Selenium
Selenium is an essential antioxidant mineral. Supplementation helps most when intake is inadequate, and excess can be harmful.
Overview
What is selenium?
Selenium is an essential mineral and antioxidant. Excessive intake of selenium is harmful and may result in selenium toxicity or death.
Dosage
A typical dose found in supplements containing selenium is 50 to 200 mcg per day.
The recommended dietary allowances (RDA) for selenium are 55 mcg for adults aged 19 years or older, 60 mcg for pregnant women and 70 mcg for lactating women.
Effect graph
Effect heatmap
SupplementDEX Database
59 conditions for , and rated at least stars. All purchase bands. No minimum star filter.
Database Snapshot
Most selenium research is concentrated in a handful of conditions.
- Autoimmune thyroiditis accounts for 12 of 135 studies (9%).
- Hypothyroidism accounts for 9 of 135 studies (7%).
- Cancer accounts for 8 of 135 studies (6%).
- Sparse coverage remains for Acne, Age-related cognitive decline, Alzheimer's disease.
Dietary Sources
Top dietary sources
Food sources
Top dietary sources of selenium include:
Sources include Beef (Skirt Steak), Brazil Nuts, Chicken, Oysters, Pork, Shiitake Mushrooms, Shrimp, Tofu, Tuna, and Whole Wheat Pasta.
Safety
Dose windows
Long-term
The tolerable upper intake level of selenium is 400 mcg per day. Long-term consumption of selenium exceeding 55 mcg per day is associated with development of type 2 diabetes and higher selenium levels in the serum are associated with increased mortality.
Frequently Asked Questions
References
Sources125 references
SupplementDEX uses only high-quality sources to determine supplement effectiveness.
SupplementDEX Database · Autoimmune thyroiditis
12 references1.SupplementDEX Database: Autoimmune thyroiditis — Clinical efficacy of selenium supplementation in patients with Hashimoto thyroiditis: A systematic review and meta-analysis2023
A meta-analysis of 7 Hashimoto trials (342 patients) found selenium 200 mcg/day for 6 months significantly lowered TPOAb and TgAb, with inconsistent effects at 3 months.
2.SupplementDEX Database: Autoimmune thyroiditis — Selenium Supplementation May Decrease Thyroid Peroxidase Antibody Titer via Reducing Oxidative Stress in Euthyroid Patients with Autoimmune Thyroiditis2020
In 40 euthyroid autoimmune thyroiditis patients, 200 mcg/day selenium for 3 months lowered TPOAb and oxidative stress markers versus placebo.
3.SupplementDEX Database: Autoimmune thyroiditis — Selenium Supplementation Significantly Reduces Thyroid Autoantibody Levels in Patients with Chronic Autoimmune Thyroiditis: A Systematic Review and Meta-Analysis2016
A meta-analysis of 16 autoimmune thyroiditis trials found selenium supplementation significantly reduced TPOAb, especially at 3 and 6 months in levothyroxine-treated patients.
4.SupplementDEX Database: Autoimmune thyroiditis — Effects of selenium supplementation in the early stage of autoimmune thyroiditis in childhood: an open-label pilot study2012
In 23 euthyroid children with Hashimoto thyroiditis, 50 mcg/day selenium for 3 months did not change TPOAb or TgAb but was associated with thyroid volume regression in 35%.
5.SupplementDEX Database: Autoimmune thyroiditis — Selenium supplementation in the treatment of Hashimoto's thyroiditis: a systematic review and a meta-analysis2010
A meta-analysis in Hashimoto patients on levothyroxine found selenium 200 mcg/day for 3 months significantly lowered TPOAb and improved mood versus placebo.
6.SupplementDEX Database: Autoimmune thyroiditis — Selenium supplementation does not decrease thyroid peroxidase antibody concentration in children and adolescents with autoimmune thyroiditis2010
In 49 children with autoimmune thyroiditis on levothyroxine for 12 months, selenium 100–200 mcg/day did not reduce TPOAb versus levothyroxine alone.
7.SupplementDEX Database: Autoimmune thyroiditis — [The effect of selenium therapy on autoimmune thyroiditis]2008
In 132 autoimmune thyroiditis patients over 1 year, L-selenomethionine 200 mcg/day reduced antithyroid peroxidase antibodies versus placebo alongside levothyroxine.
8.SupplementDEX Database: Autoimmune thyroiditis — Effects of 12 months treatment with L-selenomethionine on serum anti-TPO Levels in Patients with Hashimoto's thyroiditis2007
In 80 women with Hashimoto thyroiditis, 200 mcg/day selenium for 6 months reduced anti-TPO by 21%; stopping selenium led to antibody rebound.
9.SupplementDEX Database: Autoimmune thyroiditis — Selenium treatment in autoimmune thyroiditis: 9-month follow-up with variable doses2006
In 88 women with autoimmune thyroiditis over 9 months, L-selenomethionine 200 mcg/day suppressed TPOAb, with doses above 100 mcg/day needed for sustained effect.
10.SupplementDEX Database: Autoimmune thyroiditis — Effects of a six month treatment with selenomethionine in patients with autoimmune thyroiditis2003
In 65 autoimmune thyroiditis patients over 6 months, selenomethionine 200 mcg/day plus levothyroxine lowered TPOAb versus levothyroxine plus placebo.
11.SupplementDEX Database: Autoimmune thyroiditis — Selenium in the treatment of autoimmune thyroiditis2003
In 47 autoimmune thyroiditis patients followed 6 months, continuing sodium selenite 200 mcg/day further lowered TPOAb, while stopping selenium raised antibody levels.
12.SupplementDEX Database: Autoimmune thyroiditis — Selenium supplementation in patients with autoimmune thyroiditis decreases thyroid peroxidase antibodies concentrations2002
In 70 women with autoimmune thyroiditis over 3 months, sodium selenite 200 mcg/day reduced TPOAb and improved thyroid ultrasound patterns versus placebo with levothyroxine.
13.SupplementDEX Database: Chronic kidney disease — Effect of selenium supplementation on hemodialysis patients: a meta-analysis2025
A meta-analysis of 7 hemodialysis RCTs (2080 patients) found selenium supplementation did not significantly improve BMI, lipids, or C-reactive protein.
SupplementDEX Database · Kashin-Beck disease
2 references14.SupplementDEX Database: Kashin-Beck disease — Salt-Rich Selenium for Prevention and Control Children with Kashin-Beck Disease: a Meta-analysis of Community-Based Trial2016
A meta-analysis of 11 community trials in China found salt selenium fortification reduced Kashin-Beck disease incidence (OR 0.16) and improved clinical and radiographic outcomes in affected children.
15.SupplementDEX Database: Kashin-Beck disease — Selenium and iodine supplementation of rural Tibetan children affected by Kashin-Beck osteoarthropathy2003
In 324 Tibetan children with Kashin-Beck disease over 12 months, selenium plus iodine improved growth but did not significantly reduce joint pain or radiographic abnormalities versus iodine alone.
SupplementDEX Database · Male infertility
7 references16.SupplementDEX Database: Male infertility — The Effect of Dietary Supplements on Male Infertility in Terms of Pregnancy, Live Birth, and Sperm Parameters: A Systematic Review and Meta-Analysis2025
A 2024 meta-analysis of 50 male infertility RCTs found selenium and other supplements improved individual sperm parameters but did not increase pregnancy or live birth rates.
17.SupplementDEX Database: Male infertility — Systematic Review and Meta-analysis on Effect of Carnitine, Coenzyme Q10 and Selenium on Pregnancy and Semen Parameters in Couples With Idiopathic Male Infertility2022
A meta-analysis of 20 male infertility RCTs found selenium, carnitine, or coenzyme Q10 improved sperm motility and concentration but not pregnancy rates versus placebo.
18.SupplementDEX Database: Male infertility — The Effect of Antioxidants on Sperm Quality Parameters and Pregnancy Rates for Idiopathic Male Infertility: A Network Meta-Analysis of Randomized Controlled Trials2022
A network meta-analysis of 23 RCTs (1917 patients) found L-carnitine ranked first for sperm motility and morphology and ω-3 fatty acids for concentration, but no antioxidant significantly improved pregnancy rate versus placebo.
19.SupplementDEX Database: Male infertility — The Role and Place of Antioxidants in the Treatment of Male Infertility Caused by Varicocele2022
In 163 men with idiopathic or varicocele-related infertility, 6 months of an antioxidant formula containing 3,450 mg/day L-carnitine plus acetyl-L-carnitine improved sperm count, concentration, and motility, with greatest benefit in grade III varicocele.
20.SupplementDEX Database: Male infertility — The role of Vitamin E - Selenium - Folic Acid Supplementation in Improving Sperm Parameters After Varicocelectomy: A Randomized Clinical Trial2019
In 60 varicocelectomy patients over 6 months, vitamin E-selenium-folic acid supplementation improved sperm count and motility versus control after surgery.
21.SupplementDEX Database: Male infertility — The effect of oral selenium supplementation on human sperm motility1998
In 69 subfertile men over 3 months, oral selenium raised plasma selenium but did not significantly improve sperm motility versus placebo.
22.SupplementDEX Database: Male infertility — Selenium supplementation enhances the element concentration in blood and seminal fluid but does not change the spermatozoal quality characteristics in subfertile men1995
In 33 subfertile men over 12 weeks, selenium 200 mcg/day raised blood and seminal selenium and GSH-Px but did not improve sperm quality characteristics.
23.SupplementDEX Database: Cardiovascular health — Effects of Selenium Administration on Blood Lipids: A Systematic Review and Dose-Response Meta-Analysis of Experimental Human Studies2025
A dose-response meta-analysis of 27 RCTs found selenium ≥200 mcg/day lowered HDL cholesterol, suggesting high-dose selenium may adversely affect lipids.
SupplementDEX Database · Migraine
1 reference24.SupplementDEX Database: Migraine — The effect of selenium supplementation on oxidative stress, clinical symptoms and mental health status in patients with migraine: a study protocol for a double-blinded randomized clinical trial2024
A study protocol for a 12-week double-blind RCT plans to test selenium 200 mcg/day for migraine symptoms and oxidative stress biomarkers in 72 patients.
SupplementDEX Database · Preeclampsia
3 references25.SupplementDEX Database: Preeclampsia — Selenium and Preeclampsia: a Systematic Review and Meta-analysis2016
A meta-analysis found lower blood selenium in preeclampsia patients than controls, but selenium supplementation trials did not clearly prevent preeclampsia.
26.SupplementDEX Database: Preeclampsia — Effect of selenium on markers of risk of pre-eclampsia in UK pregnant women: a randomised, controlled pilot trial2014
In 230 UK pregnant women, selenium 60 mcg/day from weeks 12–14 to delivery did not reduce preeclampsia or oxidative stress markers versus placebo.
27.SupplementDEX Database: Preeclampsia — Selenium supplementation and the incidence of preeclampsia in pregnant Iranian women: a randomized, double-blind, placebo-controlled pilot trial2010
In 60 high-risk Iranian pregnant women, selenium 100 mcg/day for 6 months did not prevent preeclampsia versus placebo.
SupplementDEX Database · Bladder cancer
4 references28.SupplementDEX Database: Bladder cancer — Selenium and Vitamin E for Prevention of Non-Muscle-Invasive Bladder Cancer Recurrence and Progression: A Randomized Clinical Trial2023
In 270 patients with non-muscle-invasive bladder cancer, selenium 200 mcg/day and/or vitamin E did not prevent recurrence versus placebo in this factorial RCT.
29.SupplementDEX Database: Bladder cancer — Selenium Exposure and Cancer Risk: an Updated Meta-analysis and Meta-regression2016
An updated meta-analysis of 69 studies found higher selenium exposure associated with lower overall cancer risk, though selenium supplements did not show clear preventive efficacy.
30.SupplementDEX Database: Bladder cancer — Phase III randomised chemoprevention study with selenium on the recurrence of non-invasive urothelial carcinoma. The SELEnium and BLAdder cancer Trial2016
In 292 Belgian bladder cancer patients over 3 years, selenium yeast 200 mcg/day did not reduce non-invasive urothelial carcinoma recurrence versus placebo.
31.SupplementDEX Database: Bladder cancer — Evaluation of vitamin E and selenium supplementation for the prevention of bladder cancer in SWOG coordinated SELECT2012
A SELECT secondary analysis in 34,887 men found selenium, vitamin E, or both did not reduce bladder cancer incidence over median 7.1 years follow-up.
SupplementDEX Database · Diabetes
3 references32.SupplementDEX Database: Diabetes — Potential Benefits of Selenium Supplementation in Reducing Insulin Resistance in Patients with Cardiometabolic Diseases: A Systematic Review and Meta-Analysis2022
A meta-analysis of 10 cardiometabolic disease RCTs (526 patients) found selenium supplementation reduced insulin and HOMA-IR and raised HDL cholesterol.
33.SupplementDEX Database: Diabetes — Selenium exposure and the risk of type 2 diabetes: a systematic review and meta-analysis2018
A meta-analysis of 50 studies found higher selenium exposure associated with increased type 2 diabetes risk, and 200 mcg/day supplementation trials also showed elevated diabetes risk.
34.SupplementDEX Database: Diabetes — Selenium Supplementation for Prevention of Colorectal Adenomas and Risk of Associated Type 2 Diabetes2016
In 1374 participants from the Sel/Cel trial, selenium 200 mcg/day for up to 33 months did not reduce colorectal adenoma recurrence versus placebo.
SupplementDEX Database · Acne
2 references35.SupplementDEX Database: Acne — A 12-week, Randomized, Double-blind, Placebo-controlled Study of the Safety and Efficacy of a Nutraceutical Supplement for Mild to Moderate Non-cystic Acne in Young Adults2024
In a 12-week trial of 40 adults with mild-to-moderate non-cystic acne, a vitamin-mineral-botanical supplement reduced inflammatory and non-inflammatory lesions versus placebo.
36.Effects of Oral Antioxidants on Lesion Counts Associated with Oxidative Stress and Inflammation in Patients with Papulopustular Acne. See external sourceExternal source
37.SupplementDEX Database: Age-related cognitive decline — A cross-sectional study of blood selenium concentration and cognitive function in elderly Americans: National Health and Nutrition Examination Survey 2011-20142020
In 2068 elderly Americans, lower whole-blood selenium was associated with lower cognitive scores in NHANES 2011–2014 cross-sectional analysis.
38.SupplementDEX Database: Age-related cognitive decline — A Phase IIa Randomized Control Trial of VEL015 (Sodium Selenate) in Mild-Moderate Alzheimer's Disease2016
A 24-week phase IIa RCT in 40 mild-to-moderate Alzheimer's patients found sodium selenate was safe but exploratory cognitive and biomarker endpoints did not clearly establish efficacy.
SupplementDEX Database · All-cause mortality
6 references39.SupplementDEX Database: All-cause mortality — Dietary Supplements and Risk of Cause-Specific Death, Cardiovascular Disease, and Cancer: A Systematic Review and Meta-Analysis of Primary Prevention Trials2017
A meta-analysis of 49 primary-prevention trials found vitamin E reduced cardiovascular mortality, folic acid reduced CVD risk, and most other supplements including selenium showed no clear mortality benefit.
40.SupplementDEX Database: All-cause mortality — Selenium supplementation for the primary prevention of cardiovascular disease2013
A Cochrane review found insufficient evidence that selenium supplementation alone prevents cardiovascular disease in the general population.
41.SupplementDEX Database: All-cause mortality — Cardiovascular mortality and N-terminal-proBNP reduced after combined selenium and coenzyme Q10 supplementation: a 5-year prospective randomized double-blind placebo-controlled trial among elderly Swedish citizens2013
In 443 elderly Swedes over 5 years, combined selenium and coenzyme Q10 for 4 years significantly reduced cardiovascular mortality versus placebo.
42.SupplementDEX Database: All-cause mortality — Mortality in randomized trials of antioxidant supplements for primary and secondary prevention: systematic review and meta-analysis2007
A meta-analysis of 68 antioxidant trials (232,606 participants) found no overall mortality benefit; high-bias trials suggested possible harm with beta-carotene, vitamin A, and vitamin E.
43.SupplementDEX Database: All-cause mortality — The SU.VI.MAX Study: a randomized, placebo-controlled trial of the health effects of antioxidant vitamins and minerals2004
In 13,017 French adults followed 7.5 years, daily antioxidant vitamins plus 100 mcg selenium did not reduce total cancer or ischemic cardiovascular disease versus placebo.
44.SupplementDEX Database: All-cause mortality — Do nutritional supplements lower the risk of stroke or hypertension?1998
In 29,584 adults in Linxian, China, beta-carotene, vitamin E, and selenium supplementation for 5 years modestly reduced total and stroke mortality but did not lower hypertension prevalence.
SupplementDEX Database · Alzheimer's disease
1 reference45.SupplementDEX Database: Alzheimer's disease — Probiotic and selenium co-supplementation, and the effects on clinical, metabolic and genetic status in Alzheimer's disease: A randomized, double-blind, controlled trial2019
In 79 Alzheimer's patients over 12 weeks, probiotic plus selenium 200 mcg/day improved inflammation and metabolic markers more than selenium or placebo alone.
46.SupplementDEX Database: Benign prostatic hyperplasia — Serenoa repens, lycopene and selenium versus tamsulosin for the treatment of LUTS/BPH. An Italian multicenter double-blinded randomized study between single or combination therapy (PROCOMB trial)2014
In 225 men with LUTS/BPH, Serenoa repens plus lycopene and selenium combined with tamsulosin significantly improved IPSS, Qmax, and PVR at 6 and 12 months versus monotherapies.
47.SupplementDEX Database: Benign prostatic hyperplasia — Use of selenium-silymarin mix reduces lower urinary tract symptoms and prostate specific antigen in men2013
An RCT of men with lower urinary tract symptoms found selenium plus silymarin for 6 months improved IPSS, urinary flow, bladder volume, and reduced PSA vs placebo.
SupplementDEX Database · Burns
3 references48.SupplementDEX Database: Burns — Reduction of nosocomial pneumonia after major burns by trace element supplementation: aggregation of two randomised trials2006
Combined analysis of two burn trials in 82 patients found IV trace elements including selenium reduced nosocomial pneumonia and ICU stay versus placebo.
49.SupplementDEX Database: Burns — Trace element supplementation modulates pulmonary infection rates after major burns: a double-blind, placebo-controlled trial1998
In 20 burn patients over 30 days, trace element supplementation including selenium raised leukocyte counts and shortened hospital stay versus placebo.
50.SupplementDEX Database: Burns — Influence of large intakes of trace elements on recovery after major burns1994
In 10 burn patients, high-dose IV copper, selenium, and zinc improved trace element status and leukocyte recovery versus standard intake.
SupplementDEX Database · Cancer
5 references51.SupplementDEX Database: Cancer — Does dietary intake of selenium protect against cancer? A systematic review and meta-analysis of population-based prospective studies2020
A meta-analysis of 37 prospective studies found dietary selenium ≥55 mcg/day associated with modestly lower cancer risk, especially from supplements in men.
52.SupplementDEX Database: Cancer — Selenium for preventing cancer2018
An updated Cochrane review found selenium supplementation did not clearly prevent cancer and evidence from observational and trial data remained inconsistent.
53.SupplementDEX Database: Cancer — Effects of selenium supplements on cancer prevention: meta-analysis of randomized controlled trials2011
A meta-analysis of 9 cancer-prevention RCTs (152,538 participants) found selenium supplementation alone associated with lower overall cancer incidence, especially in low-selenium and high-risk populations.
54.SupplementDEX Database: Cancer — The nutritional prevention of cancer: 400 mcg per day selenium treatment2008
In 424 high-risk patients, 400 mcg/day selenium did not reduce total cancer incidence, unlike the NPC trial's 200 mcg/day dose which lowered lung, colon, and prostate cancer risk.
55.SupplementDEX Database: Cancer — The efficacy and safety of multivitamin and mineral supplement use to prevent cancer and chronic disease in adults: a systematic review for a National Institutes of Health state-of-the-science conference2006
A systematic review for NIH found multivitamin/mineral supplements had fair-to-poor evidence for preventing cancer and chronic disease in generally healthy adults.
SupplementDEX Database · Cataracts
1 reference56.SupplementDEX Database: Cataracts — Age-related cataract in men in the selenium and vitamin e cancer prevention trial eye endpoints study: a randomized clinical trial2015
In 11,267 SELECT participants, 5–6 years of selenium 200 mcg/day or vitamin E did not reduce age-related cataract incidence versus placebo.
SupplementDEX Database · Cervical dysplasia
1 reference57.SupplementDEX Database: Cervical dysplasia — The favourable effects of long-term selenium supplementation on regression of cervical tissues and metabolic profiles of patients with cervical intraepithelial neoplasia: a randomised, double-blind, placebo-controlled trial2015
In 58 women with CIN1 over 6 months, selenium yeast 200 mcg/day increased CIN1 regression (88% vs 56%) and improved insulin sensitivity versus placebo.
58.SupplementDEX Database: Chemotherapy-induced nephrotoxicity — Supplementation with antioxidant micronutrients and chemotherapy-induced toxicity in cancer patients treated with cisplatin-based chemotherapy: a randomised, double-blind, placebo-controlled study2004
In 48 cisplatin-treated cancer patients, antioxidant supplementation with vitamin C, E, and selenium did not reduce nephrotoxicity or ototoxicity overall, though higher antioxidant levels correlated with less hearing loss.
SupplementDEX Database · Cirrhosis
1 reference59.SupplementDEX Database: Cirrhosis — Oral antioxidant supplementation for fatigue associated with primary biliary cirrhosis: results of a multicentre, randomized, placebo-controlled, cross-over trial2003
In 44 primary biliary cirrhosis patients with fatigue, 12-week antioxidant supplementation including selenium did not improve fatigue scores versus placebo in this crossover trial.
SupplementDEX Database · Colorectal adenoma
1 reference60.SupplementDEX Database: Colorectal adenoma — Antioxidant supplement and long-term reduction of recurrent adenomas of the large bowel. A double-blind randomized trial2013
In 330 post-polypectomy patients over median 4 years, an antioxidant mix including 200 mcg selenium reduced adenoma recurrence risk by 39% versus placebo.
61.SupplementDEX Database: Congestive heart failure (CHF) — Still reduced cardiovascular mortality 12 years after supplementation with selenium and coenzyme Q10 for four years: A validation of previous 10-year follow-up results of a prospective randomized double-blind placebo-controlled trial in elderly2018
Twelve-year follow-up of 443 elderly Swedes found 4 years of selenium plus coenzyme Q10 continued to associate with lower cardiovascular mortality (28.1% vs 38.7%).
62.SupplementDEX Database: Congestive heart failure (CHF) — Supplementation with Selenium and Coenzyme Q10 Reduces Cardiovascular Mortality in Elderly with Low Selenium Status. A Secondary Analysis of a Randomised Clinical Trial2016
Secondary analysis of 668 elderly Swedes found selenium plus coenzyme Q10 for 4 years reduced cardiovascular mortality most in those with low baseline selenium.
63.SupplementDEX Database: Congestive heart failure (CHF) — Reduced Cardiovascular Mortality 10 Years after Supplementation with Selenium and Coenzyme Q10 for Four Years: Follow-Up Results of a Prospective Randomized Double-Blind Placebo-Controlled Trial in Elderly Citizens2015
Ten-year follow-up of 443 elderly Swedes confirmed 4 years of selenium plus coenzyme Q10 reduced cardiovascular mortality (HR 0.51) versus placebo.
64.SupplementDEX Database: Coronary artery bypass graft surgery — Effects of Selenium Supplementation on Metabolic Status in Patients Undergoing for Coronary Artery Bypass Grafting (CABG) Surgery: a Randomized, Double-Blind, Placebo-Controlled Trial2019
In 33 CABG patients over 4 weeks, selenium 200 mcg/day improved fasting glucose, insulin, HOMA-IR, and HDL versus placebo.
SupplementDEX Database · Dementia
1 reference65.SupplementDEX Database: Dementia — Association of Antioxidant Supplement Use and Dementia in the Prevention of Alzheimer's Disease by Vitamin E and Selenium Trial (PREADViSE)2017
In 3786 older men from PREADViSE/SELECT, vitamin E or selenium used up to 7 years did not prevent dementia versus placebo.
SupplementDEX Database · Depression
1 reference66.SupplementDEX Database: Depression — The role of selenium in depression: a systematic review and meta-analysis of human observational and interventional studies2022
A meta-analysis of 15 studies found selenium supplementation reduced depressive symptoms, while observational serum selenium differences between depressed and healthy subjects were inconsistent.
67.SupplementDEX Database: Diabetic nephropathy — Effect of Selenium Supplementation on Glycemic Control and Lipid Profiles in Patients with Diabetic Nephropathy2016
In 60 diabetic nephropathy patients over 12 weeks, selenium 200 mcg/day lowered insulin, HOMA-IR, and raised glutathione peroxidase versus placebo.
SupplementDEX Database · Dilated cardiomyopathy
2 references68.SupplementDEX Database: Dilated cardiomyopathy — Selenium supplementation in patients with peripartum cardiomyopathy: a proof-of-concept trial2020
In 100 peripartum cardiomyopathy patients with selenium deficiency, selenium 200 mcg/day for 3 months reduced persistent heart failure symptoms but did not improve LVEF recovery versus control.
69.SupplementDEX Database: Dilated cardiomyopathy — Efficacy of Long-term Selenium Supplementation in the Treatment of Chronic Keshan Disease with Congestive Heart Failure2019
In 302 chronic Keshan disease patients followed 10 years, long-term selenium supplementation associated with lower cardiac death risk (HR 0.39) versus no supplementation.
SupplementDEX Database · Esophageal cancer
2 references70.SupplementDEX Database: Esophageal cancer — Antioxidant supplements for prevention of gastrointestinal cancers: a systematic review and meta-analysis2004
A meta-analysis of 14 gastrointestinal cancer prevention trials found antioxidant supplements including selenium did not reduce GI cancer incidence and beta-carotene increased mortality in high-quality trials.
71.SupplementDEX Database: Esophageal cancer — Effects of vitamin/mineral supplementation on the prevalence of histological dysplasia and early cancer of the esophagus and stomach: results from the General Population Trial in Linxian, China1994
In 391 Linxian adults, beta-carotene, vitamin E, and selenium reduced total and stomach cancer mortality during intervention but did not lower esophageal/gastric dysplasia prevalence at endoscopy.
SupplementDEX Database · Graves' eye disease
1 reference72.SupplementDEX Database: Graves' eye disease — Oral selenium improved the disease activity in patients with mild Graves' orbitopathy2021
In mild Graves orbitopathy patients over 6 months, selenium 200 mcg/day twice daily reduced disease activity versus starch placebo in this Mexican RCT.
SupplementDEX Database · Hair loss
1 reference73.SupplementDEX Database: Hair loss — Efficacy and tolerability of an oral supplement containing amino acids, iron, selenium, and marine hydrolyzed collagen in subjects with hair loss (androgenetic alopecia, AGA or FAGA or telogen effluvium). A prospective, randomized, 3-month, controlled, assessor-blinded study2023
In 83 adults with hair loss on standard drug therapy, adding a collagen/amino acid/iron/selenium supplement for 12 weeks improved global assessment scores versus drugs alone (GAS 1.67 vs 0.66; p<0.001).
SupplementDEX Database · Hepatitis C
1 reference74.SupplementDEX Database: Hepatitis C — The effect of antioxidant supplementation on hepatitis C viral load, transaminases and oxidative status: a randomized trial among chronic hepatitis C virus-infected patients2006
In 23 chronic hepatitis C patients over 6 months, vitamin C, E, and selenium 200 mcg/day raised antioxidant levels but did not lower viral load or ALT versus placebo.
SupplementDEX Database · High blood pressure
1 reference75.SupplementDEX Database: High blood pressure — The effects of selenium supplementation on blood lipids and blood pressure in adults: A systematic review and dose-response meta-analysis of randomized control trials2022
A meta-analysis of selenium RCTs found supplementation slightly lowered total cholesterol but raised systolic blood pressure and LDL in some subgroups without improving triglycerides or HDL overall.
SupplementDEX Database · Hyperthyroidism
2 references76.SupplementDEX Database: Hyperthyroidism — Add-On Effect of Selenium and Vitamin D Combined Supplementation in Early Control of Graves' Disease Hyperthyroidism During Methimazole Treatment2022
In 42 newly diagnosed Graves disease patients, adding selenium and vitamin D to methimazole produced faster FT4 reduction at 45 days versus methimazole alone.
77.SupplementDEX Database: Hyperthyroidism — Double-Blind, Placebo-Controlled, Randomized Trial of Selenium in Graves Hyperthyroidism2017
In 70 untreated Graves hyperthyroid patients over 24 weeks, add-on selenium 300 mcg/day did not improve response or relapse rates versus placebo with methimazole.
SupplementDEX Database · Hypothyroidism
9 references78.SupplementDEX Database: Hypothyroidism — Supplementation with myo-inositol and Selenium improves the clinical conditions and biochemical features of women with or at risk for subclinical hypothyroidism2022
In 148 women with subclinical hypothyroidism over 6 months, myo-inositol plus selenium (600 mg plus 83 mcg/day) improved TSH, autoantibodies, and symptoms.
79.SupplementDEX Database: Hypothyroidism — Interventions for clinical and subclinical hypothyroidism in pregnancy2010
A Cochrane review of 3 pregnancy hypothyroidism RCTs found insufficient evidence that selenium or other interventions clearly improve obstetric outcomes beyond levothyroxine.
80.SupplementDEX Database: Hypothyroidism — Randomized controlled trial of the effect of selenium supplementation on thyroid function in the elderly in the United Kingdom2008
In 501 elderly UK volunteers over 6 months, selenium 100–300 mcg/day did not significantly change thyroid hormone levels despite modest increases in plasma selenium.
81.SupplementDEX Database: Hypothyroidism — The influence of selenium supplementation on postpartum thyroid status in pregnant women with thyroid peroxidase autoantibodies2007
In 77 TPOAb-positive pregnant women, selenomethionine 200 mcg/day during and after pregnancy reduced postpartum thyroid dysfunction (28.6% vs 48.6%) versus placebo.
82.SupplementDEX Database: Hypothyroidism — Selenium status in an iodine deficient population of the West Ivory Coast2001
In iodine-deficient Ivory Coast populations, Glanlé residents had lower selenium, glutathione peroxidase, and vitamin E status than Abidjan controls, suggesting combined deficiency and oxidative stress.
83.SupplementDEX Database: Hypothyroidism — Selenium-induced thyroid dysfunction1997
A case report described IV high-dose selenite for sepsis causing marked hypothyroidism that normalized after iodine supplementation in a severely iodine-deficient patient.
84.SupplementDEX Database: Hypothyroidism — Low selenium status in the elderly influences thyroid hormones1995
In 109 healthy adults and a nursing-home trial, lower selenium status in elderly subjects correlated with lower T3/T4 ratios, supporting selenium's role in peripheral thyroid hormone conversion.
85.SupplementDEX Database: Hypothyroidism — Selenium deficiency mitigates hypothyroxinemia in iodine-deficient subjects1993
In iodine- and selenium-deficient Zaire subjects, selenium supplementation could worsen hypothyroxinemia by increasing T4 deiodination unless iodine or thyroid hormone is also provided.
86.SupplementDEX Database: Hypothyroidism — Effect of selenium supplementation in hypothyroid subjects of an iodine and selenium deficient area: the possible danger of indiscriminate supplementation of iodine-deficient subjects with selenium1991
In northern Zaire, 2 months of selenium supplementation corrected GPX activity but worsened thyroid function in clinically hypothyroid iodine-deficient subjects.
SupplementDEX Database · Kidney failure
3 references87.SupplementDEX Database: Kidney failure — Effect of selenium supplementation on lipid profile in hemodialysis patients2016
In 84 selenium-deficient hemodialysis patients over 3 months, selenium supplementation raised LDL cholesterol versus placebo, with no clear lipid benefit overall.
88.SupplementDEX Database: Kidney failure — Copper, selenium, zinc, and thiamine balances during continuous venovenous hemodiafiltration in critically ill patients2004
In 11 critically ill patients on continuous renal replacement therapy, copper, selenium, and zinc balances were often negative relative to recommended parenteral intakes.
89.SupplementDEX Database: Kidney failure — Influence of hemodialysis on selenium blood levels2000
In 95 hemodialysis patients, predialysis selenium levels were lower than controls and increased modestly after dialysis, with cuprophane membranes showing the largest post-dialysis rise.
SupplementDEX Database · Lichen planus
1 reference90.SupplementDEX Database: Lichen planus — Selenium: A sole treatment for erosive oral lichen planus (Randomized controlled clinical trial)2020
In erosive oral lichen planus over 6 weeks, topical or systemic selenium improved symptoms similarly to topical steroids, with topical selenium showing lower pain at 12 weeks.
SupplementDEX Database · Liver cancer
1 reference91.SupplementDEX Database: Liver cancer — A preliminary report on the intervention trials of primary liver cancer in high-risk populations with nutritional supplementation of selenium in China1991
Three Chinese liver cancer prevention trials found selenium-fortified salt or selenized yeast supplementation significantly reduced primary liver cancer incidence in high-risk populations.
SupplementDEX Database · Lymphedema
1 reference92.SupplementDEX Database: Lymphedema — Selenium for alleviating the side effects of chemotherapy, radiotherapy and surgery in cancer patients2006
A Cochrane review found insufficient high-quality evidence that selenium supplements reduce chemotherapy, radiotherapy, or surgery side effects in cancer patients.
SupplementDEX Database · Mercury toxicity
1 reference93.SupplementDEX Database: Mercury toxicity — Organic selenium supplementation increases mercury excretion and decreases oxidative damage in long-term mercury-exposed residents from Wanshan, China2012
In 103 mercury-exposed Wanshan residents over 3 months, selenium-enriched yeast 100 mcg/day increased urinary mercury excretion and lowered oxidative stress markers.
SupplementDEX Database · Muscular dystrophy
1 reference94.SupplementDEX Database: Muscular dystrophy — Selenium metabolism and supplementation in patients with muscular dystrophy1989
In Duchenne muscular dystrophy patients, selenium metabolism was normal and 1 mg/day sodium selenite did not change muscle glutathione peroxidase or disease activity.
SupplementDEX Database · Obesity
1 reference95.SupplementDEX Database: Obesity — Selenium Supplementation, Body Mass Composition, and Leptin Levels in Patients with Obesity on a Balanced Mildly Hypocaloric Diet: A Pilot Study2020
In 37 obese adults on a hypocaloric diet for 3 months, L-selenomethionine 240 mcg/day increased lean mass and lowered leptin versus placebo.
SupplementDEX Database · Oral health
1 reference96.SupplementDEX Database: Oral health — Effect of a multinutrient supplement as an adjunct to nonsurgical treatment of periodontitis: A randomized placebo-controlled clinical trial2024
In 42 periodontitis patients, a 2-month multinutrient supplement including alpha-lipoic acid as add-on to scaling showed some additional probing depth and bleeding-on-probing benefit versus placebo.
SupplementDEX Database · Oral mucositis
1 reference97.SupplementDEX Database: Oral mucositis — Effect of Selenium on Incidence and Severity of Mucositis during Radiotherapy in Patients with Head and Neck Cancer2020
In 71 head and neck cancer patients during radiotherapy, selenium 400 mcg/day did not reduce oral mucositis incidence or severity versus placebo.
SupplementDEX Database · Osteoarthritis
1 reference98.SupplementDEX Database: Osteoarthritis — Failure of selenium-ace to improve osteoarthritis1990
In osteoarthritis patients over 6 months, Selenium-ACE did not outperform placebo on joint symptoms, though both groups showed nonsignificant improvement trends.
SupplementDEX Database · Ovarian cancer
1 reference99.SupplementDEX Database: Ovarian cancer — A case-control study of diet and the risk of ovarian cancer2004
A Canadian case-control study found higher long-term vitamin E, beta-carotene, and B-complex supplement use associated with lower ovarian cancer risk.
SupplementDEX Database · Pancreatic cancer
2 references100.SupplementDEX Database: Pancreatic cancer — Serum selenium and pancreatic cancer: a prospective study in the Prostate, Lung, Colorectal and Ovarian Cancer Trial cohort2019
In 303 pancreatic cancer cases from PLCO, prediagnostic serum selenium was not associated with pancreatic cancer risk in this nested case-control analysis.
101.SupplementDEX Database: Pancreatic cancer — Association between selenium intake and the risk of pancreatic cancer: a meta-analysis of observational studies2016
A meta-analysis of 6 observational studies (1424 pancreatic cancer cases) found highest versus lowest selenium intake associated with 34% lower pancreatic cancer risk.
102.SupplementDEX Database: Polycystic ovary syndrome (PCOS) — Selenium supplementation effect on glycemic control: A GRADE-assessed systematic review and dose-response meta-analysis of randomized controlled trials2023
A meta-analysis of 20 RCTs found selenium supplementation lowered fasting insulin and raised QUICKI but did not significantly change fasting glucose or HbA1c.
103.SupplementDEX Database: Polycystic ovary syndrome (PCOS) — Effects of selenium supplementation on Polycystic Ovarian Syndrome: a systematic review and meta-analysis on randomized clinical trials2023
A meta-analysis of PCOS RCTs found selenium improved total antioxidant capacity but did not significantly improve BMI, testosterone, lipids, or insulin resistance overall.
104.SupplementDEX Database: Polycystic ovary syndrome (PCOS) — Selenium supplementation for polycystic ovary syndrome: a meta-analysis of randomized controlled trials2022
A meta-analysis of 5 PCOS RCTs found selenium supplementation lowered total testosterone and cholesterol versus placebo, with uncertain effects on other metabolic markers.
105.SupplementDEX Database: Polycystic ovary syndrome (PCOS) — The effects of selenium supplementation on glycemic control, serum lipoproteins and biomarkers of oxidative stress in infertile women diagnosed with polycystic ovary syndrome undergoing in vitro fertilization: A randomized, double-blind, placebo-controlled trial2022
In 40 infertile PCOS women over 8 weeks, selenium 200 mcg/day improved fasting glucose, insulin, HOMA-IR, and malondialdehyde but not pregnancy rate versus placebo.
106.SupplementDEX Database: Polycystic ovary syndrome (PCOS) — The Effects of Selenium Supplementation on Clinical Symptoms and Gene Expression Related to Inflammation and Vascular Endothelial Growth Factor in Infertile Women Candidate for In Vitro Fertilization2020
In 36 infertile PCOS women before IVF over 8 weeks, selenium 200 mcg/day downregulated IL-1 and TNF-alpha and upregulated VEGF gene expression versus placebo.
107.SupplementDEX Database: Polycystic ovary syndrome (PCOS) — The effects of probiotic and selenium co-supplementation on parameters of mental health, hormonal profiles, and biomarkers of inflammation and oxidative stress in women with polycystic ovary syndrome2018
In 60 PCOS women over 12 weeks, probiotic plus selenium 200 mcg/day improved depression and general health scores and lowered inflammation versus placebo.
108.SupplementDEX Database: Polycystic ovary syndrome (PCOS) — Selenium Supplementation and the Effects on Reproductive Outcomes, Biomarkers of Inflammation, and Oxidative Stress in Women with Polycystic Ovary Syndrome2016
In PCOS women, selenium supplementation improved reproductive and oxidative stress biomarkers in randomized trials, though specific outcomes varied across included studies.
109.SupplementDEX Database: Polycystic ovary syndrome (PCOS) — Metabolic response to selenium supplementation in women with polycystic ovary syndrome: a randomized, double-blind, placebo-controlled trial2015
In PCOS women, 8 weeks of selenium 200 mcg/day improved glucose homeostasis and lipid concentrations versus placebo in this randomized trial.
110.SupplementDEX Database: Postoperative recovery — Effect of High-Dose Selenium on Postoperative Organ Dysfunction and Mortality in Cardiac Surgery Patients: The SUSTAIN CSX Randomized Clinical Trial2023
In high-risk cardiac surgery patients, high-dose IV sodium selenite did not reduce postoperative organ dysfunction or mortality versus placebo.
111.SupplementDEX Database: Pregnancy-induced hypertension — Selenium supplement in the prevention of pregnancy induced hypertension1994
In 52 high-risk pregnant women, selenium 100 mcg/day for 6–8 weeks did not reduce pregnancy-induced hypertension versus placebo.
112.SupplementDEX Database: Premature rupture of membranes (PROM) — Selenium supplementation and premature (pre-labour) rupture of membranes: a randomised double-blind placebo-controlled trial2010
In 144 primigravid women, selenium 100 mcg/day through pregnancy did not reduce premature rupture of membranes versus placebo.
SupplementDEX Database · Rheumatoid arthritis
2 references113.SupplementDEX Database: Rheumatoid arthritis — Investigation of the Effect of Oral Selenium on the Reduction of Clinical Symptoms and Joint Pain in Patients With Rheumatoid Arthritis in the Iranian Population2023
In rheumatoid arthritis patients, oral selenium as adjuvant therapy reduced clinical symptoms and joint pain versus standard treatment alone in this randomized trial.
114.SupplementDEX Database: Rheumatoid arthritis — Selenium supplementation in rheumatoid arthritis investigated in a double blind, placebo-controlled trial2001
In a multicenter RA trial, selenium 200 mcg/day for 3 months did not improve tender/swollen joint counts or quality of life versus placebo.
SupplementDEX Database · Schizophrenia
1 reference115.SupplementDEX Database: Schizophrenia — The Effects of Probiotic and Selenium Co-supplementation on Clinical and Metabolic Scales in Chronic Schizophrenia: a Randomized, Double-blind, Placebo-Controlled Trial. See external source2021
In 60 chronic schizophrenia patients over 12 weeks, probiotic plus selenium co-supplementation improved metabolic and clinical scales versus placebo.
View source2021
SupplementDEX Database · Seborrheic dermatitis
2 references116.SupplementDEX Database: Seborrheic dermatitis — Selenium Disulfide-based shampoo applied for 4 weeks significantly improves dandruff and seborrheic dermatitis2023
In a 4-week international trial, selenium disulfide shampoo significantly improved dandruff and seborrheic dermatitis versus baseline.
117.SupplementDEX Database: Seborrheic dermatitis — Maintenance effect of a once-weekly regimen of a Selenium Disulfide-based shampoo in moderate-to-severe scalp seborrheic dermatitis after initial treatment with topical corticosteroid/salicylic acid2023
After 2 weeks of corticosteroid/salicylic acid treatment for scalp seborrheic dermatitis, once-weekly selenium disulfide shampoo reduced relapse versus observation.
SupplementDEX Database · Stomach cancer
3 references118.SupplementDEX Database: Stomach cancer — Meta-analysis of the association between selenium and gastric cancer risk2016
A meta-analysis found higher selenium exposure associated with lower gastric cancer risk, though heterogeneity across studies was substantial.
119.SupplementDEX Database: Stomach cancer — Fifteen-year effects of Helicobacter pylori, garlic, and vitamin treatments on gastric cancer incidence and mortality2012
At 14.7-year follow-up of the Shandong trial, H. pylori treatment reduced gastric cancer incidence; garlic and vitamin supplementation did not significantly reduce gastric cancer versus placebo.
120.SupplementDEX Database: Stomach cancer — Randomized double-blind factorial trial of three treatments to reduce the prevalence of precancerous gastric lesions2006
In 3,365 adults in Linqu County, China, 2-week H. pylori treatment reduced precancerous gastric lesions; 7 years of garlic or vitamin supplements did not significantly reduce lesion prevalence.
SupplementDEX Database · Stroke
2 references121.SupplementDEX Database: Stroke — Evaluation of Selenium Supplementation in Acute Ischemic Stroke Outcome: An Outcome Assessor Blind, Randomized, Placebo-Controlled, Feasibility Study2022
In acute ischemic stroke patients, selenium supplementation did not significantly improve functional outcomes versus placebo in this outcome-assessor-blind trial.
122.SupplementDEX Database: Stroke — Is Selenium Supplementation Beneficial in Acute Ischemic Stroke?2021
In acute ischemic stroke patients, IV selenium (Selenase) did not significantly improve clinical outcomes or glutathione peroxidase activity versus standard care in this trial.
123.SupplementDEX Database: Subarachnoid hemorrhage — Efficacy of Acetylcysteine and Selenium in Aneurysmal Subarachnoid Hemorrhage Patients: A Prospective, Multicenter, Single Blind Randomized Controlled Trial2023
A prospective multicenter, single-blind randomized controlled trial that evaluated high-dose intravenous sodium selenite (1,600 µg/day) plus acetylcysteine (2,000 mg/day) for 14 days, initiated within 24 hours of admission in patients with aneurysmal subarachnoid hemorrhage (aSAH). The study found a significant reduction in ICU stay but **no effect on radiological outcomes** such as edema volume, vasospasm or hydrocephalus.
SupplementDEX Database · Ulcerative colitis
2 references124.SupplementDEX Database: Ulcerative colitis — The effect of selenium supplementation on disease activity and immune-inflammatory biomarkers in patients with mild-to-moderate ulcerative colitis: a randomized, double-blind, placebo-controlled clinical trial2023
In 100 mild-to-moderate ulcerative colitis patients, selenium supplementation did not significantly reduce disease activity or inflammatory biomarkers versus placebo in this multicenter RCT.
125.SupplementDEX Database: Ulcerative colitis — An oral supplement enriched with fish oil, soluble fiber, and antioxidants for corticosteroid sparing in ulcerative colitis: a randomized, controlled trial2005
In ulcerative colitis patients, an oral supplement with fish oil, soluble fiber, and antioxidants did not significantly improve corticosteroid-sparing or disease activity versus control in this trial.