Myth-buster
A meta-analysis of 10 studies on Hashimoto's found selenium plus myo-inositol failed to significantly lower thyroid antibody levels — despite 4 out of 5 prior studies pointing to a benefit from selenium alone.
The new null result doesn't overturn the strong existing evidence that selenium alone can reduce TPO antibodies, but it shows that combining it with myo-inositol may not add benefit, and the overall picture is now more contested than a simple 'selenium works' headline suggests.
Researchers pooled data from 10 case-control studies of people with Hashimoto's thyroiditis to see if supplements lowered thyroid peroxidase antibodies (a marker of autoimmune attack on the thyroid). The combination of selenium plus myo-inositol didn't meaningfully reduce these antibodies over six months — the result was statistically non-significant. This contradicts most earlier selenium-only studies, which generally showed a benefit; the caveat is that the present analysis tested a combination, not selenium alone, and the sample size was modest (10 studies).
Where this fits in the evidence
Pillser has synthesized 5 studies on Selenium for Reduced Thyroid Peroxidase Antibody Level — overall evidence strength: High.
Across 5 studies on selenium for reducing thyroid peroxidase antibody (TPOAb) levels, 4 reported beneficial effects and 1 was neutral. The two highest-quality meta-analyses both found moderate-to-large statistically significant reductions in TPOAb among patients with Hashimoto thyroiditis (e.g., SMD -0.80 at 6 months in one 2025 meta-analysis of 1,610 patients). Effects were typically observed at 3–6 months (median study duration 182 days), supporting sustained supplementation for antibody reduction.
The study
- Systematic Review
- n = 10
- 2024-12-04
- Frontiers in endocrinology
This is a plain-language summary of a research finding, not medical advice. Pillser surfaces research signals to help you decide what's worth investigating — always consult a qualified professional before changing what you take.