Selenium for Hashimoto’s (Autoimmune) Thyroiditis and Hypothyroidism

A 2016 study found that significantly more patients with subclinical hypothyroidism (thyroid stimulating hormone TSH below 10 mU/L) and Hashimoto’s thyroiditis (thyroid peroxidase TPO antibodies) taking 83 mcg selenomethionine daily restored euthyroidism (TSH normalized) vs controls (31.3% vs 3.1%) over 4 months. TPO antibodies also significantly decreased in patients taking selenomethionine vs controls.

Another study in

2017 found that L-selenomethionine plus 600mg myo-

inositol was more effective than L-selenomethionine at decreasing TPO antibodies and improving TSH. Brazil nuts are one of the highest natural sources of selenium. The thyroid contains many selenium dependent proteins that help protect it from damaging free oxygen radicals and help with local activation of thyroid hormones. At high doses (> 400mcg daily), selenium can cause stomach discomfort, rash, fatigue or other side effects. Inositol can also cause stomach upset among other side effects.

Nordio M, Basciani S. Myo-inositol plus selenium supplementation restores euthyroid state in Hashimoto's patients with subclinical hypothyroidism. Eur Rev Med Pharmacol Sci. 2017 Jun;21(2 Suppl):51-59. PMID: 28724185.

Pirola I, Gandossi E, Agosti B, Delbarba A, Cappelli C. Selenium supplementation could restore euthyroidism in subclinical hypothyroid patients with autoimmune thyroiditis. Endokrynol Pol. 2016;67(6):567-571. doi: 10.5603/EP.2016.0064. PMID: 28042649.

“Office of Dietary Supplements - Selenium.” Nih.gov, 2025, ods.od.nih.gov/factsheets/Selenium-HealthProfessional