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Selenium is a mineral that’s essential to health in numerous ways. Your body incorporates selenium into special types of proteins called selenoproteins.

Selenoproteins are needed for important functions, such as the production of thyroid hormones. Plus, they have anti-inflammatory and antioxidant effects (1).

Having low selenium levels has been associated with a number of negative health outcomes, including suppressed immune function and an increased risk of mortality, anxiety, infertility, heart disease, and more (2).

Selenium must be obtained through your diet and is found in both animal- and plant-derived foods, including meat, grains, Brazil nuts, fish, and eggs. However, selenium concentrations in both plant- and animal-derived foods vary due to fluctuations in soil selenium content (3).

Some people, including those who follow vegan diets, those with HIV, and people with kidney disease, are at risk of developing selenium deficiency (3, 4).

Moreover, research has shown that selenium supplements may be beneficial for boosting the health of your immune system and reducing symptoms related to certain health conditions, such as autoimmune thyroid disease (5, 6).

For these reasons, many people choose to supplement with selenium, either through taking a selenium supplement or a multinutrient supplement that contains selenium.

The brands that made this list are trusted by healthcare professionals and set strict standards for the quality and safety of their supplements.

The supplements on this list contain selenium in the form of selenomethionine, which has been shown to have superior absorption rates compared with other forms of selenium used in supplements, including sodium selenite (3, 7, 8).

Here are the 10 best selenium supplements for 2021.

Selenium is most commonly sold in capsule form. Here are some of the best selenium capsules on the market.

Klaire Labs Seleno Met

Price: $$

Klaire labs is a trusted supplement brand that offers professional grade, third-party tested nutrition supplements that are manufactured in compliance with Good Manufacturing Practices (GMP) implemented by the Food and Drug Administration (FDA).

GMP regulations ensure that supplement manufacturers take steps to ensure their products are safe and effective.

Seleno Met contains selenium in the form of L-selenomethionine‚ which has been shown to have superior absorption compared with other forms of selenium commonly found in supplements (3, 7, 8).

Seleno Met is free of common allergens like casein, shellfish‚ tree nuts‚ gluten‚ soybeans‚ and corn, and contains no artificial flavors, colors‚ or preservatives.

One capsule delivers 200 mcg of selenium.

Pure Encapsulations Selenomethionine

Price: $

Pure Encapsulations is a brand used by many healthcare professionals. It’s certified by the United States Pharmacopeia (USP), which sets strict product-specific standards for supplements (9).

The company also independently tests their products for potency, contaminants, and allergens. Additionally, it’s certified gluten-free and GMO-free (9).

One capsule delivers 200 mcg of selenium.

NOW Foods Selenium (yeast-free)

Price: $

NOW Foods is a supplement company that offers certified organic dietary supplements. NOW Foods’ selenium can be found in most natural food stores and even some larger grocery store chains.

The brand exceeds the FDA’s Good Manufacturing Practices (GMPs) for the dietary supplement industry and is certified non-GMO.

Now Foods Selenium (yeast-free) supplement contains the highly absorbable L-selenomethionine and is free from common allergens like gluten and soy.

One capsule delivers 200 mcg of selenium.

Bluebonnet Selenium

Price: $

Bluebonnet is a supplement brand that can also be found in many grocery and specialty stores.

It’s certified by NSF International, an organization that independently tests supplements for quality and potency and inspects manufacturing facilities.
Bluebonnet is also kosher and certified vegan, soy-free, and gluten-free. Bluebonnet Selenium contains selenomethionine for optimal absorption.

One capsule delivers 200 mcg of selenium.

Selenium is essential for the health and functioning of your immune system (10).

Many supplements used to support immune function contain selenium along with other important nutrients for immune health, including vitamin C and zinc.

Taking zinc long term can interfere with your absorption of copper and cause a copper deficiency. You may want to only take supplements containing zinc for 2 weeks or if you have a zinc deficiency and be sure to speak to your doctor if you have any concerns.

Here are some of the best selenium supplements for immune support.

NOW Foods EpiCor Plus Immunity

Price: $$$

NOW Foods EpiCor Plus Immunity supplement contains a potent combination of selenium, vitamin D3, zinc, and vitamin C — all of which are needed for a strong immune system.

The supplement also contains an ingredient called EpiCor, which is derived from a yeast called Saccharomyces cerevisiae.

EpiCor has been shown to reduce inflammation and support the body’s immune response in some small, limited research studies sponsored by Embria Health Sciences, the creator of EpiCor (11, 12).

Both studies had limitations, including a very small sample size. Thus, further research will be needed on EpiCor.

One capsule delivers 35 mcg of selenium.

Pure Encapsulations Nutrient 950 with NAC

Price: $$$

Pure Encapsulations Nutrient 950 with NAC is a supplement designed to support and protect your immune system and overall health.

This supplement contains selenium in the form of selenomethionine along with a number of other nutrients, including vitamin D, zinc, vitamin C, and B vitamins. What’s more, it contains N-Acetyl-L-Cysteine (NAC).

NAC is needed to make the master antioxidant glutathione, which aids in detoxification, helps regenerate vitamins C and E, and scavenges free radicals, protecting your body against oxidative damage (13).

Four capsules delivers 100 mcg of selenium.

Supplementing with selenium has been associated with improved prostate health in some studies and may help protect against prostate cancer in men with low blood levels of selenium (14, 15).

However, other studies have noted an association between selenium supplements and high grade prostate cancer (16).

It’s likely that selenium supplements have different effects on prostate health based on blood selenium levels, genetics, and other factors, and may only be beneficial for certain people.

For this reason, it’s important that you consult your healthcare provider if you’re interested in taking selenium for prostate health or prostate cancer prevention to ensure safety.

Pure Encapsulations SP Ultimate

Price: $$$

Pure Encapsulation SP Ultimate is meant to support the health of the male reproductive system.

It combines selenium in the form of Selenomax (yeast-bound L-selenomethionine) with saw palmetto, zinc, lycopene, curcumin, green tea extract, and other ingredients that may benefit prostate health (17, 18, 19, 20, 21).

Note that this product contains relatively little selenium and has a higher price point due to the other ingredients included. Three capsules deliver only 70 mcg of selenium.

Selenium works synergistically with other nutrients, including vitamin E (22).

Many multinutrient supplements contain selenium and vitamin E, as well as other vitamins, minerals, and plant compounds.

These supplements may be a good choice for people who need extra support because of dietary restrictions, illness, or other medical conditions that increase nutrient needs.

Here are some of the best multinutrient supplements that contain selenium.

Thorne Trace Minerals

Price: $

Thorne is a supplement company that takes quality seriously. Thorne is certified by the Therapeutic Goods Association (TGA), a regulatory agency run by the Australian Government Department of Health. Plus, their production facility is certified by NSF International (23).

Thorne Trace Minerals contains selenomethionine, as well as other minerals including zinc, boron, chromium, manganese, and molybdenum.

One capsule delivers 100 mcg of selenium.

Vital Nutrients Multi-Nutrients (no iron or iodine)

Price: $$$

Vital Nutrients is a trusted brand in the medical field, and for good reason. It produces high quality nutritional supplements that undergo independent laboratory testing to ensure quality and purity.

Vital Nutrients Multi-Nutrients with no iron or iodine is a great choice for a multivitamin that covers your daily needs for most nutrients, including selenium. Plus, it doesn’t contain iron or iodine, making it a smart choice for people who don’t need to supplement with those minerals.

Although supplementing with iodine and iron is recommended in those with deficiencies, it’s unnecessary for people with adequate levels and can even be harmful (24, 25).

Three capsules delivers 100 mcg of selenium.

Vital Nutrients Minimal and Essential

Price: $$

Vital Nutrients Minimal and Essential is a multinutrient supplement that contains powerful antioxidants, including selenium and vitamins A and C.

This supplement also contains other important nutrients, such as vitamins B12 and D, which many people need to supplement to prevent deficiency (26, 27).

One capsule delivers 125 mcg of selenium.

When searching for a selenium supplement, it’s important to understand that more isn’t necessarily better. In fact, taking too much selenium can be dangerous, which is why a tolerable upper intake level of 400 mcg per day has been set for selenium intake (3).

Although research shows that higher doses can be safely tolerated, it’s important to consult a qualified healthcare professional to assess your selenium needs before supplementing with selenium.

It should be noted that doses of 5,000 mcg and higher can cause toxicity and lead to respiratory distress, heart attack, and kidney failure (28).

Most selenium supplements contain between 25 and 200 mcg of selenium per serving — well under the set upper intake level.

When shopping for a selenium supplement, look for products that undergo independent testing for quality and try to purchase supplements from trusted sites whenever possible or directly from the manufacturer.

Although the body only needs small amounts of selenium for optimal functioning, making sure you get enough of this nutrient is essential for overall health.

Fortunately, there are many excellent selenium supplements available to consumers who may need an extra boost of this important mineral.

Speak with your healthcare provider to determine whether taking a selenium supplement is the right choice for your health and choose from one of the supplements above to ensure you’re taking a high quality product.