of AMD. Results from the retrospective subgroup analysis suggest that zinc supplementation may DECREASE the progression of AMD in patients with ARMS2 risk alleles and INCREASE the progression of AMD in patients with CFH risk alleles (90193). However, some experts question the results from this analysis due to the retrospective nature of the study (93045). Another retrospective analysis of similar data found that only zinc plus antioxidants, but not zinc alone, was beneficial for slowing the progression of AMD, regardless of the patient's genotype (93046). Consequently, the American Academy of Ophthalmology does not currently recommend routine genetic screening to determine which patients would benefit from zinc, antioxidants, or the combination. Instead, patients with intermediate or advanced AMD are recommended to take an antioxidant and zinc supplement similar to those used in the Age-Related Eye Disease Study (AREDS) and the Age-Related Eye Disease Study 2 (AREDS2) (93047). Large scale population studies suggest that increasing dietary intake of zinc might reduce the risk of developing AMD (6579,14257).
Child growth. Oral zinc seems to increase growth when taken by children and improve infant growth in the first year of life when taken by pregnant adults. Details: A meta-analysis of 8 clinical studies in healthy children over 2 years old shows that taking supplemental zinc 5-15 mg daily for 6-56 weeks modestly increases height and weight when compared with placebo. This analysis also shows that taking zinc may improve height for age, but not weight for age when compared with placebo (112474). Most of these studies were conducted in developing countries; results may not apply elsewhere. Another clinical study in pregnant adults in Peru shows that taking zinc 15 mg daily in addition to iron and folic acid, starting during the first or second trimester and continuing up to one month after delivery, modestly improves growth measures of infants at one year when compared with taking iron and folic acid alone. Improved growth measures include body weight, calf and chest circumference, and calf muscle area (87130).
Common cold. Oral zinc seems to help treat cold symptoms in adults. However, it is unclear if zinc is beneficial for common cold prevention. Details: Using zinc oral lozenges seems to be beneficial in helping TREAT the common cold in adults. The majority of clinical trials and analyses of clinical research show a significant decrease in the duration of symptoms of the common cold when adults take zinc gluconate or zinc acetate lozenges providing 9-24 mg of elemental zinc per dose. It is recommended that lozenges be taken every 2 hours while awake, starting within 48 hours of symptom onset for a total daily dose of at least 75 mg in order to attain a mean cold duration reduction of 3 days (333,334,335,337,6703,6705,87501,92212,106902). However, not all studies have been positive (333,338,339,6522,6700,87512). The reasons for these different findings are not clear, but might be due to differences in zinc formulations and doses and study methodologies. In some cases, flavoring agents such as citric acid, mannitol, and sorbitol might chelate zinc and decrease zinc ionization. Since ionization is thought to be necessary for zinc activity, a decrease in zinc ionization could decrease effectiveness (300,340,6522). Some of the positive studies have also been criticized for inadequately blinding the unpleasant, distinctive taste of zinc (6522,6706). Allergy and smoking status do not appear to impact the efficacy of zinc acetate lozenges (92212). Overall, zinc products may be beneficial for modestly reducing the duration of symptoms of the common cold in adults, but adverse effects such as bad taste and nausea may limit their usefulness (18216). There is conflicting evidence for the use of oral zinc products to PREVENT colds. Some clinical research suggests that taking zinc prophylactically does not prevent the common cold in adults (10780,10784) or children (341). However, other clinical research suggests that administering zinc gluconate lozenges can reduce the incidence of colds in children and adolescents (10803,86972). In a meta-analysis of 28 randomized controlled trials with a total of 5446 participants, oral zinc prevented 5 viral upper respiratory tract infections per 100 person months of zinc use when compared with placebo, with a number needed to treat (NNT) of 20 (106902). Intranasal zinc is not recommended for the prevention or treatment of the common cold due to the risk for anosmia. See the Adverse Effects section for more information. Some research shows that zinc nasal spray (as a sulfate, gluconate emulsion, or gluconium gel) reduces the severity and duration of cold symptoms; however, other research has found no effect (6471,8628,8629,10247,87035). Zinc nasal spray does not seem to prevent experimentally-induced colds (8628).
Coronavirus disease 2019 (COVID-19). While oral zinc does not seem to speed recovery from COVID-19 in non-hospitalized patients, an analysis of a small number of studies suggests that oral or intravenous zinc might reduce the risk of death in hospitalized patients with COVID-19. Details: A small observational study in patients with COVID-19 has found that lower serum zinc levels are associated with worse clinical outcomes, such as admission to the intensive care unit (ICU) and death, when compared with higher zinc levels (105681). Another small observational study has found that 96% of patients with confirmed COVID-19 were zinc-deficient based on plasma levels of zinc, and that these patients had lower plasma zinc levels than a group of individuals without COVID-19. However, plasma zinc concentrations were only weakly correlated with length of hospital stay and there was no correlation with morbidity or mortality (106236). One clinical study in adult outpatients with COVID-19 shows that taking zinc gluconate 50 mg daily at bedtime, alone or with vitamin C (ascorbic acid) 8000 mg daily, for 10 days does not reduce symptom severity when compared with standard care (104450). This study was terminated prior to complete enrollment due to a lack of effect with zinc and/or vitamin C supplementation. Limitations of this study include a lack of placebo control and blinding. Zinc supplementation also does not appear to enhance the clinical efficacy of hydroxychloroquine in patients with confirmed COVID-19 infection. Taking zinc sulfate 220 mg twice daily during a 6-day course of hydroxychloroquine does not improve the clinical recovery rate, reduce the mortality rate, or reduce the need for mechanical ventilation when compared with hydroxychloroquine alone (104818). Other research has evaluated zinc in hospitalized patients. Multiple meta-analyses of small and low-quality clinical studies, including randomized controlled trials and retrospective studies, involving hospitalized patients with COVID-19 shows that supplementation with oral or intravenous zinc is associated with a 29% to 43% reduction in the odds of in-hospital mortality when compared with control (109451,110631). However, in one meta-analysis, the odds of 30-day mortality were not different between groups (110631). These meta-analyses did not elevate the most effective form, dose, frequency, or duration of zinc supplementation (109451,110631). Additionally, a retrospective study in adults admitted to the ICU with COVID-19 has found that those who received oral zinc sulfate, 220 mg daily for a median of 11 days, had a lower 30-day mortality rate when compared with those who did not receive zinc. However, there was no difference in hospital length of stay or in-hospital mortality (106903).
Depression. Oral zinc seems to be beneficial when used in combination with antidepressant treatments. Details: Population research has found that higher zinc levels and higher dietary intake of zinc are associated with a 28% lower incidence of depression (90227,97139,104057). Oral zinc seems to be beneficial as an adjunct therapy in depression. A meta-analysis of small, low-quality studies in patients with major depression shows that taking zinc in addition to antidepressant therapy is associated with modestly improved depression symptoms when compared with antidepressant therapy alone (104044). Clinical studies used zinc doses of 7-25 mg daily for up to 12 weeks (86985,90221,104044). One small clinical study also shows that adding zinc to imipramine therapy might improve depression that was previously resistant to antidepressant treatment (87158). One clinical guideline also provisionally recommends use of zinc 25 mg elemental orally daily to treat patients with depression based on low-quality evidence. This guideline recommends use of chelated or picolinate zinc products over other forms of zinc (110318).
Diabetes. Oral zinc might modestly improve glycemic control in some patients. Details: A meta-analysis of 12 clinical studies in patients with diabetes shows that taking zinc supplements reduces fasting blood glucose by up to 20 mg/dL and glycated hemoglobin (HbA1c) by 0.35% when compared with control. However, when only high quality studies were included, the reduction in fasting blood glucose dropped to 12 mg/dL. Zinc seems to only have glycemic benefit in patients living in the Eastern hemisphere, and not the Western hemisphere. Also, glucose reduction seems to be higher with inorganic zinc formulations at doses of at least 30 mg daily taken for at least one month (104080). Zinc has also been evaluated for improving lipid parameters in patients with diabetes. A meta-analysis of nine studies in patients with diabetes shows that taking zinc reduces triglycerides by 17 mg/dL, but does not seem to affect low-density lipoprotein (LDL) or high-density lipoprotein (HDL) cholesterol levels, when compared with placebo (104041). The findings from these meta-analyses are limited by the high heterogeneity and small size of the included studies. Zinc has also been studied for gestational diabetes. Some clinical research in patients with gestational diabetes shows that taking zinc gluconate for 6 weeks, starting at 24-28 weeks' gestation, reduces fasting plasma glucose levels by about 10% and improves insulin resistance by 14% when compared to baseline (96072). However, taking zinc gluconate does not reduce the need for caesarean section or insulin therapy, or improve infant outcomes, such as size or health at birth, in these patients (96073).
Diaper rash. Topical and oral zinc seem to reduce the incidence and severity of diaper rash in infants. Details: Clinical research shows that administering oral zinc gluconate 10 mg daily for 4 months can reduce the incidence of diaper rash in infants when compared with placebo (87281). Other clinical research shows that applying 47% zinc oxide paste to affected areas for 5 days can improve the healing of diaper rash. However, the effect of zinc oxide paste is inferior to eosin 2% solution (86918).
Gingivitis. Topical zinc seems to reduce the development of gingivitis. Details: While some clinical research shows that zinc, in combination with triclosan, does not prevent plaque and gingivitis (24093,87020), most clinical research shows that using zinc toothpaste or mouthwash, alone or in combination with triclosan, can prevent plaque accumulation, gingivitis, or the formation of calculus (6523,6524,6525,6526,6527,6528,6529,87418,87507). However, most studies used zinc citrate in combination with triclosan, which is not available in the US (6523). For treating existing plaque, calculus, and gingivitis, some clinical research suggests that using zinc citrate 0.5% toothpaste three times daily for 3 months reduces calculus scores by 14% when compared with placebo (87205). However, other evidence suggests that stannous fluoride 0.454% toothpaste is more effective than zinc citrate 0.75% toothpaste for reducing plaque levels (87136).
Halitosis. Oral zinc seems to reduce halitosis when taken as a gum, mouth rinse, or candy. Details: Clinical research shows that chewing zinc-containing gum reduces volatile sulfur compounds and related odor levels when compared with placebo gum in patients with moderate to severe halitosis (87538). Clinical research also shows that using one of two mouth rinses (Halita, which contains 0.05% chlorhexidine and 0.14% zinc lactate, or Meridol, which contains 0.025% fluoride plus 0.2% zinc lactate) improves breath odor and volatile sulfur compounds by approximately two-fold when compared with mouth rinse containing only 0.05% fluoride or chlorhexidine 0.12% (90206). Additional clinical research shows that sucking a candy containing abrasive substances and zinc gluconate 0.5% or candy containing abrasive substances plus zinc 0.25% and propolis 1% improves breath malodor two- to three-fold when compared with sucking placebo candy (90196).
Herpes labialis (cold sores). Topical zinc seems to reduce the severity and duration of cold sores. Details: Applying zinc topically seems to help treat herpes simplex infection (6538,6539,8623,11051). Zinc sulfate seems to reduce the severity and duration of symptoms in both orolabial and genital herpes (6538,6539). Zinc oxide (0.3%) in combination with glycine cream applied topically every 2 hours to facial and circumoral herpes seems to reduce symptoms such as blistering, soreness, itching, and tingling. It can also reduce the duration of lesions from 6.5 days to 5 days when treatment is begun within 24 hours of onset of symptoms (8623). A specific combination product containing zinc oxide and L-lysine plus 14 other ingredients (Super Lysine Plus +) also seems to help decrease symptoms and duration of herpes lesions when applied topically every 2 hours (11051). However, zinc may not be effective for recurrent herpes simplex infections. In one clinical study, applying zinc sulfate 0.0025% or 0.05% solution to affected areas did not reduce the frequency, severity, or duration of herpes episodes when compared with a placebo solution in patients experiencing more than five episodes per year (87330).
Hypogeusia. Oral zinc might improve taste disturbance and taste acuity in people with hypogeusia of various etiologies. Details: A meta-analysis of low-quality studies in patients with taste disorders that are idiopathic or due to zinc deficiency shows that taking oral zinc modestly improves taste acuity when compared with placebo (104055). Studies tested zinc gluconate, zinc sulfate, zinc acetate, and zinc-carnosine as Polaprezinc (Promac, Zeria Pharmaceutical Co., Ltd.), containing 17-68 mg elemental zinc, daily for up to 12 weeks (104055). Zinc also might improve hypogeusia conditions unrelated to zinc deficiency, such as gustin/carbonic anhydrase VI deficiency, captopril-induced taste disturbances, hypogeusia due to chronic renal failure, and post-traumatic olfactory disorder (6543,6544,104055). It also seems be beneficial in radiation-induced dysgeusia. A meta-analysis of three small clinical trials shows that oral zinc reduces the risk of radiation-induced dysgeusia by 28%, but does not improve taste acuity when compared with placebo (104043). However, patients with hypogeusia from other causes may not benefit. Zinc supplementation does not seem to improve taste perception when compared with placebo in patients with acetazolamide-induced taste dysfunction or chemotherapy-induced taste dysfunction (87388,90214).
Leishmania lesions. Oral zinc and intralesional injections of zinc might improve healing of these lesions. Details: Clinical research shows that taking zinc sulfate 2.5-10 mg/kg orally in three divided doses daily, improves the cure rate of cutaneous leishmania lesions after 45 days when compared with no treatment (86935). Other clinical research shows that intralesional injections of zinc sulfate 2% solution for 6 weeks improves cure rates of cutaneous leishmania lesions when compared with no treatment (6587). However, intralesional injections with zinc sulfate solution does not appear to be more effective than intralesional injections of meglumine antimoniate (Glucantime), hypertonic saline, or sodium stibogluconate (6587,86996,87008).
Leprosy. Oral zinc seems to be beneficial when used in combination with anti-leprosy drugs. Details: Zinc levels appear to be reduced in people with leprosy. Early clinical research suggests that the addition of zinc improves tolerance of the anti-leprosy drug regimen and might allow for lowering or eliminating steroid doses in erythema nodosum leprosum, a severe form of leprosy (6534,6535,6536,6537).
Low birth weight. Oral zinc supplementation seems to improve growth in low birth weight infants. Whether oral zinc can improve other outcomes, including mortality, is unclear. Taking oral zinc during pregnancy does not seem to reduce the risk of having a low birth weight infant. Details: While there is some mixed evidence regarding the effects of zinc supplementation on weight gain and length in infants born with low birth weight (87172,87452,90229), a meta-analysis of 14 clinical trials in preterm or low birth weight infants receiving breastmilk shows that zinc supplementation, typically 5-7 mg daily started at birth and continued for up to 12 months with or without other micronutrients, increases weight by around 380 grams, length by around 3 cm, and head circumference by around 0.6 cm when compared with control (109455). There is also mixed evidence regarding the effect of zinc supplementation on other outcomes in low birth weight infants. A large clinical trial in full-term, underweight infants aged 1-6 months in developing countries shows that adding zinc to nutritional supplementation reduces the risk of mortality by about 68% when compared with nutritional supplementation not containing zinc (8920). A small clinical trial in very low birth weight preterm infants born in an industrialized country shows that adding zinc to multivitamin supplementation appears to reduce the occurrence of necrotizing enterocolitis and mortality. However, adding zinc does not appear to prevent late-onset sepsis, bronchopulmonary dysplasia, or retinopathy of prematurity (90229). A meta-analysis of these trials and two other studies in low birth weight infants shows that supplementation with zinc reduces the risk of all-cause mortality by 52% when compared with either placebo, other vitamin and/or mineral supplementation, or no supplementation (106239). Another small clinical study in low birth weight and preterm infants born in a developing country shows that zinc supplementation seems to improve alertness and attention when compared with placebo (97140). However, a meta-analysis of 14 clinical trials in preterm or low birth weight infants receiving breastmilk shows that zinc supplementation, typically 5-7 mg daily started at birth and continued for up to 12 months with or without other micronutrients, does not improve mental or psychomotor development or reduce the risk of mortality, hospitalization, acute respiratory infection, or sepsis when compared with control (109455). Some of these discrepant findings may be due to differences in patient populations (hospitalized, non-hospitalized), milk sources (breastfed, formula-fed, or both), and duration of follow-up. The effect of zinc intake or supplementation during pregnancy has also been evaluated. Population research has found that low dietary intake of zinc during pregnancy is associated with low birth weight in infants; similarly, zinc supplementation is associated with increased infant weight at birth (87471,105678). However, a meta-analysis and a large clinical study show that zinc supplementation during pregnancy does not reduce the risk of having a low birth weight infant (97142,105679). Reasons for the discrepancies may be due to differing zinc status prior to supplementation. Also, numerous factors contribute to the risk of low birth weight, which may confound research on the use of zinc supplementation alone.
Peptic ulcers. Oral zinc seems to treat and prevent peptic ulcers. Details: Taking zinc orally seems to help treat and prevent peptic ulcers (6588,6589,6591). Some clinical research shows that zinc acexamate improves peptic ulcers when compared with placebo (6589,87285), and seems to be as effective as H2-receptor antagonist drugs (6589,87533). It is not known if other zinc salts are effective.
Pneumonia. Oral zinc might reduce the risk for pneumonia in children, but it doesn't seem to improve symptoms in children that already have pneumonia. Details: A meta-analysis of four clinical studies shows that giving zinc supplements to children, ages 3 months to 5 years living in developing countries, some of whom were undernourished, reduces the risk of pneumonia incidence by 21% when compared with placebo (104047). Another meta-analysis of clinical research in children under the age of five years shows that supplementation with zinc reduces the risk of pneumonia mortality by 21% when compared with either placebo, other vitamin and/or mineral supplementation, or no supplementation (106239). The research on TREATING existing pneumonia in children is inconsistent. Most meta-analyses and clinical studies in children ages 2 months to 5 years with severe pneumonia show that taking elemental zinc in addition to antibiotic therapy does not improve symptom resolution or the time to recovery when compared with antibiotic therapy alone. Zinc also does not seem to reduce mortality in these patients (87248,90197,96080,98131,104042). However, two clinical studies in children in the same age group with pneumonia suggest that adding zinc to standard antibiotic therapy improves symptom resolution and decreases hospital stay when compared with placebo (11052,87242). Reasons for these discrepancies are not clear, but may be related to zinc status prior to treatment.
Prematurity. Analyses of clinical studies suggest that oral zinc improves growth in premature infants. Whether zinc improves development or reduces the risk of mortality in these patients is unclear. Details: A meta-analysis of small clinical trials in hospitalized infants born prematurely suggests that receiving enteral zinc supplementation at a dose of up to 10 mg daily reduces mortality and might improve short-term weight gain when compared with placebo (105687). Another meta-analysis of small clinical studies in preterm infants shows that adding zinc to formula or to a multivitamin seems to modestly increase infant weight and height and improve motor development when compared with control (105676). A larger meta-analysis of 14 clinical trials in preterm or low birth weight infants receiving breastmilk shows that zinc supplementation, typically 5-7 mg daily started at birth and continued for up to 12 months with or without other micronutrients, increases weight by around 380 grams, length by around 3 cm, and head circumference by around 0.6 cm when compared with control. However, zinc supplementation did not improve mental or psychomotor development or reduce the risk of mortality, hospitalization, acute respiratory infection, or sepsis when compared with control (109455). These analyses are limited by imprecision as well as a high risk of bias in some of the included studies. Some of the discrepant findings may be due to differences in patient populations (hospitalized, non-hospitalized), milk sources (breastfed, formula-fed, or both), and duration of follow-up.
Pressure ulcers. Topical zinc paste seems to work as a skin barrier and improve pressure ulcer healing. Oral zinc has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study shows that applying zinc oxide paste to pressure ulcers daily for 8 weeks reduces necrotic tissue and decreases the surface area of skin pressure ulcers similarly to using a topical streptokinase-streptodornase product (Varidase) (87331). Other small clinical studies show that applying zinc oxide paste to pressure ulcers daily for 8-12 weeks improves healing similarly to a hydrocolloid dressing (Duoderm) (87181) or a specific barrier film product (Cavilon No Sting Barrier Film) (87017). Oral zinc has been evaluated in combination with other ingredients for the treatment of grade II-IV pressure ulcers. Two small clinical studies in hospitalized patients shows that administering an oral nutritional supplement enriched with zinc, L-arginine, and vitamin C improves ulcer healing when compared with a standard diet (31953,87173). Also, clinical research in patients living in long-term care facilities shows that taking an oral nutritional supplement enriched in protein, zinc, L-arginine, and vitamin C daily for 9 weeks reduces ulcer area and decreases oozing when compared to baseline (32045). The validity of this finding is limited by the lack of a comparator group.
Sickle cell disease. Oral zinc seems to improve symptoms of sickle cell disease in patients with zinc deficiency. Details: Taking zinc orally seems to help reduce symptoms of sickle cell disease in people with zinc deficiency (6594,6595,6596,8626,87343). Taking zinc supplements also seems to decrease the occurrence rate of sickle-cell crises and infections (6594,6596,90228). Additionally, zinc might reduce the number of hospitalizations for sickle cell crises, although the severity of the crises that do develop is not necessarily decreased by taking zinc supplements (6594,6596). In prepubertal children and adolescents with homozygous sickle cell disease, taking zinc seems to improve growth, height, and weight gain (8626,87403).
Warts. Oral and topical zinc seem to improve the cure rate of cutaneous warts. Details: A small clinical study suggests that applying zinc sulfate 10% solution three times daily for 4 weeks improves plane warts, but not common warts, when compared with distilled water (87094). Another small clinical study suggests that applying topical zinc oxide 20% ointment twice daily for up to 3 months seems to have a similar cure rate as ointment containing salicylic acid 15% with lactic acid 15% (87082). Taking zinc orally may also be effective in treating warts (87227). A meta-analysis of low quality clinical studies shows that taking zinc sulfate orally improves the odds of curing cutaneous warts nearly 17-fold when compared with respective controls (87227). Preliminary clinical research in adults treated with cryotherapy for anogenital warts shows that taking zinc gluconate 30 mg orally three times daily for 2 months does not reduce the number of warts when compared with placebo (111445).

Alopecia areata. Oral zinc does not seem to improve symptoms of this condition. Details: Although there is preliminary evidence that suggests zinc in combination with biotin might be helpful for alopecia areata (6932), most studies indicate that zinc is not effective for alopecia areata, alopecia totalis, or alopecia universalis (6931,6932).
Cystic fibrosis. Oral zinc does not improve cystic fibrosis symptoms or progression. Details: Clinical research shows that taking supplements providing 30-90 mg of elemental zinc for 6 weeks to one year does not improve lung function when compared with placebo in children and adolescents with cystic fibrosis (87066,87113,96079). One clinical study also shows that taking elemental zinc for one year does not reduce the number of days requiring oral or intravenous antibiotics for pulmonary infections (96079). However, one study shows that taking zinc can reduce the number of days of oral antibiotic use when compared with placebo (87113).
HIV/AIDS. Oral zinc does not seem to improve outcomes in patients with HIV. Details: Clinical research in adult HIV patients with normal or low zinc levels shows that taking elemental zinc 12-15 mg daily orally for 18 months along with antiretroviral therapy does not improve viral load, CD4/8 counts, or mortality when compared with placebo (87036,87216,105686). In children with HIV-1, clinical research shows that administering zinc sulfate, providing 10 mg elemental zinc, daily for 6 months does not improve mortality, viral load, or CD4 counts when compared with placebo (82377).
HIV/AIDS-related pregnancy complications. Oral zinc does not prevent pregnancy complications related to HIV infection. Details: Adding zinc 25 mg orally during pregnancy does not seem to reduce parent-to-child vertical transmission of HIV, infant mortality, birth weight, or gestational period in HIV-infected females with low zinc levels (11054,87034). Also, one clinical study in HIV-1-infected pregnant patients suggests that supplemental zinc can increase the risk of wasting, as assessed by weight and mid-upper arm circumference, by 170% when compared with placebo (87034).
HIV/AIDS-related wasting. Oral zinc does not seem to improve HIV-related wasting syndrome. Details: A clinical study in patients with HIV-related wasting syndrome shows that taking zinc orally in combination with vitamins and albendazole does not seem to improve diarrhea or mortality when compared with taking albendazole alone (6564).
Infant development. Oral zinc does not seem to improve infant mental and psychomotor development. Details: Clinical research, including a meta-analysis of eight studies, shows that giving zinc to infants or children at high risk for zinc deficiency does not improve mental and psychomotor development when compared with placebo (87013,90209). In another meta-analysis of studies in children whose baseline zinc status was not specified, there was no beneficial effect of zinc supplementation on mental or psychomotor development at 6 or 12 months of age (104817).
Inflammatory bowel disease (IBD). Oral zinc does not improve symptoms of IBD. Details: Some clinical research shows that taking zinc orally does not seem to help treat IBD (6913,6915,6916).
Influenza. Oral zinc does not seem to reduce the risk for influenza. Details: Supplemental zinc seems to improve cell-mediated immune response in elderly people (824), but it does not seem to have a significant effect on antibody response and incidence of influenza infection after the vaccine (6553,6563). Additionally, zinc supplementation in patients on hemodialysis, who have a high risk of zinc deficiency, does not seem to improve response to influenza vaccine (10809). Taking zinc supplements orally is unlikely to improve immune function in people without risk factors for zinc deficiency (10789). However, there is preliminary evidence that suggests zinc along with selenium might reduce the incidence of infections in institutionalized older patients (8921).
Otitis media. Oral zinc does not prevent otitis media in children. Details: A meta-analysis of clinical research shows that taking elemental zinc 3-70 mg daily for up to 24 months does not prevent the occurrence of ear infections in children from low- or middle-income countries (87258).
Pre-eclampsia. Oral zinc taken prenatally does not seem to be beneficial for pre-eclampsia prevention. Details: A meta-analysis and a large clinical study show that zinc supplementation during pregnancy does not reduce the risk of pre-eclampsia when compared with placebo (97142,105679).
Prostate cancer. Oral zinc does not reduce the risk for prostate cancer or prostate cancer-related mortality. Details: Some epidemiological research has found an inverse relationship between dietary zinc intake and prostate cancer (96075). Also some clinical research shows that taking zinc 20 mg in combination with vitamin C 120 mg, vitamin E (alpha-tocopherol) 30 mg, beta-carotene 6 mg, and selenium 100 mcg daily for an average of 8 years might reduce the risk of prostate cancer in men with normal PSA levels; however, it does not seem to be beneficial for reducing the risk of prostate cancer in patients with PSA levels above 3 mcg/L (14135). However, some evidence raises concern that zinc might actually INCREASE the risk of prostate cancer. A large-scale population study found that taking more than 100 mg of supplemental zinc daily or taking supplemental zinc for 10 or more years doubles the risk of developing prostate cancer (10306). Another large-scale population study shows that men who take a multivitamin more than seven times per week and who also take a separate zinc supplement have a significantly increased risk of prostate cancer-related mortality (15607). Despite these studies suggesting the potential for adverse effects of zinc, a meta-analysis of mainly population research has found that there is no association between zinc intake and the risk of prostate cancer (96075).
Psoriasis. Oral zinc does not reduce the severity of psoriasis symptoms. Details: Zinc epidermal levels are reportedly lower in people with psoriasis (6509). However, taking zinc orally does not seem to help treat psoriasis (6513,6514,6912,87363). Zinc supplementation has no effect on the psoriasis area and severity index (6513,6514).
Rheumatoid arthritis (RA). Oral zinc does not treat symptoms of RA. Details: Multiple clinical studies in patients with RA show that taking zinc orally does not improve function or symptoms when compared with baseline or control (6517,6518,6519,87406).
Sexual dysfunction. Oral zinc does not improve sexual function in males with chronic kidney disease (CKD). Details: Clinical research shows that zinc supplementation does not improve sexual activity or libido when compared with placebo in males with sexual dysfunction secondary to CKD (6708,6568,87220,87386,87416). In fact, one clinical study shows that taking zinc can decrease the frequency of intercourse by 76% when compared with placebo in patients with CKD-related sexual dysfunction (87220).
Tinnitus. Oral zinc does not improve severity of tinnitus or reduce tinnitus-related disability. Details: A meta-analysis of three small clinical trials in adults with tinnitus shows that taking elemental zinc 50 mg daily for up to 16 weeks does not improve tinnitus severity, or disability from tinnitus when compared with placebo (104051).

LIKELY INEFFECTIVE

Malaria. Oral zinc does not prevent or treat malaria in undernourished children or pregnant adults in developing countries. Details: A meta-analysis of clinical research in children or pregnant adults shows that taking zinc orally, alone or in combination with other supplements, for does not reduce the risk of malaria parasitemia (111444). A large multi-country study in zinc-deficient preschool children with acute malaria shows that taking zinc supplements does not affect fever, parasitemia, or hemoglobin when compared with placebo (10246). An even larger clinical study of over 40,000 children with malaria aged 1-36 months shows that taking zinc 5-10 mg daily orally for approximately 17 months does not reduce mortality when compared with placebo (87078). Zinc supplements also do not appear to protect against infection by Plasmodium falciparum (8638,87235,86937). However, one small study in children with low and high levels of parasitemia shows that taking zinc 10 mg daily for 46 weeks may lower the incidence of fever episodes by 38% and 69%, respectively, when compared with placebo (86937).

Age-related cognitive decline. It is unclear if oral zinc is beneficial in patients with age-related cognitive decline. Details: An epidemiological study based on elderly adults enrolled in the National Health and Nutrition Examination Survey (NHANES) has found that taking zinc may improve cognition in a non-linear manner. Daily doses below 9 mg and 8 mg in males and females, respectively, showed a positive association with cognitive function, but doses above that level showed no association. Additionally, high intake of both zinc and selenium was associated with improved cognition in females, but not in males (108446). Dietary intake was collected from two patient-reported 24-hour recalls and cognition was only measured once, limiting the validity of these findings.
Alcohol-related liver disease. It is unclear if oral zinc is beneficial in patients with alcoholic-related liver cirrhosis. Details: A small clinical study in patients with alcoholic liver cirrhosis shows that taking zinc sulfate 600 mg daily for 6 weeks improves liver function, based on increased alkaline phosphatase activity and reduced serum bilirubin, when compared to baseline (87325).
Anorexia nervosa. Oral zinc seems to improve weight gain in people with anorexia nervosa. Details: Anorexia nervosa might be linked with zinc deficiency. Small clinical trials in adolescents and adults with anorexia nervosa show that oral zinc supplements might help increase weight gain and improve depressive symptoms when compared with placebo (6905,6906).
Arsenic poisoning. Oral zinc has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study shows that taking zinc 4 mg in combination with spirulina extract 500 mg daily for 16 weeks can decrease skin manifestations and reduce arsenic levels in the urine and in hair of patients with chronic arsenic poisoning (18301).
Asthenopia (eye strain). Oral zinc has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A very small clinical study in adults without dry eye disease shows that taking a specific combination product containing zinc 10 mg, L-carnitine 50 mg, elderberry fruit extract 300 mg, currant 100 mg, and Eleutherococcus root 50 mg (Meramirt CM) orally once daily for 1 month improves measures of eye strain and contrast sensitivity when compared to baseline. Improvements in these measures were lacking in the control group (111295). Statistical comparison between the two groups was not reported. It is unclear if these effects are due to zinc, other ingredients, or the combination.
Athletic performance. Oral zinc has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A very small clinical study in sleep-deprived recreational athletes shows that taking a combination of zinc 90 mg, magnesium 1350 mg, and vitamin B6 31.5 mg orally for 3 nights at bedtime does not improve grip strength, squat, or bench press performance when compared with placebo (113655).
Atopic dermatitis (eczema). It is unclear if oral zinc is beneficial for alleviating eczema in children. Details: A small clinical study in children with eczema shows that taking zinc sulfate 185.4 mg orally daily for 8 weeks does not appear to improve the surface area affected and degree of erythema, symptom scores of itch and sleep disturbance, or topical steroid use when compared with placebo. Also, plasma zinc levels appear to be normal in children with eczema (6911).
Attention deficit-hyperactivity disorder (ADHD). Oral zinc might improve certain symptoms in children with ADHD. Details: Observational research has found that lower serum zinc levels are both more prevalent in children with ADHD and are linked to worsened response to stimulant therapy (9965,9966,9967). Based on this evidence, there is some interest in using zinc to improve symptoms in children with ADHD. A meta-analysis of six small clinical trials shows that although taking zinc modestly improves overall symptoms of ADHD when compared with placebo, there is no effect on hyperactivity or inattention when these outcomes are examined separately. The sub-analyses conducted for these two separate outcomes included only 3 studies. Most, but not all, of the included studies were conducted in children also receiving methylphenidate treatment (106240). Elemental zinc, usually as sulfate, was typically used in doses of 10-40 mg daily for 6-12 weeks (11350,12060,106240). There is some evidence that zinc could be most helpful in children with a high body mass index (BMI), low zinc levels, and low free fatty acid levels (11350). It is unclear if zinc is beneficial in children who are not already taking stimulant medications. One clinical guideline also provisionally recommends against use of oral zinc to treat patient with ADHD based on low-quality evidence (110318).
Autism spectrum disorder. It is unclear if oral zinc is beneficial in children with autism spectrum disorder. Details: One small clinical study conducted in children with autism spectrum disorder shows that taking zinc 15-30 mg orally, alone or as add-on therapy to amphetamine, does not improve attention deficit hyperactivity disorder (ADHD) symptoms when compared with placebo (98711). However, the optimal mg/kg dose of amphetamine was shown to be 37% lower for those children also taking zinc 15 mg twice daily when compared with those taking placebo (98711).
Autoimmune thyroiditis. It is unclear if oral zinc is beneficial in children with autoimmune thyroiditis. Details: A small clinical study in children aged 3-18 years with autoimmune thyroiditis shows that taking zinc acetate 25 mg daily in addition to standard therapy for 12 weeks does not change thyroid auto-antibody levels, thyroid function tests, or oxidative stress markers when compared with standard therapy alone. However, subjects taking zinc did not require escalation in levothyroxine doses when compared with the control group control group, which did require levothyroxine dose escalation (113661).
Behcet disease. It is unclear if oral zinc is beneficial in patients with Behcet disease. Details: A small clinical trial in patients with Behcet disease shows that taking zinc gluconate 30 mg daily for 12 weeks does not improve disease activity scores, quality of life, or measures of inflammation when compared with placebo (109453).
Benign prostatic hyperplasia (BPH). Although there is interest in using oral zinc for BPH, there is insufficient reliable information about the clinical effects of zinc for this condition.
Beta-thalassemia. It is unclear if oral zinc is beneficial in patients with beta-thalassemia major. Details: A small clinical study in children recently diagnosed with beta-thalassemia major shows that initiating zinc sulfate in addition to standard blood transfusions increases linear growth rate when compared with transfusions alone (87329). Another small clinical study in adult and pediatric patients with thalassemia major and low bone mass shows that taking zinc 25 mg daily (as zinc sulfate) for 18 months improves whole-body bone mineral content, as well as hip and spine bone mineral density, by small amounts when compared with placebo (90208).
Brain tumor. It is unclear if dietary zinc is beneficial for reducing the risk for brain cancer. Details: Population research has found that zinc intake is not associated with a reduced risk of developing brain cancer (87098).
Breast cancer. It is unclear if increased dietary zinc intake is beneficial for reducing the risk for breast cancer. Details: Population research has found that neither zinc intake nor blood levels of zinc are associated with a reduced risk of breast cancer (106229).
Bronchiolitis. It is unclear if oral zinc is beneficial for viral bronchiolitis in infants and children. Details: A small clinical study in children 2 years or younger with acute viral bronchiolitis shows that taking elemental zinc 10-20 mg as zinc sulfate for 5 days improves clinical recovery and reduces the duration of hospital stay by almost one day when compared with placebo. After 72 hours, 98% of infants and children taking zinc were considered fully recovered, compared to only 52% of infants taking placebo (96076).
Burning mouth syndrome. Topical zinc has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in patients with burning mouth syndrome shows that taking zinc 15 mg and vitamin C 35 mg once daily, along with a vitamin B complex twice daily, for 30 days modestly decreases pain and burning when compared to baseline (105195). The validity of this finding is limited by the lack of a comparator group. Furthermore, it is unclear if the benefit is due to zinc, other vitamins, or the combination.
Burns. Intravenous zinc has only been evaluated in combination with other ingredients; its effect when used alone is unclear. The effects of oral zinc for burn healing are unclear. Details: Administering zinc intravenously in combination with other minerals seems to improve the outcomes of burn patients. Supplementation with zinc, copper, and selenium appears to improve wound healing, reduce pulmonary infections, and shorten intensive care unit stay in patients with serious burns (6520,87085). The effect of supplementation with zinc alone is unclear.
Canker sores. It is unclear if oral zinc is beneficial in patients with canker sores. Details: Evidence for the use of zinc in canker sores is conflicting. A small clinical crossover study in patients with recurrent canker sores shows that taking zinc sulfate 660 mg daily for 3 months does not improve the size or frequency of canker sore ulcers when compared with control (6592). However, another clinical study in patients with recurrent sores and low or normal zinc levels shows that taking zinc sulfate 220 mg daily for 1 month reduces recurrence of sores when compared with placebo (86964). Reasons for conflicting results are unclear. Zinc might be beneficial when used in a muco-adhesive formulation. A small clinical study in patients with canker sores shows that taking a muco-adhesive zinc sulfate 5 mg tablet three times daily for 7 days reduces pain and speeds up healing when compared with placebo (104048).
Cataracts. Oral zinc has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Taking zinc orally in combination with antioxidant vitamins does not seem to help treat or prevent cataracts. Taking elemental zinc 80 mg plus vitamin C 500 mg, vitamin E 400 IU, and beta-carotene 15 mg daily does not seem to have any effect on the development or progression of age-related lens opacities (cataracts) or the need for cataract surgery in well-nourished people 55-80 years of age. However, it is unknown whether earlier intervention and/or a longer period of treatment with supplements would have any effect on cataracts (7304).
Chemotherapy-induced acral erythema. It is unclear if oral zinc reduces the severity of acral erythema induced in patients treated with the vascular endothelial growth factor receptor-tyrosine kinase inhibitors (VEGFR-TKIs) treatment regorafenib. Details: A small study in patients with metastatic colorectal cancer undergoing treatment with regorafenib shows that taking zinc gluconate 78 mg twice daily reduces the proportion of patients with more severe acral erythema when compared with control. Though there is no association in the zinc treatment group, lower serum zinc levels seem to correlate with more severe acral erythema in the control group, suggesting a possible role of zinc deficiency in the pathogenesis of acral erythema (112472). The validity of this study is limited by the lack of blinding.
Chemotherapy-related fatigue. It is unclear if oral zinc improves symptoms in patients with fatigue due to chemotherapy. Details: A small clinical study in patients undergoing 4 or more cycles of chemotherapy for colorectal cancer shows that taking zinc 70 mg daily for 16 weeks does not improve fatigue or quality of life when compared with placebo (97141).
Chronic fatigue syndrome (CFS). Oral zinc has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Clinical research in females with CFS shows that taking zinc 10 mg as zinc sulfate plus melatonin 1 mg daily for 16 weeks modestly reduces self-reported symptoms of physical fatigue when compared with placebo. However, there was no effect on cognitive or psychological symptoms, sleep, or symptoms of anxiety or depression (106241). This study may not have been adequately powered to detect differences between groups.
Cirrhosis. It is unclear if zinc is beneficial for reducing cirrhosis-related mortality. Details: A meta-analysis of four small clinical trials shows that zinc supplementation does not seem to reduce mortality in patients with cirrhosis when compared with control (104054). This finding is limited due to the heterogeneity and small size of the available studies.
Cognitive function. It is unclear if zinc is beneficial for cognitive function. Details: A very small clinical study in adults with overweight and obesity shows that taking supplemental zinc 30 mg daily for 12 weeks improves some measures of cognitive function and executive processing but does not improve verbal fluency when compared with placebo (112471). Zinc has also been evaluated in combination with other ingredients. A small clinical trial in healthy adults shows that taking a specific product containing a combination of zinc 9 mg, Lactobacillus helveticus, Lactiplantibacillus plantarum, Bifidobacterium longum, and other ingredients (Puraflor, GSK Consumer Healthcare, Milano, Italy) orally daily for 4 weeks does not affect cognitive performance during acute stress when compared with placebo (110923).
Colorectal adenoma. Oral zinc has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A large clinical study shows that taking a combination supplement containing zinc 30 mg, selenium 200 mcg (as l-selenomethionine), vitamin A 2 mg (as retinol), vitamin C 180 mg, and vitamin E 30 mg (as D-a-tocopherol acetate) by mouth daily for 5 years or until the recurrence of an adenoma reduces the risk of recurrent large-bowel adenomas by approximately 40% when compared with placebo (92903). It is not clear if the benefit is due to zinc, other supplements, or the combination.
Colorectal cancer. It is unclear if oral zinc is beneficial for reducing colorectal cancer risk. Details: Population research has found that increased intake of zinc is associated with a 17% to 20% reduced risk of colorectal cancer (90213,90220).
Congenital heart disease. It is unclear if oral zinc is beneficial for reducing the risk of congenital heart defects. Details: An observational study in pregnant adults has found that consuming the recommended nutritional intake of zinc may be associated with a lower risk of total congenital heart defects in infants, including atrial and ventricular septal defects, when compared with low zinc intake. This association appears to persist despite copper or selenium intake (108445).
Critical illness (trauma). It is unclear if oral zinc is beneficial for critically ill patients. Details: A meta-analysis of two small randomized clinical trials in adults with head trauma shows that supplementing zinc, given as 120 mg elemental zinc orally daily or 12 mg elemental zinc intravenously daily for 15 days to 3 months, regardless of serum zinc levels, does not improve the risk of 30-day mortality when compared with control (111290). However, the study may have been inadequately powered to detect a difference between groups.
Dementia. Although there is interest in using oral zinc for dementia, there is insufficient reliable information about the clinical effects of zinc for this condition.
Diabetic foot ulcers. Although there is interest in using oral zinc for diabetic foot ulcers, there is insufficient reliable information about the clinical effects of zinc for this condition.
Diabetic neuropathy. It is unclear if oral zinc is beneficial in patients with diabetic neuropathy. Details: A small clinical study in patients with poorly-controlled diabetic neuropathy shows that taking zinc sulfate 660 mg daily for 6 weeks improves motor nerve conduction velocity and reduces fasting and postprandial blood sugar when compared to baseline (86933). The validity of this finding is limited by the lack of statistical comparison to the control group.
Down syndrome. It is unclear if oral zinc is beneficial for improving immune function in people with this condition. Details: A very small clinical study in Down syndrome patients with zinc deficiency shows that taking zinc sulfate 1 mg/kg daily for 2 months seems to improve immune function and reduce recurrent infections when compared with baseline (87289). The validity of this finding is limited by the lack of a control group. Another small clinical study in children with Down syndrome shows that zinc 25-50 mg daily for 6 months does not improve immune function when compared with placebo (87278). Reasons for the discrepancies may be related to the dose of zinc or zinc status at baseline.
Dysmenorrhea. It is unclear if oral zinc is beneficial in patients with dysmenorrhea. Details: Preliminary clinical research in females aged 13 to 21 years with primary dysmenorrhea shows that taking zinc sulfate 40 mg orally daily for the first 3 days of menstruation for three cycles reduces mean pain scores by 51% when compared with placebo (111446).
Epilepsy. There is limited evidence on the oral use of zinc in children with intractable seizures. Details: A small clinical study in children with intractable epilepsy shows that taking elemental zinc 1 mg/kg daily as zinc sulfate heptahydrate for 6 months reduces seizures when compared with placebo. About 31% of children taking zinc experienced a 50% decrease in seizure frequency, compared to only 5% of children taking placebo (96078).
Erectile dysfunction (ED). It is unclear if oral zinc is beneficial in patients with erectile dysfunction. Details: A moderate-sized, open-label clinical study in adults with mild-to-moderate ED shows that taking a specific combination supplement (Icarifil, Anvest Health S.p.A) containing zinc 15 mg, L-carnitine, L-citrulline, tribulus, and other ingredients daily for 3 months improves patient-reported erectile function when compared to baseline. Additionally, taking the supplement with tadalafil improves some, but not all, patient-reported assessments of erectile function when compared with taking tadalafil alone (114989). It is unclear if this effect is due to zinc, other ingredients, or the combination. Additionally, the interpretation of these results is limited by poor methodology, including the use of per-protocol analysis and lack of a placebo group.
Esophageal cancer. It is unclear if oral zinc is beneficial for esophageal cancer prevention. Details: Population research in Chinese and Iranian patients has found that low intake of zinc is associated with an increased risk of esophageal squamous cell cancer (17205,87059). However, other population research in patients from America, Europe, or Asia has found that dietary zinc intake is not associated with esophageal cancer risk (90213).
Fatigue. It is unclear if oral zinc is beneficial for reducing fatigue in older individuals. Details: A clinical study in adults 50 years and older, some with below-normal levels of zinc at baseline, shows that taking zinc 30 mg daily for 70 days improves subjective fatigue when compared with no intervention (105675). The validity of this finding is limited due to a lack of placebo control and potential performance bias. Additionally, it is unclear whether baseline zinc status alters the benefits of zinc supplementation.
Fecal incontinence. Topical zinc has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in females with fecal incontinence shows that topically applying an ointment containing zinc sulfate 1% and aluminum sulfate 5% to the anal canal mucosa three times daily for 4 weeks improves symptoms approximately twice as much as a placebo ointment. Quality of life related to the incontinence also improved (90219).
Gastric cancer. It is unclear if dietary zinc is beneficial for gastric cancer prevention. Details: Population research has found that increased dietary zinc intake is not associated with a decreased risk of gastric cancer (90213).
Head and neck cancer. It is unclear if oral zinc improves survival in patients with head and neck cancers. Details: Preliminary clinical research in patients with head and neck cancers shows that zinc supplementation does not improve disease-free or metastasis-free survival rates after 3 years when compared with placebo (87103).
Hepatic encephalopathy. It is unclear if oral zinc is beneficial for reducing the severity of hepatic encephalopathy or preventing recurrence. Details: A meta-analysis of small clinical studies, as well as some individual clinical studies, show that short-term zinc supplementation improves cognitive function and possibly quality of life in patients with hepatic encephalopathy. These findings are based on results from the number connection test and other tests (87377,90202,106227). One study in patients with minimal hepatic encephalopathy used zinc bisglycinate 75 mg three times daily, providing elemental zinc 45 mg daily for 12 weeks (106227). However, other preliminary clinical research shows that short-term zinc supplementation does not improve hepatic encephalopathy severity when compared with placebo when assessed using Conn's index, which includes evaluation of mental state, asterixis (flapping tremor), number connection test, electroencephalogram (EEG) record, and plasma ammonia (87144). Also, a meta-analysis of clinical research shows that zinc sulfate supplementation does not reduce encephalopathy recurrence (90202). Based on these results, zinc supplementation may marginally improve cognitive function in hepatic encephalopathy patients, but it does not appear to improve disease severity or reduce the risk of recurrence.
HIV/AIDS-related diarrhea. It is unclear if oral zinc is beneficial for preventing diarrhea in adult HIV patients. Details: Short-term zinc supplementation does not appear to TREAT diarrhea in adult HIV patients with persistent diarrhea. Clinical research shows that taking zinc 50 mg twice daily for 7 days does not reduce the duration of HIV-related diarrhea when compared with placebo (87055). However, zinc supplementation may help PREVENT HIV-related diarrhea when administered long-term. Clinical research shows that taking elemental zinc 12-15 mg daily for 18 months reduces the rate of diarrhea by about half when compared with placebo in adult HIV patients with zinc deficiency (87216). In HIV-infected children, clinical research shows that taking elemental zinc 10 mg daily for 6 months can reduce the occurrence of diarrhea by 49% when compared with placebo (82377). However, administering zinc in combination with vitamin A until 2 years of age does not reduce the occurrence of diarrhea when compared with vitamin A alone in HIV-infected children (82417).
HIV/AIDS-related opportunistic infections. It is unclear if oral zinc is beneficial in opportunistic infections in patients with HIV/AIDs. Details: A small clinical study in patients with AIDS shows that taking zinc supplements orally in combination with zidovudine (AZT, Retrovir) might reduce opportunistic infections of Pneumocystis carinii and Candida when compared with taking zidovudine without zinc (6566).
Human papillomavirus (HPV). It is unclear if oral zinc is beneficial for preventing relapse in patients with vulvar warts or for treating HPV infections and cervical lesions in patients with abnormal cervical cytology. Details: One small clinical study in patients with vulvar warts shows that taking zinc sulfate 400 mg daily for 8 weeks in addition to topical treatments including podophyllin 20%, imiquimod 5%, or cryotherapy, does not affect the duration of response, but does reduce the relapse rate by approximately 66% after 6 months, when compared with topical treatments alone (90190). Additionally, a small, open-label study in zinc-sufficient females with HPV shows that taking zinc sulfate 220 mg twice daily for 3 months reduces the odds of persistent HPV infection by 87% and improves the resolution of pre-existing cervical lesions when compared with no treatment (109456).
Hypertension. It is unclear if oral zinc reduces blood pressure in normotensive or hypertensive patients. Details: A meta-analysis of small clinical trials shows that taking zinc reduces systolic blood pressure by about 1.5 mmHg, but does not reduce diastolic blood pressure, when compared with placebo. Response did not differ with the dosage of zinc or duration of supplementation. Only one study evaluated patients with hypertension; other patient populations included those with type 2 diabetes, diabetic retinopathy, pre-diabetes, obesity, polycystic ovary syndrome (PCOS), and patients on dialysis (104052). More research in patients with hypertension is needed to determine if zinc is beneficial in this population.
Impaired glucose tolerance (prediabetes). While some conflicting evidence exists, several small clinical studies suggest that oral zinc may improve glycemic control in patients with prediabetes. Details: A meta-analysis of three low-quality studies in patients with prediabetes suggests that taking zinc sulfate 20-30 mg, alone or in combination with lysine and vitamin C, for 6-12 months reduces fasting blood glucose and postprandial glucose when compared with control (105682). Furthermore, a small clinical study in patients with prediabetes shows that taking zinc gluconate 30 mg daily for 90 days improves glycemic parameters when compared with placebo. All study participants were also instructed to increase physical activity and start a calorie-restricted diet (105391). However, another small clinical study in patients with prediabetes shows that taking zinc gluconate 30 mg daily for 12 months does not improve glycemic parameters when compared with placebo (109454). The available research has been conducted in Sri Lanka, Bangladesh, Iran, and Australia; it is unclear if these findings are generalizable to other geographic locations.
Intestinal parasite infection. It is unclear if oral zinc is beneficial in patients with intestinal parasitic infections. Details: Zinc supplementation may help TREAT infection from Schistosoma mansoniin, but not other parasites, in children in developing countries. Results from one clinical study show that taking oral zinc sulfate 30-50 mg for 12 months reduces the intensity of Schistosoma mansoniin infection in children, as measured by number of eggs per gram in feces, when compared with placebo (87495). However, supplementation with zinc does not appear to reduce the intensity of Ascaris lumbricoides, Trichiuris trichura, nor Giardia lamblia infection in children (6586). Furthermore, preliminary clinical research suggests that supplementation with zinc may increase the duration of Entamoeba histolytica infection in children (87099). There are also inconsistent results regarding the effects of zinc in PREVENTING intestinal parasite infections. Some clinical research shows that taking zinc in combination with vitamin A reduces the incidence of Giardia lamblia infections when compared with placebo (87099). However, zinc supplementation does not appear to prevent intestinal infections by Ascaris lumbricoides, Schistosoma haematobium, nor Schistosoma mansoniin (87099,87495).
Kidney failure. It is unclear if oral zinc is beneficial for patients on hemodialysis who have resistance to erythropoiesis-stimulating agents (ESAs). Details: Zinc deficiency is thought to play a role in ESA-resistant anemia in patients with kidney failure. A small clinical trial in patients on hemodialysis with low zinc levels shows that taking zinc acetate hydrate, usually 25mg or 50 mg daily, for 12 months increases plasma levels of zinc and modestly reduces the required weekly dose of ESAs when compared with placebo. However, there was no effect on hemoglobin levels (109781).
Leukemia. It is unclear if oral zinc is beneficial for improving weight maintenance in children and adolescents with leukemia. Details: A small clinical study in children and adolescents with acute leukemia shows that taking zinc 2 mg/kg (as an amino acid salt) in two divided doses daily for 60 days doubles weight gain and reduces infection rate by approximately 60% when compared with placebo. However, zinc supplementation does not appear to improve nutritional status (90204).
Liver cancer. It is unclear if oral zinc is beneficial for preventing hepatocellular carcinoma (HCC). Details: In patients treated for hepatitis C, the presence of hepatic fibrosis increases the risk for development of HCC, and is also associated with low plasma zinc levels. In a retrospective analysis of patients with a sustained virological response to hepatitis C therapy, those taking oral zinc supplements for at least 6 months had approximately half the risk of developing HCC when compared with those not taking zinc. Maintaining a serum zinc level above 90 mcg/dL seems to reduce the risk for HCC (106904).
Lung cancer. It is unclear if increased dietary zinc intake is beneficial for reducing the risk of lung cancer. Details: Population research suggests that the highest dietary intake of zinc is associated with a 32% reduced risk of lung cancer when compared with the lowest intake (106235). Additionally, another large epidemiological cancer screening trial with a mean follow-up of 12.2 years suggests that dietary intake of zinc is protective against lung cancer, with the highest quartile of dietary intake showing the greatest benefit. However, this protective effect was not found for supplemental intake of zinc (112096).
Male infertility. It is unclear if oral zinc is beneficial for infertility in males. Details: Some preliminary clinical research shows that taking zinc sulfate 66 mg daily increases sperm count, testosterone levels, and the incidence of pregnancy in idiopathic infertile men with low testosterone levels (9334,87430). Another clinical study shows that taking zinc sulfate 66 mg daily can improve sperm morphology by approximately 33% when compared to baseline in men with a grade III varicocele (90194). However, not all research agrees. One clinical study shows that taking elemental zinc 30 mg with folic acid 5 mg daily for 6 months does not improve sperm morphology or pregnancy rates when compared with placebo in infertile men (102085). It is possible the lower dose used in this study was insufficient to produce the beneficial effects observed in earlier research. Zinc supplementation has also been studied as part of combination therapy. A retrospective study in males with or without varicocele-related infertility has found that taking a specific combination product containing zinc 10 mg, L-carnitine fumarate 1725 mg, acetyl-L-carnitine 500 mg, vitamin C 90 mg, coenzyme Q10 20 mg, folic acid 0.2 mg, selenium 0.05 mg, and vitamin B12 0.015 mg (Proxeed Plus, Sigma-Tau) orally twice daily for 6 months improves sperm count, sperm concentration, and sperm motility when compared with baseline. Improvements in semen parameters were greatest in subjects with more severe varicoceles. The validity of this study is limited by the lack of a comparator group (111296). There is also interest in using zinc to improve results of in vitro fertilization (IVF). A small clinical study in couples undergoing IVF suggests that infertile male partners who take a specific combination product (Menevit) containing zinc and other antioxidants seem to have an increased rate of viable pregnancies when compared with placebo (87087). However, it's unclear if the benefit can be attributed to zinc, other antioxidants, or the combination.
Melasma. It is unclear if topical zinc reduces melasma severity. Details: A small clinical study shows that applying a topical solution containing zinc sulfate 10% once daily for 2 months is less effective at reducing melasma severity when compared with hydroquinone 4% (90232).
Menopausal symptoms. It is unclear if oral zinc improves sexual function after menopause. Details: A single clinical trial shows that taking zinc sulfate 110 mg daily for 6 weeks modestly improves testosterone levels and sexual function, including desire, arousal, satisfaction, and pain, after menopause when compared with placebo (106228).
Migraine headache. It is unclear if oral zinc is beneficial in patients with migraine. Details: Two small clinical studies in patients with migraine show that taking zinc sulfate 200 mg or zinc gluconate 15 mg daily for 8-12 weeks modestly reduces migraine severity and frequency when compared with placebo (104040,105684). Both studies were conducted in Iran; it is unclear if these findings are generalizable to other geographic locations.
Nasopharyngeal cancer. It is unclear if oral zinc is beneficial in patients with this type of cancer. Details: A small clinical study in patients with locally advanced nasopharyngeal cancer shows that zinc supplementation 75 mg daily for 2 months may improve disease-free survival rates after 5 years when compared with placebo (87163).
Neonatal jaundice. It is unclear if oral zinc is beneficial for neonatal jaundice. Details: There is contradictory evidence about the effects of oral zinc in infants with hyperbilirubinemia. Two small clinical studies in infants with idiopathic neonatal hyperbilirubinemia show that receiving oral zinc sulfate 5 mg twice daily for 5-7 days does not affect levels of total bilirubin, the required duration of phototherapy, or the duration of hospitalization, when compared with placebo (90212,104814). However, a larger clinical trial in preterm infants receiving phototherapy and zinc 1.2 mg/kg daily as zinc sulfate heptahydrate, via either orogastric or nasogastric tube for 10 days, serum bilirubin levels were modestly decreased only on days 8-10 when compared with phototherapy alone (106242). Additionally, a second larger clinical trial in infants with idiopathic hyperbilirubinemia shows that receiving oral zinc sulfate (Zinc sulfate, Ramofarmin Company) 1 mg/kg daily for 3 days reduces total bilirubin levels and duration of phototherapy when compared with placebo; additionally length of hospitalization is reduced by less than 1 day (115631). The reason for these discrepant findings is unclear but may be attributed to variations in baseline characteristics, treatment duration, and dose.
Nonalcoholic fatty liver disease (NAFLD). It is unclear if oral zinc is beneficial in patients with NAFLD. Details: A small clinical study in patients with NAFLD shows that following a calorie-restricted diet and taking zinc 30 mg daily for 12 weeks reduces certain liver enzymes, but does not improve steatosis or reduce weight, when compared with taking placebo and following a calorie-restricted diet (104046).
Non-Hodgkin lymphoma. It is unclear if oral zinc is beneficial for non-Hodgkin lymphoma prevention. Details: Population research has found that higher dietary intake of zinc is associated with a 42% decreased odds of developing non-Hodgkin lymphoma (87048).
Obesity. Small studies suggest that oral zinc does not reduce weight or calorie intake in people with overweight or obesity. Details: A very small clinical study in adults with overweight or obesity shows that taking supplemental zinc 30 mg daily for 12 weeks does not reduce body weight, body mass index (BMI), calorie intake, or macronutrient intake when compared with placebo (112471). Additionally, clinical research in adults with overweight or obesity shows that taking zinc gluconate 25 mg and L-selenomethionine 200 mcg once daily for 8 weeks does not improve BMI, total body fat, or fat free mass when compared with placebo (111448).
Obsessive-compulsive disorder (OCD). It is unclear if oral zinc reduces symptoms in patients with OCD. Details: A small clinical study in patients with OCD shows that taking zinc sulfate 200 mg twice daily with fluoxetine 20 mg daily for 8 weeks modestly reduces the severity of OCD symptoms when compared with taking placebo with fluoxetine (90223).
Oral mucositis. It is unclear if oral or topical zinc prevents oral mucositis due to chemotherapy. Some small clinical studies suggest that oral zinc might prevent mucositis due to radiotherapy. Details: Two small clinical studies in adults with leukemia and other cancers shows that taking zinc sulfate 220 mg three times daily for 14 days or until the end of chemotherapy treatment reduces oral mucositis and pain intensity when compared with placebo (90191,98132). However, smaller doses have not shown benefit. A small clinical study in children and adolescents with leukemia shows that taking zinc 2 mg/kg daily (up to 60 mg daily) in two divided doses does not affect chemotherapy-induced mucositis when compared with placebo (90204). An unblinded clinical study in children and adolescents aged 8-16 years with recently diagnosed leukemia shows that taking zinc gluconate 50 mg (7 mg elemental zinc) daily does not significantly reduce the incidence or duration of oral mucositis when compared with a control group not receiving zinc (104816). Zinc also doesn't seem to be beneficial with high-dose chemotherapy. A small clinical study in adolescents and adults receiving high-dose chemotherapy prior to undergoing hematopoietic stem cell transplantation (HSCT) suggests that taking zinc sulfate 220 mg (50 mg elemental zinc) twice daily, beginning one day prior to the chemotherapy regimen and continuing for 3 weeks, does not affect the severity, duration, or onset of mucositis when compared with placebo (90215). Other preliminary clinical research in children aged 3-18 years receiving chemotherapy for leukemia or other cancer also shows that taking zinc 1 mg/kg orally daily for 14 days, beginning on the first day of chemotherapy, does not reduce the incidence or severity of mucositis when compared with placebo (111447). Topical zinc has also been investigated for radiation-induced or chemotherapy-induced oral mucositis. In two clinical studies, using 7.5 mL of a mouthwash containing zinc chloride 0.2% twice for 2 minutes every 8 hours for 3 weeks modestly reduces the incidence and severity of oral mucositis, and improves quality of life, when compared with a placebo mouthwash (106232,109690). In one study, the average patient weight was higher in the group using the mouthwash containing zinc (106232). Other preliminary clinical research in adults with head and neck cancer undergoing radiotherapy treatment, consisting of at least 30 Gy radiation exposure shows that using zinc sulfate 1% mouthwash, 5 mL three times daily for 6 weeks, beginning on the first day of radiation therapy, moderately improves oral mucositis severity and pain scores when compared with chlorhexidine 0.2% or placebo mouthwash (111291). Taking zinc orally might be beneficial in radiation-induced oral mucositis. A small clinical study in patients with head and neck tumors shows that taking zinc sulfate, providing 150 mg elemental zinc, daily starting at the first day of radiation therapy and ending at 6 weeks, reduces the severity of mucositis and prolongs the onset of mucositis when compared with placebo (86981). Another clinical study in patients with head and neck cancer shows that taking zinc sulfate 150 mg daily during and after chemoradiotherapy treatment, consisting of a total 69.5 Gy radiation exposure and cisplatin 40 mg/m2 weekly, is associated with less severe mucositis when compared with placebo (105677).
Osteoporosis. It is unclear if oral zinc improves bone density in patients with osteoporosis. Details: Population research has found that reduced zinc intake and lower zinc serum levels seem to be associated with lower bone mineral density (BMD) (6920,14410). In elderly patients with at least marginal zinc deficiency who are taking standard therapy for osteoporosis, preliminary clinical research shows that taking zinc acetate dihydrate (Nobelzin, Nobelpharma) providing elemental zinc 25 mg twice daily for 12 months increases BMD when compared with baseline. Increases in serum zinc were associated with improvements in BMD. However, it is unclear if increases in BMD were significant when compared with placebo (106230). It is also unclear if zinc improves BMD in patients without zinc deficiency. A small clinical study in healthy postmenopausal adults suggests that taking zinc in combination with copper, manganese, and calcium might slow bone loss when compared with placebo (1994). It is not clear if this effect is due to zinc, other ingredients, or the combination.
Overall mortality. It is unclear if oral zinc reduces overall mortality in young children. Details: A meta-analysis of clinical research in children under the age of five years shows that supplementation with zinc in daily doses of at least 10 mg reduces the risk of all-cause mortality by 16% when compared with either placebo, other vitamin and/or mineral supplementation, or no supplementation. The risk of mortality was reduced by 54% when children took zinc for up to one year, but overall mortality was not reduced in studies lasting at least one year (106239).
Periodontitis. Oral zinc has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in patients with moderate or advanced periodontitis shows that taking a combination supplement containing zinc 3.75 mg, alpha-lipoic acid, coenzyme Q10, cranberry extract, grapeseed extract, selenium, vitamin C, and vitamin E twice daily for 8 weeks in addition to standard nonsurgical therapy does not reduce periodontal indices including bleeding on probing, gingival recession, plaque index, or inflammation when compared with placebo (111708).
Polycystic ovary syndrome (PCOS). It is unclear if oral zinc is beneficial in patients with PCOS. Details: A small clinical study in adults taking metformin for PCOS shows that also taking zinc sulfate 220 mg (50 mg elemental zinc) daily for 8 weeks improves hair loss and facial growth, but not acne, when compared with placebo (96071).
Postoperative sore throat. It is unclear if oral zinc is beneficial for postoperative sore throat. Details: Clinical research shows that dissolving a lozenge containing zinc 40 mg as zinc sulfate in the mouth in the 30 minutes before surgery involving endotracheal intubation reduces the incidence of postoperative sore throat by 58% when compared with placebo lozenges. It also seems to reduce the severity of postoperative sore throat that does occur (97138). Other clinical research in adults undergoing a procedure that required endotracheal intubation shows that using a preoperative 30-mL gargle containing zinc 40 mg does not affect sore throat scores when compared with magnesium sulphate 250 mg or budesonide 200 mcg gargles (114763).
Postpartum depression. It is unclear if oral zinc prevents postpartum depression after a Cesarean section (C-section). Details: A small observational study in pregnant patients with anemia who underwent C-section has found that taking zinc sulfate 100 mg daily for 4 days after surgery is associated with a 75% reduction in the odds of developing postpartum depression when compared with no supplementation (109452).
Premenstrual syndrome (PMS). It is unclear if oral zinc improves symptoms in patients with PMS. Details: A small clinical study in female college students shows that taking elemental zinc 30 mg daily for 3 months improves quality of life, but not quality of sleep, when compared with placebo (104049).
Preterm labor. It is unclear if oral zinc reduces the risk of preterm labor. Details: Observational research has found that low dietary intake of zinc during pregnancy is associated with an increased likelihood of preterm deliveries (87471). Also, most meta-analyses of clinical research show that taking zinc supplements during pregnancy modestly reduces the risk of preterm birth (106231). However, one large meta-analysis of 22 clinical studies shows that zinc supplementation during pregnancy seems to have little or no benefit for reducing the risk of preterm birth when compared with control (105679). Zinc supplementation also does not seem to reduce the risk of stillbirth, neonatal death, spontaneous abortion, or premature rupture of membranes (97142,105679,106231).
Prostatitis. It is unclear if oral zinc improves symptoms in men with chronic prostatitis. Details: A clinical study in men with chronic prostatitis shows that taking zinc sulfate 220 mg daily along with prazosin 2 mg daily for 12 weeks does not improve difficulty urinating or quality of life, but does seem to improve pain, when compared with prazosin alone (90210). The validity of this study was limited by a significant dropout rate.
Pruritus. There is limited evidence on the oral use of zinc for reducing pruritis in hemodialysis patients. Details: A small clinical study in end-stage renal disease patients with hemodialysis-associated pruritus shows that taking zinc sulfate 220 mg twice daily for 2 months reduces pruritus severity when compared with placebo (90218).
Psoriatic arthritis. It is unclear if oral zinc improves psoriatic arthritis symptoms. Details: Two small clinical trials in patients with psoriatic arthritis show that taking zinc orally, alone or in combination with nonsteroidal anti-inflammatory drugs (NSAIDs), does not seem to reduce pain or improve function when compared with control (6514,6515).
Respiratory tract infections. It is unclear if oral zinc reduces respiratory tract infections in children. Details: An open-label study in children aged 6 months to 5 years with zinc deficiency shows that taking zinc sulfate 20 mg orally once daily for 2 weeks reduces the number of episodes and the mean duration of upper and lower respiratory tract infections over 6 months of follow-up when compared with the 6 months prior to zinc supplementation (104815). The validity of this finding is limited by the lack of a comparator group.
Rosacea. It is unclear of oral zinc improves symptoms of rosacea or quality of life. Details: A small clinical trial shows that taking zinc sulfate 440 mg in two divided doses daily for 90 days does not improve quality of life or symptoms associated with rosacea when compared with placebo (90195).
Seizures. It is unclear if oral zinc reduces recurrent febrile seizures in children. Details: Although some individual preliminary clinical research disagrees (96069), a meta-analysis of generally low-quality research in children under 5 years of age with a previous febrile seizure shows that taking zinc sulfate 1-2 mg/kg or 20 mg daily for 6-12 months does not reduce febrile seizure recurrence when compared with placebo (106237). Also, a small clinical study shows that taking zinc does not increase the time to first febrile seizure recurrence (96069).
Sepsis. It is unclear if oral zinc is beneficial in pediatric or adult patients with sepsis. Details: A meta-analysis of clinical research in children under the age of five years shows that supplementation with zinc reduces the risk of sepsis mortality by 57% when compared with either placebo, other vitamin and/or mineral supplementation, or no supplementation (106239). Also, a small clinical study in newborns with sepsis shows that giving zinc sulfate monohydrate 3 mg/kg twice daily for 10 days along with antibiotics reduces the likelihood of neurological abnormalities, such as those related to posture, behavior, and reflexes, by 70% when compared with antibiotics alone. Mortality and length of hospital stay were not improved, but the study may have been inadequately powered to detect a difference in these parameters (96077). Another study in preterm infants with late-onset sepsis (developing at least 72 hours after birth), shows that giving 1.4 mg/kg elemental zinc daily orally for 10 days in addition to antibiotics reduces the number of infants with unresolved sepsis at 10 days, and reduces C-reactive protein and procalcitonin levels, when compared with giving antibiotics alone (104819). A meta-analysis of small clinical studies in infants less than 4 months old shows that administering zinc 1-3 mg/kg daily for 1-18 weeks may reduce the rate of infant mortality and treatment failure when compared with placebo or control, but does not seem to prevent sepsis or improve sepsis-related mortality (108444). Additionally, zinc has been evaluated in adults. A single-center observational study in adults with sepsis found that administering zinc orally or enterally in various doses, ranging from less than 15 mg to greater than 50 mg daily, does not improve survival rates or reduce the length of stay in the intensive care unit (115630).
Shigellosis. It is unclear if oral zinc is beneficial in patients with acute shigellosis from food poisoning. Details: A small clinical study in malnourished children with acute shigellosis (food poisoning) shows that administering a multivitamin syrup containing elemental zinc 20 mg daily for 2 weeks, in addition to standard treatment, can improve recovery time and reduce the number of diarrhea episodes when compared with multivitamin syrup without elemental zinc (87088).
Sleep deprivation. Oral zinc has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A very small clinical study in sleep-deprived recreational athletes shows that taking a combination of zinc 90 mg, magnesium 1350 mg, and vitamin B6 31.5 mg orally for 3 nights at bedtime does not change sleep quality, subjective sleepiness, mood, or fatigue when compared with placebo (113655).
Substance use disorder. It is unclear if oral zinc is beneficial for substance use disorder. Details: Preliminary clinical research in adults with opioid use disorder that were being treated with methadone shows that taking zinc sulfate, containing 12 mg zinc, orally daily for 3 months moderately improves relapse prevention scores, including drug use and drug craving scores, when compared with control. Taking zinc also modestly improved stress and anxiety scores (111293).
Tonsillopharyngitis. It is unclear if oral zinc is beneficial in patients with tonsillopharyngitis. Details: A moderate-sized, open-label clinical study in pediatric patients aged 3 to 10 years with acute tonsillopharyngitis shows that taking a specific combination solution (PediaFlù, Pediatrica S.r.l.) containing zinc (age dependent doses ranging from 2 to 4 mg), honey, propolis, and pelargonium sidoides daily for 6 days along with standard of care reduces tonsilitis severity scores when compared with standard care alone; however, this improvement is not clinically significant. (115632). It is not clear if these effects are due to zinc, other ingredients, or the combination.
Traumatic brain injury (TBI). There is limited evidence on the parenteral use of zinc for closed head injury. Details: A small clinical study shows that administering zinc parenterally immediately following severe closed head injury seems to improve the rate of neurological recovery when compared with standard therapy (2696).
Tuberculosis. It is unclear if oral zinc can improve outcomes in patients receiving tuberculosis treatment. Details: Low levels of zinc are common in patients with tuberculosis. In patients newly diagnosed with tuberculosis and using anti-tuberculosis treatment, some clinical research shows that taking zinc 50 mg daily as zinc sulfate for 6 months increases the number of patients with negative sputum smears by 50% to 80% within the first 6 weeks of treatment when compared with placebo. However, there were no differences in the number of patients with negative smears after this time point. There were also improvements in some liver function enzyme levels after 2 months, but not 6 months, when compared with placebo (106238). However, other clinical research shows that taking zinc 15-90 mg daily for 2-6 months does not improve cure rates or sputum smear conversions when compared with placebo. However, when combined with vitamin A, serum levels of vitamin A, zinc, and hemoglobin were modestly improved and there was a modest increase in sputum smear conversions (109754).
Urinary tract infections (UTIs). It is unclear if oral zinc is beneficial in children with UTI. Details: A low-quality, clinical study in children aged 3-12 years hospitalized for a UTI and receiving intravenous antibiotic treatment shows that taking zinc 1 mg/kg daily for 14 days reduces the duration of dysuria, urinary frequency, and urgency when compared with intravenous antibiotics alone. Zinc does not improve fever or the time to negative urine culture (96081). However, this study did not demonstrate that treatment groups were equal at baseline.
Venous leg ulcers. It is unclear if oral or topical zinc is beneficial for leg ulcer healing. Details: Two small studies in elderly patients with leg ulcers suggest that using a zinc saline solution on a wound dressing or applying zinc oxide to a dressing might improve healing of leg ulcers (2694,6901). However, oral zinc supplementation does not seem to be beneficial. A meta-analysis of four small clinical trials in patients with venous leg ulcers shows that taking zinc orally does not improve healing when compared with placebo (104079).
Vertigo. Oral zinc has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in adults with benign paroxysmal positional vertigo with serum 25-hydroxyvitamin D levels less than 20 ng/mL shows that taking a specific combination product containing zinc 7.5 mg, alpha-lipoic acid 600 mg, L-carnosine 165 mg, curcumin 100 mg, piperine 1 mg, cholecalciferol 800 units, vitamin B2 0.8 mg, and vitamin B6 1 mg (Vertistop D, Difass) orally daily for 6 months moderately reduces the number of vertigo relapse episodes when compared with control. However, in patients with serum 25-hydroxyvitamin D levels greater than 20 ng/mL that took a specific combination product containing zinc 7.5 mg, alanine 600 mg, L-carnosine 165 mg, curcumin 100 mg and piperine 1 mg (Vertistop L, Difass) orally daily for 6 months there was no difference in relapse episodes when compared with control (111294). It is unclear if this effect is due to zinc, other ingredients, or the combination.
Water warts. It is unclear if oral zinc is beneficial for the treatment of water warts in children. Details: In children with water warts, preliminary clinical research shows that taking zinc sulfate heptahydrate (as Zinco syrup) for 2 months results in lesion resolution in 70% of patients when compared with baseline. Lesion resolution occurred in an additional 13% of patients in the month after treatment completion, with no recurrence in any of these children over the next 9 months. Zinc 3 mg daily was used in children up to 3 years of age, and 5 mg daily was used in older children (106234). Due to the lack of a comparator group, it is unclear if these outcomes are due to zinc or the natural resolution of the condition.
Wound healing. Topical zinc might be beneficial for the healing of uncomplicated wounds. Details: A small clinical study shows that applying zinc chloride solution, standardized to contain zinc 20 mcg/mL, twice daily improves wound healing when compared with saline solution in patients with uncomplicated, skin wounds. However, when zinc is administered as a component of an insulin product (Humulin, Eli Lilly and Company), it seems to be more effective than zinc chloride alone (90192).
Wrinkled skin. Topical zinc has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A topical preparation containing 10% vitamin C as L-ascorbic acid and acetyl tyrosine, zinc sulfate, sodium hyaluronate, and bioflavonoids (Cellex-C High Potency Serum) applied to photo-aged facial skin for 3 months seems to improve fine and coarse wrinkling, yellowing and sallowness, roughness, and skin tone when compared with placebo (6155). More evidence is needed to rate zinc for these uses.

Safety view details

Below is general information about the safety of the known ingredients contained in the product Supreme DHEA for Intimacy. Some ingredients may not be listed. This information does NOT represent a recommendation for or a test of this specific product as a whole.

DAMIANA

LIKELY SAFE ...when used orally in amounts commonly found in foods. Damiana has Generally Recognized As Safe status (GRAS) for use in foods in the US (4912).

POSSIBLY SAFE ...when used orally and appropriately in medicinal amounts (12,46933,11866).

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

POSSIBLY SAFE ...when used orally and appropriately, short-term. Most studies have been small and lasted from a few weeks to 6 months, with usual doses of 50 mg daily (793,1635,2133,3231,4249,4251,4252,4253,4254,4255,9691)(9692,10986,12215,12564,14277,21416,88726,90304,99925). Some studies have also used oral DHEA with apparent safety for 12-24 months (2113,6446,10406,11464,12561,15027,88492). ...when used intravaginally and appropriately. Intravaginal ovules of DHEA 3.25 mg to 13 mg have been safely used for up to 12 weeks (21320,21429,21430). ...when used topically and appropriately. A DHEA cream 1% to 10% has been safely used for up to 12 months (4242,21428).

POSSIBLY UNSAFE ...when used orally in high doses or long-term. There is concern that long-term use or use of amounts that cause higher than normal physiological DHEA levels might increase the risk of prostate cancer (2111,12565), breast cancer (10370,10401,10403), or other hormone-sensitive cancers (6445). In some cases, 50-100 mg daily can produce slightly higher than normal physiological DHEA levels (4249,4251). There is insufficient reliable information available about the safety of using DHEA intravenously or intramuscularly.

PREGNANCY AND LACTATION: POSSIBLY UNSAFE
when used orally. DHEA can cause higher than normal androgen levels (2133,4249,4251,4253), which might adversely affect pregnancy or a nursing infant.

LIKELY SAFE ...when used orally and appropriately in food amounts (4960,4969,5792,5797). Oat bran has Generally Recognized as Safe (GRAS) status in the US (4912). Whole grain oats 50-100 grams daily have been used for up to 1 year without serious adverse effects (97520).

POSSIBLY SAFE ...when used topically and appropriately (12). Lotion containing colloidal oat 1% has been used topically without adverse effects for up to 6 weeks (97518,103340). There is insufficient reliable information available about the safety of oats when used orally in medicinal amounts.

PREGNANCY AND LACTATION: LIKELY SAFE
when used orally in food amounts (5792,5797).

SARSAPARILLA

LIKELY SAFE ...when used orally in amounts commonly found in foods. Sarsaparilla has Generally Recognized As Safe (GRAS) status for use in foods in the US (4912). There is insufficient reliable information available about the safety of sarsaparilla when taken orally in medicinal amounts.

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

SAW PALMETTO

LIKELY SAFE ...when used orally and appropriately. Saw palmetto has been safely used in clinical studies lasting up to 3 years (2735,6750,6752,6764,6772,6773,11354,14274,15550,17202,17306,17684,73315,73383,73384,73385,73389,89441,96410,96412,110540).

POSSIBLY SAFE ...when used rectally and appropriately. Saw palmetto has been used safely in clinical research at a dose of 640 mg once daily for 30 days (73387). However, the long-term safety of saw palmetto administered rectally is not known.

PREGNANCY AND LACTATION: LIKELY UNSAFE
when used orally. Saw palmetto has hormonal activity (6766); avoid using.

POSSIBLY SAFE ...when used orally and appropriately. Stinging nettle root 360-600 mg has been used safely for up to 1 year (5093,11230,15195,76406,96744). ...when used topically and appropriately (12490).

PREGNANCY: LIKELY UNSAFE
when used orally due to possible abortifacient and uterine-stimulant effects (4,6,19).

LACTATION:
Insufficient reliable information available; avoid using.

YOHIMBE

POSSIBLY UNSAFE ...when used orally. Yohimbine, a constituent of yohimbe, has been associated with serious adverse effects including cardiac arrhythmia, agitation, myocardial infarction, seizure, and others (17465). Some research shows that yohimbine can be safely used under close medical supervision for up to 10 weeks (3305,3307,3311,3313). However, due to safety concerns, yohimbe should not be used without medical supervision.

PREGNANCY AND LACTATION: POSSIBLY UNSAFE
when used orally. Yohimbe might have uterine relaxant effects and also cause fetal toxicity (19).

ZINC

LIKELY SAFE ...when used orally and appropriately. Zinc is safe in amounts that do not exceed the tolerable upper intake level (UL) of 40 mg daily (7135). ...when used topically and appropriately (2688,6538,6539,7135,8623,11051,111291).

POSSIBLY SAFE ...when used orally and appropriately in doses higher than the tolerable upper intake level (UL). Because the UL of zinc is based on regular daily intake, short-term excursions above 40 mg daily are not likely to be harmful. In fact, there is some evidence that doses of elemental zinc as high as 80 mg daily in combination with copper 2 mg can be used safely for approximately 6 years without significant adverse effects (7303,8622,92212). However, there is some concern that doses higher than the UL of 40 mg daily might decrease copper absorption and result in anemia (7135).

POSSIBLY UNSAFE ...when used intranasally. Case reports and animal research suggest that intranasal zinc might cause permanent anosmia or loss of sense of smell (11155,11156,11703,11704,11705,11706,11707,16800,16801,17083). Several hundred reports of anosmia have been submitted to the US Food and Drug Administration (FDA) and the manufacturer of some intranasal zinc products (Zicam) (16800,16801). Advise patients not to use intranasal zinc products.

LIKELY UNSAFE ...when taken orally in excessive amounts. Ingestion of 10-30 grams of zinc sulfate can be lethal in adults (7135). Chronic intake of 450-1600 mg daily can cause multiple forms of anemia, copper deficiency, and myeloneuropathies (7135,17092,17093,112473). This has been reported with use of zinc-containing denture adhesives in amounts exceeding the labeled directions, such as several times a day for several years (17092,17093). Advise patients to follow the label directions on denture adhesives that contain zinc.

CHILDREN: LIKELY SAFE
when used orally and appropriately (7135). Zinc is safe in amounts that do not exceed the tolerable upper intake level (UL). The UL for children is based on age: 4 mg daily for 0-6 months, 5 mg daily for 7-12 months, 7 mg daily for 1-3 years, 12 mg daily for 4-8 years, 23 mg daily for 9-13 years, and 34 mg daily for 14-18 years (7135,97140).

CHILDREN: POSSIBLY UNSAFE
when used orally in high doses. Taking amounts greater than the UL can cause sideroblastic anemia and copper deficiency (7135). ...when used topically on damaged skin. An infant treated with 10% zinc oxide ointment for severe diaper rash with perianal erosions developed hyperzincemia. Absorption seemed to occur mainly via the erosions; plasma levels dropped after the erosions healed despite continued use of the ointment (106905).

PREGNANCY: LIKELY SAFE
when used orally and appropriately. Zinc is safe in amounts that do not exceed the tolerable upper intake level (UL) of 34 mg daily during pregnancy in those 14-18 years of age and 40 mg daily in those 19-50 years of age (7135).

PREGNANCY: LIKELY UNSAFE
when used orally in doses exceeding the UL (7135).

LACTATION: LIKELY SAFE
when used orally and appropriately. Zinc is safe in amounts that do not exceed the tolerable upper intake level (UL) of 34 mg daily during lactation in those 14-18 years of age, and 40 mg daily for those 19-50 years of age (7135).

LACTATION: POSSIBLY UNSAFE
when used orally in doses exceeding the UL. Higher doses can cause zinc-induced copper deficiency in nursing infants (7135).

Interactions with Drugs view details

Below is general information about the interactions of the known ingredients contained in the product Supreme DHEA for Intimacy. Some ingredients may not be listed. This information does NOT represent a recommendation for or a test of this specific product as a whole.

DAMIANA

ANTIDIABETES DRUGS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = D

Theoretically, taking damiana with antidiabetes drugs might increase the risk of hypoglycemia.

Details

Animal research shows that taking damiana lowers blood glucose level (4,25016).

ANTICOAGULANT/ANTIPLATELET DRUGS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = D

Theoretically, DHEA might increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.

Details

Human and laboratory research show that DHEA and DHEA-S can inhibit platelet aggregation (19109,19127).

ANTIDEPRESSANT DRUGS

Interaction Rating = Moderate Be cautious with this combination.

Severity = High • Occurrence = Possible • Level of Evidence = D

Theoretically, DHEA might increase the risk of psychiatric adverse events when used with antidepressants.

Details

In a human case report, the use of a selective serotonin reuptake inhibitor (SSRI) with DHEA caused a manic episode (7023). Concern for this interaction may be greater in younger individuals with higher baseline DHEA levels.

AROMATASE INHIBITORS

Interaction Rating = Moderate Be cautious with this combination.

Severity = High • Occurrence = Possible • Level of Evidence = D

Theoretically, DHEA might interfere with the clinical effects of aromatase inhibitors.

Details

DHEA is a potent estrogen agonist, which may antagonize the anti-estrogen activity of aromatase inhibitors (10401).

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = D

Theoretically, DHEA might increase the levels of drugs metabolized by CYP3A4.

Details

Some preliminary evidence shows that DHEA may inhibit CYP3A4 (1389); however, the clinical significance of this potential interaction is not known.

ESTROGENS

Interaction Rating = Minor Be watchful with this combination.

Severity = Mild • Occurrence = Possible • Level of Evidence = D

Theoretically, DHEA might increase the effects and adverse effects of estrogen therapy.

Details

DHEA is a precursor to estrogen and androgen and is metabolized into those substances. In clinical research, DHEA supplements increase the levels of these hormones (6012,7614,8593,10986,12651,12564,15027,21321,21323,21324)(21325,21326,21327,21328,21330,21331,21356,21364,21389,21393)(21397,21398,21417,21419,21427,47273,47348,88375,90304). Also, in clinical research, estrogen-progestin oral contraceptives and conjugated estrogens reduce blood levels of DHEA and DHEA-S (21372,21373,21374,21437,21438). The clinical significance of these findings is unclear.

FULVESTRANT (Faslodex)

Interaction Rating = Moderate Be cautious with this combination.

Severity = High • Occurrence = Possible • Level of Evidence = D

Theoretically, DHEA might interfere with the anti-estrogen effects of fulvestrant.

Details

DHEA is a potent estrogen agonist (10401). Some research shows that it can overcome the estrogen receptor antagonist action of fulvestrant in estrogen-receptor positive cancer cells (10370).

TAMOXIFEN (Nolvadex)

Interaction Rating = Moderate Be cautious with this combination.

Severity = High • Occurrence = Possible • Level of Evidence = D

Theoretically, DHEA might interfere with the anti-estrogen effects of tamoxifen.

Details

DHEA is a potent estrogen agonist. Some research shows that it can overcome the estrogen receptor antagonist activity of tamoxifen in estrogen-receptor positive cancer cells (10370,10403).

TESTOSTERONE

Interaction Rating = Minor Be watchful with this combination.

Severity = Mild • Occurrence = Possible • Level of Evidence = D

Theoretically, DHEA might increase the effects and side effects of testosterone therapy.

Details

DHEA is a precursor to estrogen and androgen and is metabolized into those substances. In clinical research, DHEA supplements increase the levels of these hormones (6012,7614,8593,10986,12651,12564,15027,21321,21323,21324)(21325,21326,21327,21328,21330,21331,21356,21364,21389,21393)(21397,21398,21417,21419,21427,47273,47348,88375,90304,99924,99925,104162). The clinical significance of these findings is unclear.

TRIAZOLAM (Halcion)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = D

DHEA can increase blood levels of triazolam.

Details

Administration of DHEA 200 mg daily for two weeks was shown to inhibit the cytochrome P450 3A4 (CYP3A4) metabolism of triazolam. This inhibition appears to be due to DHEA-S, rather than DHEA (1389).

TUBERCULOSIS VACCINE

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = D

DHEA might reduce the effectiveness of the tuberculosis vaccine.

Details

Animal research shows that high doses of DHEA can reduce the efficacy of the Bacillus Calmette-Guérin (BCG) tuberculosis vaccine (21316).

ANTIDIABETES DRUGS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = D

Theoretically, oats may have additive effects with antidiabetic agents and might increase the risk of hypoglycemia.

Details

Consuming oats can decrease blood glucose in patients with diabetes (4980,4982,6266,103345). In those who require insulin, taking oats 100 grams daily for 2 days reduces the insulin dose required to achieve metabolic control (103336).

INSULIN

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = B

Concomitant use of oats and insulin might increase the risk of hypoglycemia.

Details

In patients with insulin-dependent type 2 diabetes, taking oats 100 grams daily for 2 days reduces the insulin dose required to achieve metabolic control (103336).

SARSAPARILLA

DIGOXIN (Lanoxin)

Interaction Rating = Moderate Be cautious with this combination.

Severity = High • Occurrence = Possible • Level of Evidence = D

Theoretically, concomitant use of sarsaparilla with digoxin might increase the risk of cardiac toxicity.

Details

Sarsaparilla is thought to have diuretic properties, which could potentially cause potassium loss. Overuse or misuse of sarsaparilla with cardiac glycoside therapy might increase the risk of cardiac toxicity due to potassium loss (2,11).

LITHIUM

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = D

Theoretically, sarsaparilla might increase the effects and adverse effects of lithium.

Details

Sarsaparilla is thought to have diuretic properties (11). Due to these effects, sarsaparilla might reduce excretion and increase levels of lithium. The dose of lithium might need to be decreased.

SAW PALMETTO

ANTICOAGULANT/ANTIPLATELET DRUGS

Interaction Rating = Moderate Be cautious with this combination.

Severity = High • Occurrence = Possible • Level of Evidence = D

Saw palmetto might increase the risk of bleeding with anticoagulant or antiplatelet drugs.

Details

Saw palmetto is reported to prolong bleeding time (8659). Theoretically, it might increase the risk of bleeding when used concomitantly with anticoagulant or antiplatelet drugs.

CONTRACEPTIVE DRUGS

Interaction Rating = Moderate Be cautious with this combination.

Severity = High • Occurrence = Possible • Level of Evidence = B

Saw palmetto might reduce the effectiveness of contraceptive drugs.

Details

Saw palmetto might have antiestrogenic effects (6766). Theoretically, it might interfere with contraceptive drugs taken concomitantly.

ESTROGENS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = B

Saw palmetto might reduce the effectiveness of estrogens.

Details

Saw palmetto might have antiestrogenic effects (6766). Theoretically, it might interfere with estrogens taken concomitantly.

ANTIDIABETES DRUGS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = B

Theoretically, stinging nettle might have additive effects with antidiabetes drugs.

Details

Clinical research shows that stinging nettle might decrease blood glucose levels in patients with diabetes (91519,102865).

DIURETIC DRUGS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = D

Theoretically, combining stinging nettle with diuretic drugs may have additive effects.

Details

Animal research suggests that the above ground parts and roots of stinging nettle may have a diuretic effect (1,4,11,76402).

LITHIUM

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = D

Theoretically, stinging nettle might reduce excretion and increase levels of lithium.

Details

Animal research suggests that stinging nettle has diuretic and natriuretic properties, which could alter the excretion of lithium (76402). The dose of lithium might need to be decreased.

WARFARIN (Coumadin)

Interaction Rating = Moderate Be cautious with this combination.

Severity = High • Occurrence = Possible • Level of Evidence = D

There is some concern that stinging nettle might decrease the effects of anticoagulant drugs such as warfarin.

Details

Stinging nettle contains a significant amount of vitamin K (19). When taken in large quantities, this might interfere with the activity of warfarin.

YOHIMBE

ANTICOAGULANT/ANTIPLATELET DRUGS

Interaction Rating = Minor Be watchful with this combination.

Severity = Mild • Occurrence = Possible • Level of Evidence = D

Theoretically, combining yohimbe bark with antiplatelet or anticoagulant drugs might have additive effects; however, this has not been reported in clinical research.

Details

Research in healthy adults shows that taking yohimbine, a constituent of yohimbe bark, in doses of 8 mg or more, seems to inhibit platelet aggregation in vitro by binding to the alpha-2 adrenoceptor (86773,86806,86835,86853). The effects of yohimbe bark itself are unclear; yohimbe bark contains 0.6% to 1.38% yohimbine, but it is unclear how much is absorbed (86862,89263).

ANTIHYPERTENSIVE DRUGS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = D

Theoretically, yohimbe might reduce the effects of antihypertensive drugs.

Details

Yohimbine, a constituent of yohimbe, is an alpha-2 adrenoceptor antagonist and has been reported to increase blood pressure in clinical research. Theoretically, concomitant use of yohimbe and antihypertensive drugs can interfere with blood pressure control (11,17465).

CLONIDINE (Catapres)

Interaction Rating = Moderate Be cautious with this combination.

Severity = High • Occurrence = Possible • Level of Evidence = D

Theoretically, yohimbe might precipitate clonidine withdrawal.

Details

Chronic clonidine use can downregulate alpha-2 adrenoreceptors. Animal research and one human case report suggest that concomitant administration of yohimbine, an alpha-2 adrenoceptor antagonist, may precipitate clonidine withdrawal and lead to sympathomimetic toxicity, including hypertensive crisis (111406).

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES

Interaction Rating = Minor Be watchful with this combination.

Severity = Mild • Occurrence = Possible • Level of Evidence = D

Theoretically, yohimbe might decrease the levels and clinical effects of CYP1A2 substrates.

Details

In vitro research shows that yohimbe extract induces CYP1A2 enzymes (111404).

CYTOCHROME P450 2D6 (CYP2D6) INHIBITORS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = B

CYP2D6 inhibitors may increase the levels and adverse effects of yohimbine, a constituent of yohimbe.

Details

In vitro and clinical research shows that the yohimbe bark constituent, yohimbine, is metabolized by CYP2D6 isoenzymes (105688,105697,105698). Paroxetine, a cytochrome P450 (CYP) 2D6 inhibitor, increases the maximum serum concentration of yohimbine and reduces the clearance of yohimbine compared to yohimbine alone in patients who are extensive CYP2D6 metabolizers. (114932).

CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = D

Theoretically, yohimbe might increase the levels and adverse effects of CYP2D6 substrates.

Details

In vitro research suggests that yohimbine, a constituent of yohimbe bark, inhibits CYP2D6 enzyme activity (23117).

CYTOCHROME P450 3A4 (CYP3A4) INHIBITORS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Possible • Level of Evidence = D

Theoretically, CYP3A4 inhibitors might increase the levels and adverse effects of yohimbine, a constituent of yohimbe bark.

Details

In vitro and clinical research shows that the yohimbe bark constituent, yohimbine, is metabolized by CYP3A4 enzymes (105688,105698). Theoretically, drugs that inhibit CYP3A4 might increase the levels and adverse effects of yohimbine.

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

Interaction Rating = Minor Be watchful with this combination.

Severity = Mild • Occurrence = Possible • Level of Evidence = D

Theoretically, yohimbe might decrease the levels and clinical effects of CYP3A4 substrates.

Details

In vitro research shows that yohimbe extract induces CYP3A4 enzymes (111404).

MONOAMINE OXIDASE INHIBITORS (MAOIs)

Interaction Rating = Major Do not take this combination.

Severity = High • Occurrence = Likely • Level of Evidence = D

Concomitant use of MAOIs with yohimbe can result in additive effects.

Details

Yohimbine, a constituent of yohimbe, has MAO inhibitory effects. At high doses, yohimbine is a non-selective inhibitor of MAO (11,12).

PAROXETINE (Paxil)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = B

Paroxetine decreases the clearance of yohimbine and may increase its effects.

Details

Paroxetine, a cytochrome P450 (CYP) 2D6 inhibitor, increases the maximum serum concentration of yohimbine by about 350% and reduces the clearance of yohimbine by about 80% compared to yohimbine alone in patients who are extensive CYP2D6 metabolizers. No significant changes in pharmacokinetic parameters of yohimbine were observed with coadministration of paroxetine in patients who are poor CYP2D6 metabolizers (114932).

PHENOTHIAZINES

Interaction Rating = Moderate Be cautious with this combination.

Severity = High • Occurrence = Possible • Level of Evidence = D

Theoretically, using yohimbine with phenothiazines might have additive effects.

Details

Yohimbine, a constituent of yohimbe, has alpha-2 adrenergic antagonist effects. Theoretically, combining it with phenothiazines can cause additive alpha-2 adrenergic antagonism (19).

STIMULANT DRUGS

Interaction Rating = Moderate Be cautious with this combination.

Severity = High • Occurrence = Possible • Level of Evidence = D

Theoretically, taking yohimbe with stimulant drugs can have additive effects.

Details

Yohimbine, a constituent of yohimbe, has sympathomimetic effects and increases blood pressure in a dose-dependent manner. Theoretically, taking yohimbe with stimulant drugs can have additive stimulant and hypertensive effects (11,12,105698).

TRICYCLIC ANTIDEPRESSANTS (TCAs)

Interaction Rating = Moderate Be cautious with this combination.

Severity = High • Occurrence = Possible • Level of Evidence = D

Theoretically, taking yohimbe with TCAs can increase adverse effects.

Details

A small clinical study in patients taking TCAs for at least 4 weeks shows that receiving doses of intravenous yohimbine 2.5-20 mg daily for up to 7 days precipitates severe anxiety, agitation, and tremor (105881). The effects of yohimbe bark itself are unclear; oral yohimbe bark contains 0.6% to 1.38% yohimbine, but it is unclear how much is absorbed (86862,89263).

ZINC

AMILORIDE (Midamor)

Interaction Rating = Minor Be watchful with this combination.

Severity = Insignificant • Occurrence = Probable • Level of Evidence = B

Amiloride can modestly reduce zinc excretion and increase zinc levels.

Details

Clinical research shows that amiloride can reduce urinary zinc excretion, especially at doses of 10 mg per day or more. This zinc-sparing effect can help to counteract zinc losses caused by thiazide diuretics, but it is unlikely to cause zinc toxicity at usual amiloride doses (830,11626,11627,11634). The other potassium-sparing diuretics, spironolactone (Aldactone) and triamterene (Dyrenium), do not seem to have a zinc-sparing effect.

ATAZANAVIR (Reyataz)

Interaction Rating = Minor Be watchful with this combination.

Severity = Insignificant • Occurrence = Probable • Level of Evidence = B

Zinc modestly reduces levels of atazanavir, although this effect does not seem to be clinically significant.

Details

Clinical research shows that zinc might decrease serum atazanavir levels by chelating with atazanavir in the gut and preventing its absorption (93578). Although a single dose of zinc sulfate (Solvazinc tablets) 125 mg orally does not affect atazanavir concentrations in patients being treated with atazanavir/ritonavir, co-administration of zinc sulfate 125 mg daily for 2 weeks reduces plasma levels of atazanavir by about 22% in these patients. However, despite this decrease, atazanavir levels still remain at high enough concentrations for the prevention of HIV virus replication (90216).

CEPHALEXIN (Keflex)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = B

Zinc might decrease cephalexin levels by chelating with cephalexin in the gut and preventing its absorption.

Details

A pharmacokinetic study shows that zinc sulfate 250 mg taken concomitantly with cephalexin 500 mg decreases peak levels of cephalexin by 31% and reduces the exposure to cephalexin by 27%. Also, taking zinc sulfate 3 hours before cephalexin decreases peak levels of cephalexin by 11% and reduces the exposure to cephalexin by 18%. By decreasing cephalexin levels, zinc might increase the risk of treatment failure. This effect does not occur when zinc is taken 3 hours after the cephalexin dose (94163). To avoid an interaction, advise patients take zinc sulfate 3 hours after taking cephalexin.

CISPLATIN (Platinol-AQ)

Interaction Rating = Moderate Be cautious with this combination.

Severity = High • Occurrence = Possible • Level of Evidence = D

Theoretically, zinc might interfere with the therapeutic effects of cisplatin.

Details

Animal research suggests that zinc stimulates tumor cell production of the protein metallothionein, which binds and inactivates cisplatin (11624,11625). It is not known whether zinc supplements or high dietary zinc intake can cause clinically significant interference with cisplatin therapy. Cisplatin might also increase zinc excretion.

INTEGRASE INHIBITORS

Interaction Rating = Moderate Be cautious with this combination.

Severity = High • Occurrence = Possible • Level of Evidence = D

Theoretically, taking zinc along with integrase inhibitors might decrease the levels and clinical effects of these drugs.

Details

Zinc is a divalent cation. Pharmacokinetic studies have shown that other divalent cations such as calcium and iron can decrease blood levels of the integrase inhibitor dolutegravir through chelation (93578,93579).

PENICILLAMINE (Cuprimine, Depen)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = B

Zinc might reduce the levels and clinical effects of penicillamine.

Details

By forming an insoluble complex with penicillamine, zinc interferes with penicillamine absorption and activity. Zinc supplements reduce the efficacy of low-dose penicillamine (0.5-1 gram/day), but do not seem to affect higher doses (1-2.75 gram/day), provided dosing times are separated (2678,4534,11605). Advise patients to take zinc and penicillamine at least 2 hours apart.

QUINOLONE ANTIBIOTICS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = B

Zinc can decrease the levels and clinical effects of quinolones antibiotics.

Details

Quinolones form complexes with zinc in the gastrointestinal tract, reducing absorption of both the quinolone and zinc if taken at the same time (828,2682,3046,11600). Advise patients to take these drugs at least 2 hours before, or 4-6 hours after, zinc supplements.

RITONAVIR (Norvir)

Interaction Rating = Moderate Be cautious with this combination.

Severity = Mild • Occurrence = Probable • Level of Evidence = B

Zinc modestly reduces levels of ritonavir.

Details

Clinical research shows that zinc might reduce serum ritonavir levels by chelating with ritonavir in the gut and preventing its absorption (93578). In patients with HIV, ritonavir is taken with atazanavir to prevent the metabolism and increase the effects of atazanavir. A pharmacokinetic study shows that, in patients being treated with atazanavir/ritonavir, co-administration of zinc sulfate (Solvazinc tablets) 125 mg as a single dose or as multiple daily doses for 2 weeks reduces plasma levels of ritonavir by about 16% (90216). However, atazanavir levels still remains high enough to prevent HIV virus replication. Therefore, the decrease in ritonavir levels is not likely to be clinically significant.

TETRACYCLINE ANTIBIOTICS

Interaction Rating = Moderate Be cautious with this combination.

Severity = Moderate • Occurrence = Probable • Level of Evidence = B

Zinc might reduce levels of tetracycline antibiotics.

Details

Tetracyclines form complexes with zinc in the gastrointestinal tract, which can reduce absorption of both the tetracycline and zinc when taken at the same time (3046,4945). Taking zinc sulfate 200 mg with tetracycline reduces absorption of the antibiotic by 30% to 40% (11615). Demeclocycline and minocycline cause a similar interaction (4945). However, doxycycline does not seem to interact significantly with zinc (11615). Advise patients to take tetracyclines at least 2 hours before, or 4-6 hours after, zinc supplements to avoid any interactions.

Report an Adverse Reaction to Supreme DHEA for Intimacy

Adverse Effects view details

Below is general information about the adverse effects of the known ingredients contained in the product Supreme DHEA for Intimacy. Some ingredients may not be listed. This information does NOT represent a recommendation for or a test of this specific product as a whole.

DAMIANA

General ...Orally, adverse effects to damiana seem to be rare; however, a thorough safety evaluation has not been conducted.

Neurologic/CNS ...Orally, 200 grams of damiana extract has caused tetanus-like convulsions and paroxysms resulting in symptoms similar to rabies or strychnine poisoning (4).

General ...Orally and topically, DHEA seems to be well tolerated when used in typical doses, short-term. However, there is some concern that long-term oral use of DHEA may be linked to a greater risk for cancer.
Most Common Adverse Effects:
Orally: Acne, headache, insomnia, mood changes, and nausea. In females, masculinization symptoms including deepening of the voice, increased size of genitals, irregular menses, oily skin, reduced breast size, and unnatural hair growth. In males, aggression, breast tenderness or enlargement (gynecomastia), urinary urgency, and testicular wasting.
Serious Adverse Effects (Rare):
Orally: Possible increased risk for cardiovascular events and various types of cancer.

Cardiovascular ...Incidences of arrhythmia (21334,47540), chest pain (21332,21333), palpitations (21332,21333,88492), hypertension, and transient ischemic attacks (21353,21354,47300) have been reported. DHEA has also been found to decrease high-density lipoprotein (HDL) levels (21344,21345,21346,21347,21348,21349) and increase triglycerides (21334).

Dermatologic ...Acne has been the most commonly reported adverse effect in human research, particularly in females (2113,2114,4242,7614,7559,12561,12574,21346,21351,21354)(21355,21356,21357,21358,21360,21361,21362,21363,21364,47300)(47355,47409,90304,103185). However, it is generally mild and may be treated by reducing the dose (7559). Incidences of contact dermatitis (47402), acneiform dermatitis (2113), greasy hair and skin (17218,21351,21355,21363,21387,21389,47355), keratosis (47402), skin rash (12574,21361,21363), erythema (21334), scalp itching (17218,21357), and skin spots (21387) have also been reported. Increased hair growth and hirsutism have been noted in several clinical trials, including the development of mild mustache in females (2114,4242,12561,12574,17218,21346,21351,21354,21355,21358) (21361,21362,21363,21370,21387,21389,21415,47300). Increased perspiration and odor have also been reported in human research (17218,21354,21356,21357).

Endocrine ...In postmenopausal patients, high doses of DHEA (1600 mg daily) induced insulin resistance, reportedly due to increased androgen levels that occurred during supplementation (21324).

Gastrointestinal ...Gastrointestinal disturbances such as nausea, diarrhea, and abdominal discomfort have been noted in human research (2111,6098,7559,12574,21348,21358,21386).

Genitourinary ...In older adults, elevated and severe urinary symptoms (as evidenced by scores of more than 20, using the American Urological Association Symptom Index for Benign Prostatic Hyperplasia [International Prostate Symptom Score]) and urinary tract infection were reported (21353). Rare incidences of abnormal menses (2114) and increased discharge (21415) have been reported. DHEA has been associated with hematuria (47300).

Hepatic ...Elevated liver enzymes have been reported following DHEA supplementation (21364,47300). However, an analysis of multiple studies in varied patient populations taking DHEA supplements found no elevations in liver enzymes (107791).

Musculoskeletal ...Incidences of asthenia, arthralgia, and myalgia, including calf cramps, have been reported (12574,21354,21358,21365,47355).

Neurologic/CNS ...In humans, dizziness, fatigue, malaise, sleep disturbances, increased dreaming, night sweats, restlessness, "painful spots," and a crawling scalp sensation have been reported (3865,21354,21363,21389). There is a case of seizure associated with DHEA use in a 30 year-old female with fragile X syndrome and no history of convulsive disorder who used DHEA to try to improve ovarian production (47344).

Ocular/Otic ...In patients with Sjögren syndrome, maculae lesions, ocular pain and dryness, and painful eye exams have been reported (21358,21363,21365).

Oncologic ...Preclinical research suggests that DHEA may increase the risk of cancer, particularly prostate, liver, breast, and pancreatic cancers (2111,10370,10401,10403,12565,21332,21333,21334,47251,47256)(47366,47388,47539). High concentrations of DHEA in postmenopausal patients have been associated with an increased risk of breast cancer (2115,6445).

Psychiatric ...DHEA-induced mania has been reported (5870,6102,7023,21383). Clinical studies have also reported anxiety, nervousness, irritability, emotional change, and depression in patients receiving DHEA (2114,21358,21360,21370).

Pulmonary/Respiratory ...Increased cough and nasal congestion have been noted in human research (3865,11334). A report of acute respiratory failure was made in clinical study evaluating the use of DHEA in patients with myotonic dystrophy (type 1) (21334).

Other ...Perceived increases in weight gain have been reported with use of DHEA (2114,21361).

General ...Orally, oats are well tolerated.
Most Common Adverse Effects:
Orally: Abdominal distension, bloating, flatulence, and unpleasant taste.
Topically: Burning, contact dermatitis, itching, and redness.

Dermatologic ...Topically, oat-containing preparations can cause contact dermatitis (12515). Redness, burning, and itchiness have also been reported (103340).

Gastrointestinal ...When consumed orally, oats provide fiber. Increasing fiber in the diet can cause flatulence, bloating, abdominal distention, and unpleasant taste. To minimize side effects, doses should be slowly titrated to the desired level. These adverse effects usually subside with continued use (12514).
In patients who have difficulty chewing food, or those with conditions that decrease small bowel motility, oat bran may cause bezoars (concretions) and intestinal obstruction. Oats and oat bran are unlikely to cause obstruction without other causative factors (4979,4985).

Immunologic ...In a case report, a 45-year-old male developed acute generalized urticaria, facial angioedema, and dyspnea immediately after consuming oat flour. The reaction resolved after emergency care for anaphylaxis. Further investigation revealed an IgE-mediated hypersensitivity reaction to oat proteins (113490).

SARSAPARILLA

General ...Orally, sarsaparilla seems to be well tolerated.

Gastrointestinal ...Orally, there is some concern that sarsaparilla may cause GI irritation when used in large amounts (11,18). However, these claims cannot be substantiated.

Pulmonary/Respiratory ...Occupational exposure to sarsaparilla root dust can cause rhinitis and asthma symptoms (4111).

Renal ...Orally, there is some concern that sarsaparilla may cause temporary kidney impairment and diuresis, possibly leading to shock, when used in large amounts (11,18). However, these claims cannot be substantiated.

SAW PALMETTO

General ...Orally, saw palmetto is well tolerated and adverse effects are mild, infrequent, and reversible.
Most Common Adverse Effects:
Orally: Abdominal pain, constipation, decreased libido, diarrhea, dizziness, fatigue, headache, nausea, rhinitis, vomiting.

Cardiovascular ...Occasionally, cases of hypertension, postural hypotension, tachycardia, angina pectoris, arrhythmia, extrasystole, angiopathy, myocardial infarction, and congestive heart failure have been reported in patients using saw palmetto orally (6424,6484,6752,6772,17684,73388,89441). One case of severe bradycardia and second degree heart block was reported in a 64 year-old male taking an unknown amount of saw palmetto for a few weeks (96413).

Dermatologic ...A case report describes a 61-year-old male who developed a fixed drug eruption with localized blisters and erosions three days after starting oral saw palmetto. The lesions resolved when saw palmetto was stopped, but recurred when it was reintroduced six months later. Topical corticosteroid treatment was necessary and the patient was left with some residual hyperpigmented patches (104805). A combination of saw palmetto and beta-sitosterol has been associated with a single report of worsening acne (15550).

Endocrine ...Two case reports involving one 11-year-old female undergoing treatment for telogen effluvium and another 10-year-old female undergoing treatment for hirsutism, describe hot flashes and the onset of menarche associated with use of saw palmetto. One of these patients was consuming saw palmetto in a food supplement; the other was taking a supplement containing saw palmetto 320 mg daily (73361,96414). In both cases, the hot flashes resolved following treatment discontinuation. In one case, a rechallenge with saw palmetto caused a recurrence of hot flashes.

Gastrointestinal ...Gastrointestinal complaints such as nausea, vomiting, constipation, diarrhea, gastralgia, and halitosis are the most frequently reported adverse effects associated with saw palmetto (6484,6752,60442,73315,73320,73348,73354,73383,73385,73388,89441). Less often, cases of duodenal ulcer, dyspepsia, or heartburn have been reported (6772,73329,73354). Meteorism (intestinal gas accumulation) has also been reported with saw palmetto, although causality was unclear (60442).

Genitourinary ...Some clinicians are concerned that saw palmetto might cause erectile dysfunction, ejaculatory disturbance, or altered libido because of its potential effects on 5-alpha-reductase. Some preliminary clinical studies have reported sexual dysfunction, particularly ejaculatory dysfunction, erectile dysfunction, and reduced libido, in patients taking saw palmetto (5093,17202,17684,73383,89441). However, most of these patients were previously diagnosed with prostate disorders, so causality is unclear. Additionally, several clinical studies indicate that the occurrence of impotence in males taking saw palmetto is similar to placebo and tamsulosin (Flomax), and significantly less than finasteride (Proscar) (2732,6424,17306,107481). Rarely, cases of testicular pain, vesical tenesmus, and urinary tract infections have been reported in patients using saw palmetto extract orally (73388).

Hematologic ...Saw palmetto might have antiplatelet effects and potentially increase the risk of bleeding in some patients. There is one report of excessive intraoperative bleeding in a patient who took saw palmetto prior to surgery. Bleeding time normalized when saw palmetto was discontinued (8659). Also, one case of cerebral hemorrhage has been reported, but details are not available to determine causality (6772,73348). A case of retroperitoneal hematoma after bilateral inguinal hernia repair is reported in a male patient taking saw palmetto. The patient was discharged after a 3-day hospitalization in stable condition (112177).

Hepatic ...A case report describes a patient who developed acute hepatitis and pancreatitis while taking saw palmetto. Symptoms resolved when saw palmetto was discontinued, and reemerged upon re-challenge (14457). Other cases of acute hepatitis and pancreatitis, with elevated alkaline phosphatase, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and bilirubin have been reported in patients using saw palmetto orally (14457,73350,73351).

Musculoskeletal ...Orally, saw palmetto may cause fatigue, weakness, muscle pain, and back pain, although these adverse events are rare (6424,73388,89441). A case of saw palmetto-related rhabdomyolysis was reported in an 82-year-old male presenting with kidney dysfunction, increased C-reactive protein levels, and elevated serum creatine kinase (73358).

Neurologic/CNS ...Orally, saw palmetto can cause headaches, dizziness, insomnia, and fatigue (6750,6752,6772,11354,60442,73348,73385,73388,89441).

Ocular/Otic ...A case of intraoperative floppy-iris syndrome (IFIS) has been reported in a patient using saw palmetto orally (73340). However, no statistically significant association between saw palmetto and IFIS was found in a case series of 660 patients undergoing cataract surgery (73347).

Pulmonary/Respiratory ...Rhinitis is one of the more commonly reported adverse effects of saw palmetto (73348). One patient taking saw palmetto extract 160 mg twice daily reported "breathlessness" (73388). Two cases of respiratory depression have been reported in patients using saw palmetto extract (Permixon) 320 mg (6772).

General ...Orally, stinging nettle seems to be generally well tolerated.
Most Common Adverse Effects:
Orally: Constipation, diarrhea.
Topically: Contact with the raw plant causes itching, rash, and stinging.

Dermatologic ...Topically, fresh stinging nettle leaves and stalk can cause localized rash, itching, and stinging (12490,76399,76412,76414,76417,76428,76448,96746). Usually, short exposure to stinging nettle results in a transient urticarial reaction and a stinging sensation which may persist for more than 12 hours (76399,76414,76417,96746). In one report, a patient placed a fresh stinging nettle leaf on the tongue to suck out the sap of the leaf. Severe tongue edema, pain, and urticaria developed within 5 minutes. Symptoms continued for several hours after the leaf was removed (15197). In another case report, a young couple intoxicated with methamphetamine fell and laid in a stinging nettle bush for 20 minutes, after which urticaria and pain continued for 2-3 weeks, and a heightened sensitivity to cold persisted for several months (96746).

Endocrine ...A case of gynecomastia has been reported for a 33-year-old male who consumed stinging nettle tea 2 cups daily for one month prior to symptom onset. The condition subsided one month after discontinuing stinging nettle tea (76410).
There have been two cases of galactorrhea associated with the consumption of stinging nettle for one month (76410,108902). In one case, a 33-year-old female consuming stinging nettle tea showed high levels of estradiol and low levels of follicle stimulating hormone (FSH) and luteinizing hormone (LH). The levels of these hormones normalized 6 weeks after discontinuing stinging nettle tea (76410). In the other case report describing a 30-year-old female self-treating with stinging nettle 500 mg daily, hormone levels were not reported; however, a mammogram showed scattered areas of fibroglandular density and benign-appearing calcifications. This patient had complete resolution of symptoms 1 week after discontinuation of stinging nettle (108902).

Gastrointestinal ...Orally, stinging nettle root can cause gastrointestinal complaints, including diarrhea and constipation (1,7,11230). Stinging nettle above ground parts may cause mild gastrointestinal discomfort when taken on an empty stomach (7035). Stinging nettle juice may cause diarrhea (1). One patient taking a combination product containing stinging nettle root extract and pygeum bark extract (Prostatonin, Pharmaton) experienced continual gastrointestinal pain and hyperperistalsis. It is not clear if this effect was due to stinging nettle or pygeum (70230).

Genitourinary ...There is a case report of decreased ejaculatory volume associated with an herbal blend product containing stinging nettle root extract, saw palmetto extract, pumpkin seed oil extract, lemon bioflavonoid extract, and beta-carotene (5093). It is unclear if this was due to stinging nettle, other ingredients, or the combination.

Hepatic ...A case of idiosyncratic drug-induced liver disease (DILI) is reported in a 36-year-old female who presented with abdominal pain after 1 month of taking an herbal liver detox tea containing stinging nettle and other ingredients. Remarkable laboratory values included elevated liver enzymes, alkaline phosphatase, and total bilirubin. The patient received a loading dose of N-acetylcysteine and was hospitalized for 12 days (112178). However, it is unclear if the adverse effect was due to the stinging nettle, other ingredients, or the combination.

Other ...Orally, stinging nettle root can cause sweating (1,7).

YOHIMBE

General ...Orally, there is limited information available about the adverse effects of yohimbe. Yohimbine, a constituent of yohimbe, might be unsafe; most reported adverse effects are dose-related.
Most Common Adverse Effects:
Orally: Yohimbine, a constituent of yohimbe, has been associated with anxiety, agitation, diaphoresis, diarrhea, flushing, headache, hypertension, increased urination, nausea, tachycardia, tremors, vertigo, and vomiting.
Serious Adverse Effects (Rare):
Orally: Yohimbine, a constituent of yohimbe, has been associated with atrial fibrillation, hypertensive crisis, myocardial infarction, and QT interval prolongation.

Cardiovascular ...Orally, yohimbine, a constituent of yohimbe, has been associated with hypertension, especially at higher doses (3312,17465,86801,86802,86804,86811,86820,86822,86834,86856)(86786,86896). A case of hypertensive crisis was reported in a 63-year-old male taking a yohimbine-containing herbal product once daily for one month. The patient was successfully managed with intravenous nitroprusside followed by clonidine (91521). Tachycardia, fluid retention, palpitations, and chest discomfort have also been reported (3312,17465,86786,86793,86801,86802,86804,86822,86843,86854)(86856,86866,86867,86869,86871,86874,86875). Conduction abnormalities have also been reported (86856,86786). There have been some reports of myocardial infarction, atrial fibrillation, and QT interval prolongation (17465). In theory, these effects may also occur with the use of yohimbe bark extract.

Dermatologic ...Orally, yohimbine, a constituent of yohimbe, may cause rash, erythrodermic skin eruption, and exanthema (3312,3971,86804,86896,86878).

Gastrointestinal ...Orally, yohimbine, a constituent of yohimbe, may cause nausea, vomiting, increased salivation, diarrhea, and gastrointestinal distress (3970,17465,49902,86780,86781,86786,86801,86804,86824,86827)(86828,86829,86863,86878,86882,86896).

Genitourinary ...Orally, yohimbine may cause dartos contraction or decreased libido in some patients (86786,86882). A case of severe intractable priapism has been reported for a 42-year-old male who took a supplement containing yohimbe extract the previous day for sexual enhancement. Treatment with phenylephrine 400 mcg was unsuccessful at resolving the priapism, so surgical insertion of a proximal cavernosal spongiosum shunt was needed (86804).

Hematologic ...A case of drug-induced agranulocytosis has been reported following prolonged use of oral yohimbine, a constituent of yohimbe (86877).

Immunologic ...There is one report of a hypersensitivity reaction including fever; chills; malaise; itchy, scaly skin; progressive renal failure; and lupus-like syndrome associated with ingestion of a one-day dose of yohimbine, a constituent of yohimbe (6169).

Musculoskeletal ...Orally, yohimbine, a constituent of yohimbe, may cause muscle aches (86850).

Neurologic/CNS ...Orally, yohimbine, a constituent of yohimbe, has been associated with reports of general central nervous system (CNS) and autonomic excitation, tremulousness, head twitching, seizure threshold changes, enhanced brain norepinephrine release, decreased energy, dizziness, vertigo, and headache (3312,3971,86774,86779,86786,86804,86827,86857,86870,86882)(86883). Cold feet and chills have also been reported with yohimbine (86827,86896). Other adverse reactions include flushing and diaphoresis (17465). Excessive doses of yohimbine can also cause paralysis (11,18). A case of acute neurotoxicity characterized by malaise, vomiting, loss of consciousness, and seizures has been reported for a 37-year-old bodybuilder who ingested a single dose of yohimbine 5 grams. Improvement was seen within 12 hours following treatment with furosemide, labetalol, clonidine, urapidil, and gastrointestinal decontamination (86801).

Psychiatric ...Orally, yohimbine, a constituent of yohimbe, may increase malaise, fatigue, insomnia, restlessness, agitation, and anxiety (3312,3970,3971,17465,86786,86801,86804,86822,86827,86834)(86868,86878,86882,86896). In a clinical study of healthy subjects, administration of yohimbine increased impulsivity, with larger doses increasing impulsivity more than 50% (86784,86810).

Pulmonary/Respiratory ...Orally, yohimbine, a constituent of yohimbe, may cause bronchospasm, tachypnea, cough, and rhinorrhea (17465,86825,86850). A case of sinusitis characterized by pain and discomfort above both eyes has been reported for a 59-year-old male taking yohimbine 5.4 mg three times daily to treat erectile dysfunction. Symptoms resolved within 24 hours of discontinuing yohimbine. The effect was attributed to the alpha-2 adrenergic antagonist effects of yohimbine (94112). Excessive doses of yohimbine can cause respiratory depression (1118).

Renal ...Orally, yohimbine, a constituent of yohimbe, may increase urinary frequency (3312,3970,3971,17465,86804,86827,86850,86861,86882). A case of acute renal failure has been reported for a 42-year-old male taking yohimbine. Normalization of renal function was achieved following 2 weeks of treatment with corticosteroids. The renal dysfunction was attributed to yohimbine-induced systemic lupus erythematosus (6169).

ZINC

General ...Orally, zinc is well tolerated in doses below the tolerable upper intake level (UL), which is 40 mg daily for adults. Topically, zinc is well tolerated.
Most Common Adverse Effects:
Orally: Abdominal cramps, diarrhea, metallic taste, nausea and vomiting (dose-related).
Topically: Burning, discoloration, itching, stinging, and tingling when applied to irritated tissue.
Intranasally: Bad taste, dry mouth, headache, irritation, reduced sense of smell.
Serious Adverse Effects (Rare):
Orally: There have been cases of acute renal tubular necrosis, interstitial nephritis, neurological complications, severe vomiting, and sideroblastic anemia after zinc overdose.
Intranasally: There have been cases where intranasal zinc caused permanent loss of smell (anosmia).

Dermatologic ...Topically, zinc can cause burning, stinging, itching, and tingling when applied to inflamed tissue (6911,8623,87297). Zinc oxide can be deposited in the submucosal tissue and cause dark discoloration of the skin. This can occur with prolonged topical application to intact skin, application to eroded or ulcerated skin, or penetrating traumatic exposure, and also parenteral administration (8618).
In rare cases, oral zinc has resulted in worsened acne (104056), skin sensitivity (6592), a leishmanial reaction with a macular rash that occurred on exposed parts of the body (86935), eczema (104055), systemic contact dermatitis (109457), and the development of severe seborrheic dermatitis (86946).

Gastrointestinal ...Orally, zinc can cause nausea (338,2663,2681,6592,6700,18216,106230,106233,106227,113661), vomiting (2663,2681,6519,6592,96069,96074), a metallic or objectionable taste in the mouth (336,338,6700,11350,18216,106902,113661), abdominal cramping (6592,96069), indigestion (87227), heartburn (96069), dry mouth (87533), and mouth irritation (336,2619). When used orally in amounts above the tolerable upper intake level, zinc may cause irritation and corrosion of the gastrointestinal tract (331,86982,87315,106902), watery diarrhea (1352), epigastric pain (2663,2681), and severe vomiting (2663,2681).
Intranasally, zinc can cause bad taste, dry mouth, and burning and irritation of the throat (8628,8629).
When used topically as a mouth rinse, zinc may cause tooth staining (90206).

Hematologic ...There is concern that high daily doses of zinc, above the tolerable upper intake level (UL) of 40 mg per day, might increase the risk of copper deficiency, potentially leading to anemia and leukopenia (7135,112473). To prevent copper deficiency, some clinicians give a small dose of copper when zinc is used in high doses, long-term (7303).

Hepatic ...There are two cases of liver deterioration in patients with Wilson disease following initiation of treatment with zinc 50-200 mg three times daily. The mechanism of action is not understood, and the event is extremely uncommon (86927,87470).

Immunologic ...Daily doses of 300 mg of supplemental zinc for 6 weeks appear to impair immune response (7135). A case of erythematosus-like syndrome, including symptoms such as fever, leg ulcers, and rash, has been reported following intake of effervescent tablets (Solvezink) containing zinc 45 mg (87506). In another case, severe neutropenia was reported after taking supplemental zinc 900 mg daily for an unknown duration (112473).

Musculoskeletal ...Orally, zinc may cause body aches in children (113661).

Neurologic/CNS ...Zinc-containing denture adhesives can cause toxicity if used more frequently than recommended for several years. Case reports describe hyperzincemia, low copper levels, blood dyscrasias, and neurological problems, including sensory disturbances, numbness, tingling, limb weakness, and difficulty walking in patients applying denture adhesive multiple times daily for several years (17092,17093,90205,90233). Due to reports of zinc toxicity associated with use of excessive amounts of zinc-containing denture adhesives for several years, GlaxoSmithKline has reformulated Polygrip products to remove their zinc content (17092,17093).
Intranasally (8628) and orally (87534), zinc can cause headache. When used orally in amounts above the tolerable upper intake level (UL), zinc may cause central nervous system (CNS) symptoms including lethargy, fatigue, neuropathy, dizziness, and paresthesia (2663,2681,87369,87470,87533,87534,112473).

Oncologic ...There is concern that zinc might worsen prostate disease. For example, some preliminary evidence suggests that higher dietary zinc intake increases the risk for benign prostatic hyperplasia (6908). Epidemiological evidence suggests that taking more than 100 mg of supplemental zinc daily or taking supplemental zinc for 10 or more years doubles the risk of developing prostate cancer (10306). Another large-scale population study also suggests that men who take a multivitamin more than 7 times per week and who also take a separate zinc supplement have a significantly increased risk of prostate cancer-related mortality (15607). However, a large analysis of population research suggests that there is no association between zinc intake and the risk of prostate cancer (96075).

Pulmonary/Respiratory ...There are several hundred reports of complete loss of sense of smell (anosmia) that may be permanent with use of zinc gluconate nasal gel, such as Zicam (11306,11155,11707,16800,16801,17083,86999,87535). Loss of sense of smell is thought to be dose related but has also been reported following a single application (11306,11155,11707,16800). Patients often report having sniffed deeply when applying the gel, then experiencing an immediate burning sensation, and noticing anosmia within 48 hours (17083). On June 16, 2009, the US Food and Drug Administration (FDA) advised patients not to use a specific line of commercial zinc nasal products (Zicam) after receiving 130 reports of loss of smell (16800). The manufacturer of these products had also received several hundred reports of loss of smell related to its intranasal zinc products (16801). Zinc sulfate nasal spray was used unsuccessfully for polio prophylaxis before the polio vaccine was developed. It caused loss of smell and/or taste, which was sometimes permanent (11713). Animal studies suggest that zinc sulfate negatively affects smell, possibly by damaging the olfactory epithelium and neurons (11156,11703,11704,11705,11706). Zinc gluconate nasal spray has not been tested for safety in animals or humans. The clinical studies of intranasal zinc have not described anosmia as an adverse effect, but testing was not done to see if zinc use adversely affected sense of smell (6471,8628,8629,10247). Also, these clinical studies reported tingling or burning sensation in the nostril, dry nose, nose pain, and nosebleeds.
When used in amounts above the tolerable upper intake level (UL), zinc may cause flu-like symptoms including coughing (2663).

Renal ...In overdose, zinc can cause acute renal tubular necrosis and interstitial nephritis (331,1352,87338).

Other ...Occupational inhalation of zinc oxide fumes can cause metal fume fever with symptoms including fatigue, chills, fever, myalgias, cough, dyspnea, leukocytosis, thirst, metallic taste, and salivation (331).

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