Selenium is an essential trace mineral found in soil, water, and some foods. It is an important factor in many body processes.
Selenium increases antioxidant effects in the body. Crab, fish, poultry, and wheat are generally good food sources. The amount of selenium in soil varies, and foods grown in different soils have different selenium levels. The Eastern Coastal Plain and Pacific Northwest have the lowest selenium levels in the US.
People commonly use selenium for selenium deficiency and to reduce the risk for high blood pressure during pregnancy. It is also used for prostate cancer, complications from statin drugs, abnormal cholesterol levels, cataracts, and many other conditions, but there is no good scientific evidence to support most of these uses. There is also no good evidence to support using selenium for COVID-19.
- Selenium deficiency.  Oral selenium is effective for the treatment and prevention of selenium deficiency.
Login for details
- Autoimmune thyroiditis.  Oral selenium seems to improve autoimmune thyroiditis in adults but not in children.
Login for details - Kashin-Beck disease.  Selenium seems to help prevent Kashin-Beck disease, but does not improve symptoms in patients with existing disease.
Login for details - Pre-eclampsia.  Oral selenium might reduce the risk of pre-eclampsia in pregnant patients.
Login for details
- Asthma.  Oral selenium does not seem to improve asthma symptoms.
Login for details - Atopic dermatitis (eczema).  Oral selenium-enriched yeast does not seem to improve eczema symptoms.
Login for details - Bladder cancer.  Despite promising initial research, oral selenium does not seem to prevent bladder cancer development or recurrence.
Login for details - Cardiovascular disease (CVD).  Most research shows that oral selenium does not reduce the risk of CVD.
Login for details - Colorectal cancer.  Oral selenium does not seem to prevent cancer of the colon and rectum.
Login for details - Diabetes.  Increased intake of selenium, either in the diet or as a supplement, is associated with an increased risk for developing type 2 diabetes.
Login for details - Dyslipidemia.  Most research shows that oral selenium supplementation does not improve cholesterol levels.
Login for details - Low birth weight.  Oral or intravenous selenium supplementation does not improve outcomes in low birth weight infants.
Login for details - Lung cancer.  Oral selenium does not reduce lung cancer risk in most patients.
Login for details - Nonmelanoma skin cancer.  Oral selenium does not reduce the risk of nonmelanoma skin cancer and has been linked to increased risk in some patients.
Login for details - Prostate cancer.  Oral selenium does not seem to reduce prostate cancer risk.
Login for details - Psoriasis.  Oral selenium does not seem to reduce psoriasis severity.
Login for details - Sepsis.  Intravenous selenium does not appear to improve outcomes in septic adults.
Login for details
- Age-related cognitive decline.  It is unclear if oral selenium reduces the risk of cognitive decline in older adults.
Login for details - Alcohol-related liver disease. Login for details
- Allergic rhinitis (hay fever). Login for details
- Arsenic poisoning.  It is unclear if oral selenized yeast is beneficial for patients that were exposed to high levels of arsenic in the environment.
Login for details - Benign prostatic hyperplasia (BPH).  Oral selenium has only been evaluated in combination with other ingredients; its effect when used alone is unclear.
Login for details - Burns.  Oral selenium has only been evaluated in combination with other ingredients; its effect when used alone is unclear.
Login for details - Cancer.  Selenium does not seem to reduce the risk of cancer in most people, but it might be beneficial in those with low selenium levels and in men.
Login for details - Cataracts.  Oral selenium has only been evaluated in combination with other ingredients; its effect when used alone is unclear.
Login for details - Cervical dysplasia.  It is unclear if oral selenized yeast is beneficial for patients with cervical dysplasia of mild severity.
Login for details - Chemotherapy-induced nephrotoxicity.  Oral selenium has only been evaluated in combination with other ingredients; its effect when used alone is unclear.
Login for details - Chronic fatigue syndrome (CFS). Login for details
- Cirrhosis.  Oral selenium has only been evaluated in combination with other ingredients; its effect when used alone is unclear.
Login for details - Cisplatin-associated ototoxicity.  Oral selenium has only been evaluated in combination with other ingredients; its effect when used alone is unclear.
Login for details - Colorectal adenoma.  It is unclear if oral selenium prevents recurrence of adenomas in the colon and rectum.
Login for details - Congestive heart failure (CHF).  Oral selenium has only been evaluated in combination with other ingredients; its effect when used alone is unclear.
Login for details - Coronary artery bypass graft (CABG) surgery.  It is unclear if oral selenized yeast is beneficial for patients undergoing CABG surgery.
Login for details - Critical illness (trauma).  Evidence on the use of intravenous selenium in critically ill patients is conflicting.
Login for details - Dementia.  It is unclear if oral selenium prevents dementia or reduces symptoms.
Login for details - Diabetic nephropathy.  It is unclear if oral selenium alleviates diabetic nephropathy symptoms.
Login for details - Dilated cardiomyopathy.  There is limited evidence on the oral use of selenium in patients with Keshan disease and peripartum cardiomyopathy.
Login for details - Esophageal cancer.  Limited research suggests that oral selenium does not reduce esophageal cancer risk.
Login for details - Gastric cancer.  Oral selenium has only been evaluated in combination with other ingredients and in a specific patient population; its effect when used alone and in other populations is unclear.
Login for details - Hepatitis C.  Oral selenium has only been evaluated in combination with other ingredients; its effect when used alone is unclear.
Login for details - HIV/AIDS.  It is unclear if oral selenium improves outcomes in patients with HIV.
Login for details - Hyperthyroidism.  It is unclear if oral selenium alleviates symptoms in patients with Grave's disease.
Login for details - Hypothyroidism.  It is unclear if oral selenium improves thyroid hormone balance in elderly or pregnant patients. In patients with iodine deficiency, selenium supplementation may be harmful.
Login for details - Influenza. Login for details
- Lichen planus.  It is unclear if topical or oral selenium alleviates oral lichen planus symptoms.
Login for details - Liver cancer.  It is unclear if oral selenium reduces liver cancer risk.
Login for details - Lymphedema.  It is unclear if oral selenium reduces lymphedema complications.
Login for details - Male infertility.  Oral selenium has only been evaluated in combination with other ingredients; its effect when used alone is unclear.
Login for details - Mercury toxicity.  It is unclear if oral selenium improves clearance of mercury and reduces symptoms of toxicity.
Login for details - Muscular dystrophy.  There is limited evidence on the oral use of selenium in Duchenne muscular dystrophy.
Login for details - Obesity.  It is unclear if oral selenium is beneficial for weight reduction.
Login for details - Oral mucositis.  It is unclear if oral selenium is beneficial for reducing oral mucositis in patients undergoing radiotherapy.
Login for details - Osteoarthritis.  Oral selenium has only been evaluated in combination with other ingredients; its effect when used alone is unclear.
Login for details - Ovarian cancer.  It is unclear if oral selenium reduces ovarian cancer risk.
Login for details - Overall mortality.  Although oral selenium does not seem to reduce overall mortality risk in most patients, it might have benefit in patients with low nutrient intake.
Login for details - Pancreatic cancer.  It is unclear if oral selenium reduces pancreatic cancer risk.
Login for details - Pancreatitis. Login for details
- Polycystic ovary syndrome (PCOS).  Oral selenium has only been evaluated in combination with other ingredients; its effect when used alone is unclear.
Login for details - Pregnancy-induced hypertension.  It is unclear if oral selenium reduces the development of hypertension during pregnancy.
Login for details - Radiation-induced diarrhea.  It is unclear if oral selenium reduces diarrhea in patients receiving radiation therapy for cancer.
Login for details - Rheumatoid arthritis (RA).  It is unclear if oral selenium, as selenized yeast, reduces RA symptoms.
Login for details - Statin-induced myopathy.  Small clinical studies suggest that oral selenium may not improve symptoms of myopathy in patients taking statins.
Login for details - Thyroid cancer.  It is unclear if oral selenium reduces the risk of thyroid cancer in most patients.
Login for details - Ulcerative colitis.  Oral selenium has only been evaluated in combination with other ingredients; its effect when used alone is unclear.
Login for details
When taken by mouth: Selenium is likely safe when taken in doses less than 400 mcg daily, short-term. But selenium is possibly unsafe when taken in high doses or for a long time. Taking doses above 400 mcg daily can increase the risk of developing selenium toxicity. Taking lower doses for a long time can increase the risk of developing diabetes.
Selenium can cause stomach discomfort, headache, and rash. High doses can cause hair loss, fatigue, nausea, vomiting, and weight loss. Extremely high doses can lead to organ failure and death.
Special Precautions & Warnings:
Pregnancy and breast-feeding: Selenium is possibly safe when used short-term in amounts that are not above 400 mcg daily. Selenium is possibly unsafe when taken by mouth in doses above 400 mcg daily. This dose might cause toxicity.Children: Selenium is possibly safe when taken by mouth appropriately. Selenium seems to be safe when used short-term in doses below 45 mcg daily for infants up to age 6 months, 60 mcg daily for infants 7-12 months, 90 mcg daily for children 1-3 years, 150 mcg daily for children 4-8 years, 280 mcg daily for children 9-13 years, and 400 mcg daily for children age 14 years and older.
Autoimmune diseases: Selenium might stimulate the immune system. People with autoimmune diseases such as multiple sclerosis, systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and other should avoid taking selenium supplements.
Hemodialysis: Blood levels of selenium can be low in people on hemodialysis. Selenium supplements might be needed for some people.
Under-active thyroid (hypothyroidism): Taking selenium can worsen hypothyroidism, especially in people with iodine deficiency. In this case, you should take iodine along with selenium. Check with your healthcare provider before taking selenium supplements.
Fertility problems in males: Selenium might decrease the ability of sperm to move, which could reduce fertility.
Skin cancer: In people who have had nonmelanoma skin cancer, long-term use of selenium supplements might slightly increase the risk of cancer returning. Avoid long-term use of selenium supplements if you have ever had skin cancer.
Surgery: Selenium might increase the risk of bleeding during and after surgery. Stop taking selenium at least 2 weeks before a scheduled surgery.
Birth control pills (Contraceptive drugs)
Interaction Rating=Minor Be watchful with this combination.
Some research shows that women who take birth control pills might have increased blood levels of selenium. But other research shows no change in selenium levels in women who take birth control pills. There isn't enough information to know if there is an important interaction between birth control pills and selenium.
Some birth control pills include ethinyl estradiol and levonorgestrel (Triphasil), ethinyl estradiol and norethindrone (Ortho-Novum 1/35, Ortho-Novum 7/7/7), and others.
Medications that slow blood clotting (Anticoagulant / Antiplatelet drugs)
Interaction Rating=Moderate Be cautious with this combination.
Selenium might slow blood clotting. Taking selenium along with medications that also slow clotting might increase the chances of bruising and bleeding.
Some medications that slow blood clotting include aspirin, clopidogrel (Plavix), dalteparin (Fragmin), enoxaparin (Lovenox), heparin, ticlopidine (Ticlid), warfarin (Coumadin), and others.
Medications used for lowering cholesterol (Statins)
Interaction Rating=Moderate Be cautious with this combination.
Taking selenium, beta-carotene, vitamin C, and vitamin E together might decrease the effectiveness of some medications used for lowering cholesterol. It is not known if selenium alone decreases the effectiveness of some medications used for lowering cholesterol.
Some medications used for lowering cholesterol include atorvastatin (Lipitor), fluvastatin (Lescol), lovastatin (Mevacor), and pravastatin (Pravachol).
Niacin
Interaction Rating=Moderate Be cautious with this combination.
Taking selenium along with vitamin E, vitamin C, and beta-carotene might decrease some of the beneficial effects of niacin. Niacin can increase the good cholesterol. Taking selenium along with these other vitamins might decrease the how well niacin works for increasing good cholesterol.
Sedative medications (Barbiturates)
Interaction Rating=Moderate Be cautious with this combination.
The body breaks down medications to get rid f them. Selenium might slow how fast the body breaks down sedative medications (Barbiturates). Taking selenium with these medications might increase the effects and side effects of these medications.
Warfarin (Coumadin)
Interaction Rating=Moderate Be cautious with this combination.
Selenium might thin the blood. Selenium might also increase the effects of warfarin in the body. Taking selenium along with warfarin might increase the chances of bruising and bleeding.
Astragalus: Some species of astragalus contain large amounts of selenium, especially when grown in selenium-rich soils. Taking products made from these plants along with selenium supplements could cause selenium poisoning. But most astragalus supplements contain Astragalus membranaceus, which does not contain high levels of selenium.
Copper: Selenium might increase how quickly the body removes copper. Taking selenium might reduce copper levels in the body.
Herbs and supplements that might slow blood clotting: Selenium might slow blood clotting and increase the risk of bleeding. Taking it with other supplements with similar effects might increase the risk of bleeding in some people.
Niacin: Niacin can increase good cholesterol levels. Taking selenium along with beta-carotene, vitamin E, and vitamin C might decrease the effects of niacin on good cholesterol levels. It is not known if selenium alone decreases the effects of niacin on good cholesterol levels.
Omega-3 fatty acids: Taking selenium with omega-3 fatty acids might reduce how much selenium the body absorbs.
Vitamin C: Taking vitamin C might affect how much selenium the body absorbs from some supplements. But it's unlikely that this is a big concern.
Zinc: Zinc might make it more difficult for the body to absorb selenium from food.
There are no known interactions with foods.
Selenium is an essential trace mineral found in foods, including crab, fish, poultry, and wheat. The amount of selenium in soil varies, so foods grown in different soils have different selenium levels. The amount that should be consumed on a daily basis is called the recommended dietary allowance (RDA). The RDA is 55 mcg daily for all people 19 years and older. While pregnant, the RDA is 60 mcg daily. While breastfeeding, the RDA is 70 mcg daily. In children, the RDA depends on age.
Atomic number 34, Dioxyde de Sélénium, Ebselen, L-Selenomethionine, L-Sélénométhionine, Levure Sélénisée, Numéro Atomique 34, Se, Selenio, Selenite, Sélénite de Sodium, Sélénium, Selenium Ascorbate, Selenium Dioxide, Selenized Yeast, Selenomethionine, Sélénométhionine, Sodium Selenite.
Natural Medicines disclaims any responsibility related to medical consequences of using any medical product. Effort is made to ensure that the information contained in this monograph is accurate at the time it was published. Consumers and medical professionals who consult this monograph are cautioned that any medical or product related decision is the sole responsibility of the consumer and/or the health care professional. A legal License Agreement sets limitations on downloading, storing, or printing content from this Database. Except for any possible exceptions written into your License Agreement, no reproduction of this monograph or any content from this Database is permitted without written permission from the publisher. Unlawful to download, store, or distribute content from this site.
For the latest comprehensive data on this and every other natural medicine, health professionals should consult the Professional Version of the Natural Medicines. It is fully referenced and updated daily.
© Copyright 1995-2021. Therapeutic Research Faculty, publishers of Natural Medicines, Prescriber's Letter, and Pharmacist's Letter. All rights reserved.