The best selenium supplement


Three ounces of yellowfin tuna has over 90 micrograms of selenium which more than meets the daily requirement.

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Which selenium supplements are best?

Selenium may not be the most recognized amino acid, but it remains an important one to consider in your overall health regimen. Found primarily in fish, meat and nuts, selenium has antioxidant properties and is considered an important component of thyroid health. While many people get enough selenium from their diets, others face significant deficits that supplements fulfill.

Finding a quality selenium supplement includes many important considerations. For overall quality and absorption, Thorne Research Selenomethionine is the top choice.

What to know before you buy a selenium supplement

Different types of selenium supplements

There are two types of selenium available on the market. Organic selenium, which has better retention in the body, is commonly known as selenomethionine, selenocysteine and methylselenocysteine. Selenomethionine (SeMet) is a naturally occurring amino acid found in soybeans, cereal grains and Brazil nuts.

Inorganic selenium, which is more quickly removed from the body, is known as selenite and selenate. Selenate is the microform required by the body for nutritional benefit. 

Different delivery forms of selenium supplements

Selenium supplements come in both capsule and tincture form. Capsules usually include a gelatin component, and some manufacturers have included additional nutrients by adding small amounts of some fruits and vegetables.

Tinctures are another option that allows a concentrated form of selenium to be placed under the tongue with a dropper. Tinctures are more quickly absorbed by the body and are a viable alternative for people who have difficulty swallowing pills.

Maximum dosage of selenium supplements

Most adults should aim for 55 micrograms of selenium per day. Some selenium supplements offer 200 micrograms or more. Typically, this is not harmful, but the maximum daily dosage should never exceed 400 micrograms; otherwise, there is a risk of selenium toxicity.

Also, consider how much selenium your diet provides. If you eat a lot of seafood, eggs, cereal grains, meat such as chicken, turkey and ham, and Brazil nuts, you are likely getting the recommended daily dosage of selenium. For more information on key considerations for purchasing selenium supplements, check out the BestReviews selenium supplement buying guide.

What to look for in a quality selenium supplement

Third-party testing

As with many supplements, third-party testing is scarce. Some manufacturers, however, seek out independent testing organizations that confirm the potency and purity of their products. Look for selenium supplements that are certified by the National Sanitation Foundation (NSF), which has an almost 80-year history of testing consumer products around the world.


Selenium has a strong smell that can affect people with sensitivities to particular odors. Many manufacturers strive to mask the odor in the capsule form, but you should be aware of this, especially with tinctures.

Synthetic selenium supplements

Some selenium supplements are made from whole foods, such as fruits and vegetables. Fans of whole food supplements like that they are natural. However, selenium supplements made in a laboratory often offer more selenium per serving, so you may need to take less of the synthetic form. It really is a personal preference. Both deliver selenium, which is the main goal.

How much you can expect to spend on selenium supplements

Selenium supplements cost $5-$20 depending on the potency and number of required doses.

Selenium supplement FAQ

What are the health benefits of selenium?

A. Selenium has antioxidant properties that may impact cardiovascular health and the thyroid system. Some studies even make a connection to helping Alzheimer’s disease, asthma, and some forms of cancer. The ability of selenium to boost the immune system seems to be a key contributor.

What are the most common side effects of selenium supplements?

A. Few side effects are reported when selenium supplements are taken in proper doses and follow the manufacturer’s directions. Selenium toxicity has signs of nausea, brittle and discolored nails, garlic-smelling breath, brittle hair that falls out and overall fatigue. If you ever experience these signs, stop taking the selenium supplement and contact your health professional.

What’s the best selenium supplement to buy?

Top selenium supplement

Thorne Research Selenomethionine

Thorne Research Selenomethionine

What you need to know: Doctors and consumers approve this supplement with a well-absorbed form of selenium.

What you’ll love: It offers excellent results for thyroid issues, mental clarity, detoxification and an overall increase in energy. It is a high-quality bound form of amino acid.

What you should consider: Side effects should always be reviewed, but this supplement had minimal ones.

Where to buy: Sold by Amazon and iHerb

Top selenium supplement for the money

Solaray Selenium Capsules

Solaray Selenium Capsules

What you need to know: This well-known brand offers an easily absorbed form of selenium.

What you’ll love: These capsules are vegan, non-GMO and certified for purity. They support thyroid function and boost the immune system.

What you should consider: The dosage may not be enough for some consumers.

Where to buy: Sold by Amazon and iHerb

Worth checking out

Trace Minerals Ionic Selenium

Trace Minerals Ionic Selenium

What you need to know: This is a liquid form of selenium that is easy to take and cost-effective.

What you’ll love: This natural formula is vegan and non-GMO. Liquid selenium is highly absorbable and supports blood sugar levels, antioxidants and the cardiovascular system.

What you should consider: Some people prefer capsules to liquid dispensing.

Where to buy: Sold by Amazon and iHerb

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Steve Ganger writes for BestReviews. BestReviews has helped millions of consumers simplify their purchasing decisions, saving them time and money.

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