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Yannis Lopez
Reviewed by Yannis Lopez · Nutrition Industry Veteran
Last updated: July 6, 2026
Thyroid & Immune Essential Mineral

Selenium

Thyroid, immune & antioxidant support

Essential trace mineral
Key for thyroid function

FDA Disclaimer: These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. Always consult your physician before starting any supplement.

Overview

Selenium is an essential trace mineral that plays a critical role in many bodily functions, particularly thyroid hormone metabolism, antioxidant defense, and immune system support. It is a key component of selenoproteins, which are important enzymes that protect cells from oxidative damage.

Selenium is found in soil and enters the food chain through plants and animals. Deficiency is relatively common in certain regions with low soil selenium levels. Supplemental selenium is often used to support thyroid health, immune function, and overall antioxidant status.

Potential Benefits

Thyroid Health

Essential for the conversion of T4 to active T3 thyroid hormone. Selenium deficiency is linked to thyroid disorders.

Antioxidant Defense

Key component of glutathione peroxidase, one of the body's most important antioxidant enzymes.

Immune Support

Supports immune cell function and may help regulate inflammatory responses.

Generally Well Tolerated

Selenium is safe at recommended doses. The upper limit is 400mcg daily. Excess can cause side effects.

Typical Dosage
Daily Dose
55–200mcg
Do not exceed 400mcg daily
Best Taken
With a meal
Can be taken any time of day
Pro Tips
  • Do not exceed 400mcg daily (upper limit)
  • Stack with Vitamin E for enhanced antioxidant effects
  • Especially important for those with thyroid concerns
  • Effects on thyroid function are usually noticed within 4–8 weeks
Research Snapshot

Selenium is well-established for its role in thyroid function and antioxidant defense. Multiple studies show that selenium supplementation can support thyroid health, particularly in autoimmune thyroid conditions. A 2016 meta-analysis of 16 controlled trials found that selenium supplementation significantly reduced thyroid peroxidase antibody levels in patients with chronic autoimmune thyroiditis, though its clinical significance remains uncertain.

How Selenium Compares

Ingredient Best For Key Difference
Selenium Thyroid, Antioxidant, Immune Essential mineral; key for selenoproteins
Zinc Immune, Hormone, Skin Essential mineral; supports 300+ reactions
Iodine Thyroid Hormone Production Essential for thyroid hormone synthesis

Selenium is often stacked with Zinc and Iodine for comprehensive thyroid and immune support.

Popular Stacks with Selenium
Thyroid Support Stack
Selenium + Zinc + Iodine
Excellent for thyroid health
Antioxidant Stack
Selenium + Vitamin E + Vitamin C
Great for cellular protection
Immune Stack
Selenium + Zinc + Vitamin D3
Popular for immune support

Full stack recommendations coming soon in our Stacks section.

Frequently Asked Questions
How long until I feel benefits?
Thyroid and immune benefits are usually noticed within 4–8 weeks of consistent daily use. Some people report improvements in energy and well-being within 2–4 weeks.
Can I take too much selenium?
Yes. The upper limit is 400mcg daily. Taking too much selenium over time can cause side effects like hair loss, nail changes, and gastrointestinal issues. Stick to recommended doses.
Should I take selenium if I have a thyroid condition?
Selenium is often recommended for thyroid support, especially in autoimmune thyroid conditions like Hashimoto's. However, always consult your physician before starting any supplement, especially if you have a thyroid condition or take thyroid medication.
Sources & References
  1. Wichman J, et al. Selenium Supplementation Significantly Reduces Thyroid Autoantibody Levels in Patients with Chronic Autoimmune Thyroiditis: A Systematic Review and Meta-Analysis. Thyroid. 2016;26(12):1681–1692.
  2. Rayman MP. Selenium and human health. Lancet. 2012;379(9822):1256–1268.
  3. Ventura M, et al. Selenium and Thyroid Disease: From Pathophysiology to Treatment. Int J Endocrinol. 2017;2017:1297658.
Related Ingredients
Zinc Vitamin E Vitamin D3 Magnesium
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