Selenium
Product Forms
Dose Distribution
Top Brands
Claims on Labels
Top-Rated Selenium Products
Evidence Summary
Selenium is an essential trace mineral with significant antioxidant and immune functions. While it is vital for health, large-scale clinical evidence regarding its ability to prevent major chronic diseases like cancer and cardiovascular disease is largely inconclusive or negative.
Evidence by Condition
Large-scale trials such as SELECT found no reduction in prostate cancer risk, and meta-analyses report inconsistent findings across different studies.
Cochrane reviews and meta-analyses do not support the use of selenium supplementation for the primary prevention of cardiovascular or coronary heart disease.
Research into selenium's role in Hashimoto's thyroiditis and autoimmune thyroid disease has yielded inconsistent results.
The PREADViSE trial found that antioxidant supplements, including selenium, did not significantly prevent dementia.
Effective Doses
Dose ranges are not explicitly stated in the provided research abstracts.
Key Findings
- The SELECT trial found no reduction in the risk of prostate cancer with selenium supplementation (PMID: 21990298).
- Cochrane reviews indicate no significant benefit for the primary prevention of cardiovascular disease (PMID: 23440843).
- Meta-analyses of selenium for cancer prevention have shown inconsistent conclusions (PMID: 22648711).
Limitations
High-quality evidence from large RCTs and Cochrane reviews often fails to demonstrate a significant preventive benefit for major chronic diseases, and results for autoimmune conditions remain inconsistent.
Safety & Interactions
Selenium is a trace mineral that possesses both nutritional and toxicological properties; excessive intake can lead to toxicity.
AI-generated summary from 273 peer-reviewed studies. Not medical advice. Always consult a healthcare provider.
Dietary Reference Intakes
Source: IOM/NAM Dietary Reference Intakes · Dietary Reference Intakes: Selenium
Drug-Supplement Interactions
⚠️ This information is for educational purposes only and does not constitute medical advice. Always consult your healthcare provider before combining supplements with medications.
Claims vs. Evidence
| Claim Type | % of Products | Evidence Required | Status |
|---|---|---|---|
| All Other | 98% | Tier D (Unclassified) | ✅ Supported |
| Structure/Function | 79% | Tier C (DSHEA Structure/Function (no pre-approval)) | ✅ Supported |
| Nutrient | 50% | Tier D (Unknown) | ✅ Supported |
| Qualified Health | 5% | Tier B (FDA Qualified Health Claim) | ✅ Supported |
| No Claim | 1% | Tier D (No claim on label) | ✅ Supported |
| Approved Health | 0% | Tier A (FDA Approved Health Claim (21 CFR 101.9)) | ⚠️ Unsupported |
🏛️ NIH ODS Factsheet
Research by Topic
⚠️ FDA Safety Data
Research Evidence (273)
BACKGROUND: This review is the third update of the Cochrane review "Selenium for preventing cancer". Selenium is a naturally occurring element with both nutritional and toxicological properties. Higher selenium exposure and selenium supplements have ...
BACKGROUND: Selenium is a key component of a number of selenoproteins which protect against oxidative stress and have the potential to prevent chronic diseases including cardiovascular disease (CVD). However, observational studies have shown inconsis...
BACKGROUND: Selenium is a trace mineral essential to health and has an important role in immunity, defence against tissue damage and thyroid function. Improving selenium status could help protect against overwhelming tissue damage and infection in cr...
CONTEXT: The initial report of the Selenium and Vitamin E Cancer Prevention Trial (SELECT) found no reduction in risk of prostate cancer with either selenium or vitamin E supplements but a statistically nonsignificant increase in prostate cancer risk...
BACKGROUND: Prostate cancer is a growing public health problem. Several human studies have shown a potentially protective effect of selenium, but the conclusions from published reports are inconsistent. OBJECTIVE: The objective was to examine the evi...
BACKGROUND: Hashimoto's thyroiditis is a common auto-immune disorder. The most common presenting symptoms may include anxiety, negative mood, depression, dry skin, cold intolerance, puffy eyes, muscle cramps and fatigue, deep voice, constipation, slo...
**Riley et al., 2017** | Cochrane Database Syst Rev | Meta Analysis Riley Philip, Glenny Anne-Marie, ... Worthington Helen V. Pharmacological interventions for preventing dry mouth and salivary gland dysfunction following radiotherapy. Cochrane Datab...
BACKGROUND: Antioxidants have been promoted for cardiovascular disease (CVD) risk reduction and for the prevention of cancer. Our preliminary analysis suggested that only when selenium was present were antioxidant mixtures associated with reduced all...
BACKGROUND: Selenium is a crucial mineral with antioxidant and immune functions, and selenium deficiency may increase the risk of coronary heart disease (CHD). However, the effect of selenium supplementation on CHD is still controversial according to...
**Wei et al., 2024** | Poult Sci | Meta Analysis Wei Chunbo, Wang Shuo, ... Zhang Ying. Meta-analysis of selenium effects on the meat quality of broilers. Poult Sci. 2024-Apr;103(4):103523. doi:10.1016/j.psj.2024.103523 The effects of sodium selenite...
**Stachika et al., 2026** | Nutrients | Systematic Review Stachika Nikolina, Tsarna Ermioni, ... Christopoulos Panagiotis. The Role of Selenium During Gestation in the Development of Fetal Congenital Anomalies: A Systematic Review. Nutrients. 2026-Fe...
IMPORTANCE: Oxidative stress is an established dementia pathway, but it is unknown if the use of antioxidant supplements can prevent dementia. OBJECTIVE: To determine if antioxidant supplements (vitamin E or selenium) used alone or in combination can...
**Xie et al., 2018** | BMJ Open | Systematic Review Xie Dongmei, Liao Yulin, ... Chen Ling. Effects of five types of selenium supplementation for treatment of Kashin-Beck disease in children: a systematic review and network meta-analysis. BMJ Open. 2...
BACKGROUND: This investigation systematically evaluated the selenium levels and the effects of selenium supplementation in patients with autoimmune thyroid disease (AITD). METHODS: Randomized controlled trials (RCTs) related to selenium supplementati...
**Fu et al., 2022** | Nutrients | Meta Analysis Fu Shaojie, Zhang Li, ... Xu Zhonggao. Effects of Selenium on Chronic Kidney Disease: A Mendelian Randomization Study. Nutrients. 2022-Oct-23;14(21). doi:10.3390/nu14214458 BACKGROUND: Previous observat...
BACKGROUND: Colorectal cancer (CRC) is a growing public health problem. Several clinical studies have shown a potentially protective effect of selenium (Se), but the reports are inconsistent. The objective of the study was to examine the evidence for...
BACKGROUND: To assess the clinical benefits of Selenium (Se) supplementation in patients with Hashimoto thyroiditis (HT). METHODS: Eight databases were searched for randomized controlled trials. The outcomes of interest were thyroid peroxidase antibo...
**Reid et al., 2013** | Cochrane Database Syst Rev | Meta Analysis Reid Sally M, Middleton Philippa, ... Bain Emily. Interventions for clinical and subclinical hypothyroidism pre-pregnancy and during pregnancy. Cochrane Database Syst Rev. 2013-May-31...
Background: Both experimental and observational studies have provided conflicting evidence on the associations of selenium with incidence and mortality of cardiovascular disease (CVD). The aim of this study was to evaluate the association between sel...
IMPORTANCE: Selenium and vitamin E have been identified as promising agents for the chemoprevention of recurrence and progression of non-muscle-invasive bladder cancer. OBJECTIVE: To determine whether selenium and/or vitamin E may prevent disease rec...
**Li et al., 2023** | Nutrients | Meta Analysis Li Jinjie, Li Hong, ... Kou Guangning. Causal Effect of Selenium Levels on Osteoporosis: A Mendelian Randomization Study. Nutrients. 2023-Dec-11;15(24). doi:10.3390/nu15245065 Prior research has demonst...
BACKGROUND: Selenium is a trace mineral essential to human health, which has an important role in the immune response, defence against tissue damage and thyroid function. Improving selenium status could help protect against overwhelming tissue damage...
Several studies have evaluated the possible association between antioxidants vitamins or selenium supplement and the risk of prostate cancer, but the evidence is still inconsistent. We systematically searched PubMed, EMBASE, the Cochrane Library, Sci...
**Dalal et al., 2017** | Cochrane Database Syst Rev | Meta Analysis Dalal Adam, Eskin-Schwartz Marina, ... Paul Mical. Interventions for the prevention of recurrent erysipelas and cellulitis. Cochrane Database Syst Rev. 2017-Jun-20;6(6):CD009758. doi...
**Zhou et al., 2018** | Biol Trace Elem Res | Meta Analysis Zhou Huihui, Wang Tong, ... Li Dandan. Prevention of Keshan Disease by Selenium Supplementation: a Systematic Review and Meta-analysis. Biol Trace Elem Res. 2018-Nov;186(1):98-105. doi:10.10...
**Ouyang et al., 2022** | Nutrients | Meta Analysis Ouyang Jiahui, Cai Yajie, ... Wang Anlu. Potential Benefits of Selenium Supplementation in Reducing Insulin Resistance in Patients with Cardiometabolic Diseases: A Systematic Review and Meta-Analysi...
**Issah et al., 2024** | Sci Total Environ | Systematic Review Issah Ibrahim, Duah Mabel S, ... Fobil Julius N. Exposure to metal mixtures and adverse pregnancy and birth outcomes: A systematic review. Sci Total Environ. 2024-Jan-15;908:168380. doi:1...
BACKGROUND: This review is an update of the first Cochrane publication on selenium for preventing cancer (Dennert 2011).Selenium is a metalloid with both nutritional and toxicological properties. Higher selenium exposure and selenium supplements have...
**Lin et al., 2022** | Nutrients | Meta Analysis Lin Yaduan, He Fanchen, ... Liu Chaoqun. Selenium Status in Patients with Chronic Liver Disease: A Systematic Review and Meta-Analysis. Nutrients. 2022-Feb-23;14(5). doi:10.3390/nu14050952 BACKGROUND: ...
**Fontenelle et al., 2022** | Clin Nutr | Meta Analysis Fontenelle Larissa Cristina, Cardoso de Araújo Diana Stefany, ... Marreiro Dilina do Nascimento. Nutritional status of selenium in overweight and obesity: A systematic review and meta-analysis. ...
Elevated levels of oxidative stress could cause and aggravate Alzheimer's disease (AD). Selenium (Se) is a trace element with antioxidant and anti-inflammatory activity with neuroprotective effects. To evaluate the effects of Se supplementation in pa...
**An et al., 2022** | J Am Coll Cardiol | Systematic Review An Peng, Wan Sitong, ... Liu Simin. Micronutrient Supplementation to Reduce Cardiovascular Risk. J Am Coll Cardiol. 2022-Dec-13;80(24):2269-2285. doi:10.1016/j.jacc.2022.09.048 BACKGROUND: H...
Background: Hashimoto thyroiditis (HT) is the most common cause of hypothyroidism in iodine-sufficient areas. Selenium is an essential trace element required for thyroid hormone synthesis and exerts antioxidant effects. Therefore, it may be of releva...
BACKGROUND: Protein Energy Malnutrition is an important cause of child morbidity and mortality in middle- and low-income countries. It has been suggested that excessive free radical activity may be responsible for the clinical manifestation of kwashi...
A low intake of selenium is associated with increased cardiovascular mortality. This could be reduced by supplementation with selenium and coenzyme Q10. D-dimer, a fragment of fibrin mirroring fibrinolysis, is a biomarker of thromboembolism, increase...
**Huang et al., 2024** | J Sci Food Agric | Meta Analysis Huang Ruilin, Bañuelos Gary S, ... Shen Lidong. Comprehensive evaluation of factors influencing selenium fertilization biofortification. J Sci Food Agric. 2024-Aug-15;104(10):6100-6107. doi:10...
**Krannich et al., 2024** | Complement Ther Med | Systematic Review Krannich Felix, Mücke Ralph, ... Dörfler Jennifer. A systematic review of Selenium as a complementary treatment in cancer patients. Complement Ther Med. 2024-Nov;86:103095. doi:10.10...
**Dennert et al., 2011** | Cochrane Database Syst Rev | Meta Analysis Dennert Gabriele, Zwahlen Marcel, ... Horneber Markus. Selenium for preventing cancer. Cochrane Database Syst Rev. 2011-May-11(5):CD005195. doi:10.1002/14651858.CD005195.pub2 BACKG...
**Krittanawong et al., 2021** | Am J Med | Systematic Review Krittanawong Chayakrit, Isath Ameesh, ... Tang W H Wilson. Mushroom Consumption and Cardiovascular Health: A Systematic Review. Am J Med. 2021-May;134(5):637-642.e2. doi:10.1016/j.amjmed.20...
**García-Esquinas et al., 2021** | Redox Biol | Meta Analysis García-Esquinas E, Carrasco-Rios M, ... Rodríguez-Artalejo F. Selenium and impaired physical function in US and Spanish older adults. Redox Biol. 2021-Jan;38:101819. doi:10.1016/j.redox.20...
**Nirooei et al., 2022** | Biol Trace Elem Res | Meta Analysis Nirooei Elahe, Kashani Seyyed Mohammad Amin, ... Akbari Hamed. Blood Trace Element Status in Multiple Sclerosis: a Systematic Review and Meta-analysis. Biol Trace Elem Res. 2022-Jan;200(1...
**Xu et al., 2022** | Diabetes Metab Res Rev | Meta Analysis Xu Wenhui, Tang Yiwei, ... Xie Lin. The association between serum selenium level and gestational diabetes mellitus: A systematic review and meta-analysis. Diabetes Metab Res Rev. 2022-May;3...
BACKGROUND: Selenium is an essential trace element with both beneficial and detrimental effects on health depending on dose and chemical form. Currently, there is debate on recommendations for selenium supplementation as a public health measure to im...
BACKGROUND: Evidence suggests that selenium supplementation could be useful in the treatment of Hashimoto thyroiditis (HT), but the available trials are heterogeneous. This study investigates clinically relevant effects of selenium supplementation in...
**Kamchen et al., 2024** | J Sci Food Agric | Meta Analysis Kamchen Camila Menezes, de Oliveira Fellipe Lopes, ... Morzelle Maressa Caldeira. Biofortification with selenium as an alternative to increase the total phenolic compounds in brassicas: a sy...
**Xu et al., 2016** | Biol Trace Elem Res | Meta Analysis Xu Min, Guo Dan, ... Lv Shuyan. Selenium and Preeclampsia: a Systematic Review and Meta-analysis. Biol Trace Elem Res. 2016-Jun;171(2):283-292. doi:10.1007/s12011-015-0545-7 Conflicting result...
**Kuria et al., 2020** | Crit Rev Food Sci Nutr | Meta Analysis Kuria Angelica, Fang Xin, ... Cao Yang. Does dietary intake of selenium protect against cancer? A systematic review and meta-analysis of population-based prospective studies. Crit Rev Fo...
**Xiang et al., 2020** | Biol Trace Elem Res | Meta Analysis Xiang Shouyan, Dai Zhe, ... Fan Yu. Circulating Selenium and Cardiovascular or All-Cause Mortality in the General Population: a Meta-Analysis. Biol Trace Elem Res. 2020-May;195(1):55-62. do...
**Zhang et al., 2021** | Int J Neurosci | Meta Analysis Zhang Yu-Jing, Sun Hua-Lei, ... Li Xing. Selenium level does not differ in blood but increased in cerebrospinal fluid in Parkinson's disease: a meta-analysis. Int J Neurosci. 2021-Jan;131(1):95-...
**Wang et al., 2023** | J Affect Disord | Meta Analysis Wang Huan, Jin Mengdi, ... Yu Qiong. Protective role of antioxidant supplementation for depression and anxiety: A meta-analysis of randomized clinical trials. J Affect Disord. 2023-Feb-15;323:26...
Showing top 50 of 273 sources, sorted by quality score.
Details
Selenium
Overview
Selenium is a essential nutrient tracked in the biomedical knowledge base.
Also known as: se, selenomethionine, sodium selenite, selenium yeast
Role in Health
Detailed overview pending — this entity has sources compiled across multiple verticals.
Related Verticals
See sources-index for all verified sources referencing Selenium.
Safety Considerations
Safety data extraction pending.
Sources
See linked source pages for full provenance.
Related Supplements
Frequently Asked Questions
What is selenium and why is it important?
Selenium is an essential trace mineral that plays a significant role in antioxidant and immune functions. It is a vital nutrient for maintaining overall health.
Can selenium supplements prevent cancer?
There is weak evidence to suggest that selenium can prevent cancer. Large-scale clinical trials, such as the SELECT trial, found no reduction in the risk of prostate cancer.
Does selenium help prevent heart disease?
There is weak evidence regarding selenium's ability to prevent cardiovascular or coronary heart disease. Major reviews have not found significant benefits for the primary prevention of these conditions.
Can selenium prevent dementia or memory loss?
There is weak evidence that selenium can prevent cognitive decline. Research like the PREADViSE trial indicates that antioxidant supplements, including selenium, did not significantly prevent dementia.
Is selenium effective for treating thyroid disease?
There is currently insufficient evidence to confirm selenium's role in treating autoimmune thyroid diseases like Hashimoto's thyroiditis. Research findings in this area have been inconsistent.
How much selenium should I take every day?
The recommended dietary allowance (RDA) for adults is 55 mcg per day. It is important to balance your intake to meet this nutritional requirement.
Is selenium safe, and can I take too much?
While selenium is a necessary mineral, excessive intake can lead to toxicity. Because it has both nutritional and toxicological properties, you should be careful not to exceed safe levels.
Are there any drug interactions with selenium?
There are currently no documented drug interactions for selenium. However, you should always consult a healthcare professional before starting any new supplement.
Answers generated from research evidence. Not medical advice.