Selenium is a mineral that is essential for health. It supports a range of body functions, including cardiovascular, immune, and cognitive functions.
Selenium is present in a variety of foods, including plant-based foods and animal products. People may also take selenium supplements to ensure they receive the optimal amount of this important nutrient.
This article describes what selenium is, including its benefits, side effects, and recommended daily dosage. We also provide a list of the 10 best selenium products available and tips on how to choose a selenium supplement. Finally, we answer some frequently asked questions about selenium.
Quick links
- Thorne Research Selenomethionine
- Pure Encapsulations Selenium (Selenomethionine)
- Life Extension Super Selenium
- NOW Selenium
- Nature’s Way Selenium Yeast-Free
- Bluebonnet Selenium
- NutraBio Selenium
- Vital Nutrients Selenium
- Nutricost Selenium
- Go Nutrients
What is selenium?
Selenium is a mineral that the body needs in small amounts to stay healthy. It is found in the following:
- plants grown in selenium-rich soilTrusted Source
- seafood
- meat
- poultry
- eggs
A person can also take selenium as a stand-alone supplement or as part of a multivitamin.
Selenium benefits
Selenium has both antioxidantTrusted Source and anti-inflammatory properties. It also plays an important role in thyroid function, reproduction, and immune health.
People undergoing kidney dialysis and living with HIV infection could be at risk for low levels of selenium.
Selenium side effects
Selenium supplements usually do not cause side effects unless taken in excess for a long time. If side effects do occur, the most common symptoms include:
- bad breath that smells like garlic
- changes to the hair and nails
- diarrhea
- nausea
- fatigue
- joint pain
Selenium overdose risks
Most people in the United States who eat a balanced diet have adequate levels of seleniumTrusted Source.
Brazil nuts contain so much selenium that someone who eats a lot of them regularly could accidentally consume too much selenium.
Selenium toxicity is rare and is usually related to inappropriate supplement dosing.
How much selenium to take per day
The recommended daily allowance (RDA) for selenium changes throughout a person’s life. Children and younger teenagers require less selenium compared to adults.
The National Institutes of Health (NIH)Trusted Source provide the following RDAs for selenium according to age:
- up to 6 months: 15 micrograms (mcg)
- 7 months to 3 years: 20 mcg
- 4–8 years: 30 mcg
- 9–13 years: 40 mcg
- 14 years and above: 55 mcg
The RDA for selenium also changes during pregnancy and lactation. The NIH states the RDA for selenium is 60 mcg for a pregnant person and 70 mcg for people who are lactating.
When to take selenium
It is best to take selenium supplements with meals, particularly if a person experiences issues with taking medications on an empty stomach.
How we chose
Medical News Today chooses products that meet the following criteria:
- Ingredients: MNT selects products containing safe and high quality ingredients that are clearly labeled. They should also confirm they are free from pesticides, heavy metals, and mold.
- Dosage: MNT chooses products that must clearly state the supplement dosage.
- Serving size: MNT selects products in which manufacturers recommend a safe dosage.
- Third-party testing: MNT chooses products that must undergo third-party testing for contaminants by an ISO 17025-compliant laboratory.
- Available certificate of analysis: MNT chooses companies that demonstrate transparency and share a product’s certificate of analysis (COA) following receipt of its third-party lab results.
Roundup of the best selenium supplements
Please note that the writer of this article has not tried these products. All information presented is purely research-based and correct at the time of publication.
MNT follows a strict product selection and vetting process. Learn more here.
Thorne Research Selenomethionine
Price: Around $10 for 60 capsules, approximately 17 cents per capsule.
Daily dose: 1 capsule.
Thorne Research Selenomethionine contains a form of selenium called selenomethionine. The body absorbs this form of selenium more readily than other forms of selenium.
The supplement does not contain the following:
- gluten
- soy
- dairy
- peanuts
- tree nuts
- yeast
- eggs
- fish
- shellfish
Thorne is certified by the Therapeutic Goods Association (TGA), a regulatory agency run by the Australian Government Department of Health.
The production facility is certified by NSF International, and Pure Encapsulations is certified by United States Pharmacopeia (USP), which sets strict product-specific standards for supplements.
One capsule contains 200 mcg of selenium, which is a common daily supplemental dosage.
Pure Encapsulations Selenium (Selenomethionine)
Price: Around $12.50 for 60 capsules, approximately 21 cents per capsule.
Daily dose: 1 capsule.
Pure Encapsulations Selenium (Selenomethionine) contains selenomethionine, the more bioavailableTrusted Source source of selenium.
This product does not contain the following:
- wheat
- gluten
- eggs
- peanuts
- tree nuts
- artificial colors, flavors, sweeteners, or preservatives
One capsule contains 200 mcg of selenium from non-genetically modified organism (GMO) sources.
Life Extension Super Selenium
Price: $10.50 for 100 capsules, approximately 10 cents per capsule.
Daily dose: 1 capsule.
Life Extension Super Selenium is a multi-supplement capsule containing the following:
- 200 mcg of selenium derived at least partially from yeast-free sources
- 20.1 milligrams of vitamin E
Manufacturers make the product in the U.S.
NOW Selenium
Price: $18.99 for 180 capsules, approximately 11 cents per capsule.
Daily dose: 1 capsule.
NOW Selenium contains 200 mcg of selenium, and is yeast and GMO-free. The capsules are also suitable for people with the following dietary requirements:
Nature’s Way Selenium Yeast-Free
Price: $9.79 for 100 capsules, approximately 10 cents per capsule.
Daily dose: 1 capsule.
Nature’s Way Selenium Yeast-Free is a gelatin capsule containing 200 mcg of selenium. The supplement does not contain the following:
- artificial colors and preservatives
- salt
- wheat
- corn
- gluten
- dairy
- sugar
- yeast
Bluebonnet Selenium
Price: $11.80 for 90 capsules, approximately 13 cents per capsule.
Daily dose: 1 capsule.
Bluebonnet Selenium is a vegetable-based capsule containing 200 mcg of selenium. The product is kosher and vegan. It does not contain the following:
- milk
- eggs
- fish
- crustacean
- shellfish
- peanuts
- tree nuts
- wheat
- soybeans
- corn
- yeast
- gluten
- barley
- rice
- sodium
- sugar
NutraBio Selenium
Price: $9.99 per 90 capsules, approximately 11 cents per capsule.
Daily dose: 1 capsule.
NutraBio Selenium contains 200 mcg of albion selenium, which is chelated to be gentler on the digestive system. The product is third-party tested.
NutraBio Selenium is suitable for vegetarians. It is also free from the following:
- GMO
- gluten
- soy
Vital Nutrients Selenium
Price: $24.80 for 90 capsules, approximately 28 cents per capsule.
Daily dose: 2 capsules.
Vital Nutrients Selenium is a capsule containing 200 mcg of selenium. However, the manufacturer recommends taking 2 capsules daily. Doing so would provide 400 mcg of selenium — the maximum daily upper limit (UL) of selenium.
Many selenium supplements only recommend a 200 mcg dose per day, so people may want to take only a single capsule per day to avoid an excessive dose.
The product is vegetarian and is free from the following:
- gluten
- dairy
- soy
- sugar
Nutricost Selenium
Price: $15.95 for 240 capsules, approximately 7 cents per capsule.
Daily dose: 1 capsule.
Nutricost Selenium capsules contain 200 mcg of selenium. The product is third-party tested and manufactured in a Good Manufacturing Practices compliant facility.
Nutricost Selenium is suitable for vegetarians. It is also free from the following:
- gluten
- soy
- GMO
Go Nutrients
Price: $19.95 for 100 doses, approximately 20 cents per dose.
Daily dose: 6 drops.
Go Nutrients is a liquid selenium supplement that features a dropper for delivering the supplement directly into the mouth. This product may be more suitable for people who have difficulty swallowing capsules.
Six drops provide a daily dose of 200 mcg of selenomethionine, which is the more bioavailable source of selenium.
The product is kosher, unflavored, and gluten-free.
Selenium supplement comparison
| Price | Dosage per capsule/liquid dose | Capsules/liquid drops per day | Product details | |
|---|---|---|---|---|
| Thorne Research Selenomethionine | $10; 17 cents/dose | 200 mcg | 1 capsule | selenomethionine, allergen-free |
| Pure Encapsulations Selenium (Selenomethionine) | $12.50; 21 cents/dose | 200 mcg | 1 capsule | selenomethionine, allergen-free, non-GMO |
| Life Extension Super Selenium | $10.50; 10 cents/dose | 200 mcg | 1 capsule | selenium from yeast-free sources, vitamin E |
| NOW Selenium | $18.99; 11 cents/dose | 200 mcg | 1 capsule | selenium from yeast-free sources, non-GMO |
| Nature’s Way Selenium Yeast-Free | $9.79; 10 cents/dose | 200 mcg | 1 capsule | selenium from yeast-free sources, allergen-free |
| Bluebonnet Selenium | $11.80; 13 cents/dose | 200 mcg | 1 capsule | selenium, allergen-free, non-GMO |
| NutraBio Selenium | $9.99; 11 cents/dose | 200 mcg | 1 capsule | albion selenium, GMO-free, gluten-free, and soy-free |
| Vital Nutrients Selenium | $24.80; 56 cents/dose | 200 mcg | 2 capsules | selenium. gluten-free, dairy-free, soy-free, and sugar-free |
| Nutricost Selenium | $15.95; 7 cents/dose | 200 mcg | 1 capsule | selenium |
| Go Nutrients | $19.95; 20 cents/dose | 200 mcg | 6 drops | selenium in liquid form |
How to choose a selenium supplement
When choosing a selenium supplement, people should consider the following:
- Dietary needs: People can check whether individual products are suitable for those following certain diets, such as vegetarian, vegan, or kosher diets.
- Interest in multi-supplements: Some selenium supplements contain additional micronutrients, such as zinc, copper, or Vitamin E.
- Supplement delivery method: Selenium drops are an option for people who are not comfortable taking capsules.
- Budget: Selenium supplements are available in a range of prices to suit most budgets.
Selenium toxicity symptoms
An excessive dose of selenium can cause toxic effects. The tolerable UL for a particular nutrient refers to the maximum amount of the nutrientTrusted Source that most people can take without adverse effects. The UL for selenium changes throughout a person’s life. For people over 14, the UL for selenium is 400 mcgTrusted Source.
The following are symptoms of consuming too muchTrusted Source selenium:
- bad breath that may smell like garlic
- metallic taste in the mouth
- spotted teeth
- brittle hair and nails
- potential hair and nail loss
- skin rash
- nausea
- fatigue
- irritability
When to contact a doctor
A person should consult with a doctor before taking supplements of any kind, particularly if they are taking other medications. Certain supplements can interact with certain medications, potentially causing adverse effects.
If a person notices any side effects while taking selenium, they should notify their doctor as soon as possible.
Frequently asked questions
Below are some common questions about selenium:
What is selenium good for?
Selenium is essential for human health. It supportsTrusted Source:
- the cardiovascular system
- the immune system
- thyroid function
- mental health
- cognitive health
- embryo development
Selenium may also help to prevent certain cancers.
What type of selenium is best?
There are two forms of selenium: Inorganic selenium, consisting of selenate and selenite, and organic selenium, consisting of selenomethionine and selenocysteine. According to the NIHTrusted Source, both forms can be good dietary sources of selenium.
However, the body more readily absorbs selenium supplements containing selenomethionine. According to the NIH, Trusted Sourcethe body takes in more than 90% of seleniumTrusted Source from selenomethionine, compared to 50% of selenium from selenite.
Summary
Selenium is a mineral that humans need in small amounts to stay healthy. It supports a range of body functions, including cardiovascular, immune, and cognitive functions.
Selenium is present in various foods, including plants and animal products. A person can also take selenium as a stand-alone supplement or as part of a multivitamin supplement.
When choosing a selenium supplement, a person should consider various factors, including price, the type of selenium the product contains, and whether it meets their individual dietary requirements.
A person should always talk with a healthcare professional before taking a supplement, especially if they are taking other supplements or medications. Certain supplements and medications can interact with each other, causing adverse and potentially serious side effects.
