Benefits and risks for 2022

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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.

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Selenium is a mineral that the body needs in small amounts to stay healthy. It is found in the following:

A person can also take selenium as a stand-alone supplement or as part of a multivitamin.

Selenium benefits

Selenium has both antioxidant 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:

Selenium overdose risks

Most people in the United States who eat a balanced diet have adequate levels of selenium.

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.

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) 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.

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 bioavailable 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:

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:

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:

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.

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.

An excessive dose of selenium can cause toxic effects. The tolerable UL for a particular nutrient refers to the maximum amount of the nutrient 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 mcg.

The following are symptoms of consuming too much 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

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.

Below are some common questions about selenium:

What is selenium good for?

Selenium is essential for human health. It supports:

  • 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 NIH, both forms can be good dietary sources of selenium.

However, the body more readily absorbs selenium supplements containing selenomethionine. According to the NIH, the body takes in more than 90% of selenium from selenomethionine, compared to 50% of selenium from selenite.

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.