Selenium

Support your immune system and thyroid health with Selenium, an essential mineral that helps protect your cells and keeps your body functioning at its best.

December 5, 2025
Author
Superpower Science Team
Reviewed by
Julija Rabcuka
PhD Candidate at Oxford University
Creative
Jarvis Wang

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.

Frequently Asked Questions About Selenium

What is the supporting research for the benefits of selenium?
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.