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meta analysis2,358 participants

Selenium for Hashimoto's Thyroiditis: What the Meta-Analysis Shows

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A 2024 systematic review and meta-analysis of randomized trials found selenium supplementation was associated with...

A 2024 systematic review and meta-analysis of randomized trials found selenium supplementation was associated with significantly reduced thyroid peroxidase antibodies (TPOAb) in people with Hashimoto's thyroiditis (SMD −0.96), and lower TSH, independent of thyroid hormone replacement. TPOAb is a marker, however, and whether this changes clinical outcomes is less clear — so selenium should be used only under clinician supervision, not as a substitute for thyroid care.

Key Findings

  • Across 29 cohorts (2,358 participants), selenium supplementation was associated with a significant reduction in thyroid peroxidase antibodies (TPOAb; SMD −0.96, 95% CI −1.36 to −0.56).
  • Selenium was also associated with lower TSH and reduced oxidative-stress markers, independent of whether participants were on thyroid hormone replacement.
  • TPOAb is a biomarker of autoimmune activity; reducing it has not been clearly shown to change clinical thyroid function or the need for medication.
  • Heterogeneity between trials was high, and benefit may depend on a person's baseline selenium status.

Study Details

Selenium Supplementation in Patients with Hashimoto Thyroiditis: A Systematic Review and Meta-Analysis of Randomized Clinical Trials
Huwiler VV, Maissen-Abgottspon S, Stanga Z, Mühlebach S, Trepp R, Bally L, Bano A — Thyroid (2024)
Selenium was associated with significantly reduced TPOAb (SMD −0.96) and lower TSH in Hashimoto's, independent of thyroid hormone replacement.
2,358 participantsModerate

Practical Takeaway

Selenium has been studied for supporting thyroid health in Hashimoto's, and meta-analysis links it to lower thyroid antibodies (TPOAb). Importantly, TPOAb is a marker — lowering it has not been proven to change how the thyroid functions or to reduce the need for medication, so selenium is not a substitute for thyroid evaluation, monitoring, or prescribed treatment (do not stop levothyroxine). Selenium also has a narrow safe range; too much can cause toxicity (selenosis). Use it only with clinician supervision, ideally with knowledge of your selenium status.

Summary

A meta-analysis of randomized trials found selenium was associated with lower thyroid antibody (TPOAb) levels in Hashimoto's, though effects on clinical thyroid function are less certain.

Related Supplements

Selenium

Related Conditions

Immune Function

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Frequently Asked Questions

Does selenium help with Hashimoto's thyroiditis?

A meta-analysis found selenium was associated with lower thyroid antibodies (TPOAb) and TSH in people with Hashimoto's. However, antibody levels are a marker, and it is not clear that lowering them changes how the thyroid works — so selenium is best seen as a supportive option used under medical supervision.

Can selenium replace my thyroid medication?

No. Selenium is not a substitute for thyroid evaluation, monitoring, or prescribed medication such as levothyroxine. Do not stop or change thyroid medication on your own — work with your clinician.

How much selenium is studied, and is it safe?

Trials commonly used about 200 mcg/day, often as selenomethionine. Selenium has a narrow safe range, and too much can cause toxicity (selenosis), so dose and duration should be guided by a clinician, ideally with awareness of your baseline selenium status.

Does lowering thyroid antibodies actually matter?

It is not yet clear. The meta-analysis showed antibody reductions, but whether that translates into better thyroid function or fewer symptoms over the long term remains uncertain. This is why selenium should complement, not replace, standard thyroid care.

Continue Reading

Supplement Guide

Selenium

Bottom line: Selenium at 55-200mcg daily supports thyroid and immune health. Selenomethionine is the best supplemental form. One to two Brazil nuts daily is an effective whole-food alternative.

Condition Guide

Immune Function

References

  1. Huwiler VV, Maissen-Abgottspon S, Stanga Z, Mühlebach S, Trepp R, Bally L, Bano A (2024). Selenium Supplementation in Patients with Hashimoto Thyroiditis: A Systematic Review and Meta-Analysis of Randomized Clinical Trials. Thyroid. DOI PubMed
  2. Zhang H, et al. (2025). Clinical efficacy of selenium supplementation in patients with Hashimoto thyroiditis: A systematic review and meta-analysis. Medicine (Baltimore). DOI PubMed