Selenium

Minerals

Selenium

Selenium is a trace mineral and antioxidant that supports immune and thyroid function while protecting cells from oxidative stress. Supplementing may also promote healthy hair, skin and nails and support cardiovascular and reproductive health.

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Key Facts

Selenium is a trace mineral that acts as a cofactor for antioxidant enzymes, helping neutralize free radicals and protect cells from oxidative damage
Supports thyroid function and healthy aging by enabling the body's natural defense systems
This formulation uses selenomethionine, an amino acid-bound form with high bioavailability

Ingredients

Selenium (as L-selenomethionine) 200 mcg, hypromellose capsule, microcrystalline cellulose.

Why We Chose This

Selenium is essential for producing selenoproteins — enzymes that defend your cells against oxidative stress, much like how antioxidants in berries protect against cellular damage. Your thyroid also relies on selenium to function properly. Thorne's formulation uses selenomethionine, which your body absorbs and retains more effectively than other forms. At 200 mcg per capsule, this dose aligns with research supporting both antioxidant defense and thyroid health without exceeding safe upper limits.

Other Minerals

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Calcium

Calcium builds and maintains strong bones and teeth while supporting muscle function, nerve signaling, and a healthy heart rhythm. Supplementing may help reduce the risk of osteoporosis and fractures, ease muscle cramps, and support bone health as you age.

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Copper Bisglycinate

Copper Bisglycinate is a gentle, highly absorbable chelated copper supplement that supports immune function, energy production, and healthy connective tissue (collagen) formation. It may help with symptoms of copper deficiency—such as impaired iron metabolism, slow wound healing, low energy, and thinning hair—while supporting antioxidant enzyme activity, cardiovascular and cognitive health.

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Magnesium Bisglycinate

Magnesium bisglycinate is a highly absorbable, gentle-on-the-stomach form of magnesium that supports restful sleep, muscle relaxation, and nervous system balance. It may help reduce muscle cramps and tension, ease stress and anxiety, and support healthy sleep and bone metabolism.

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Magnesium CitraMate

Magnesium CitraMate is a fast-absorbing magnesium citrate supplement that supports muscle and nerve function, promotes relaxation and restful sleep, and helps maintain bone health and energy production. It may also help relieve occasional muscle cramps, tension, and mild constipation linked to low magnesium.

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Potassium Citrate

Potassium citrate is a potassium supplement that alkalinizes urine and restores citrate levels to help prevent the formation of kidney stones. It may also support electrolyte balance and healthy blood pressure, making it a smart daily choice for people prone to stone formation or low potassium.

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Zinc Bisglycinate 15 mg

Zinc Bisglycinate 15 mg is a chelated, highly absorbable form of zinc delivering 15 mg elemental zinc per dose. It supports immune defense, healthy skin and wound healing, hair and nail strength, and overall metabolic and reproductive wellness—helpful for those prone to frequent colds, slow healing, or thinning hair/nails.

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Frequently Asked Questions About Selenium

What is the supporting research for the benefits of selenium?

Adequate selenium status is associated with reduced risks of several cancers. (umbrella review)
Higher selenium exposure is associated with lower overall cancer risk. (cancer risk meta-analysis)
Selenium supplements are associated with improved sperm motility in some studies. (NIH fact sheet)

How do I take selenium?

Take 1 capsule daily with food to support your body's antioxidant defense and thyroid function.

Most people benefit from 55–200 mcg daily, though your specific needs depend on your current intake from food.

Can I take selenium with other supplements or medications?

Selenium can interact with certain medications like chemotherapy drugs, corticosteroids, and blood thinners, so check with your healthcare provider before combining. Most supplements pair safely with selenium, though high-dose antioxidants may reduce the effectiveness of some cholesterol medications.

Who might benefit from taking selenium?

People with low selenium levels, particularly those concerned about heart health, thyroid function, or aging, may benefit from supplementation. Those with limited dietary sources of selenium — including older adults and smokers — often see the most meaningful support.

How long does it typically take to notice effects of selenium?

Most people notice improvements in thyroid function and immune support within several weeks to a few months of consistent supplementation. Measurable changes in antioxidant markers can appear within 5–6 weeks, though subjective benefits typically emerge around the 3-month mark.

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