The Study
The Impact of Selenium Deficiency and Supplementation on Hashimoto's Thyroiditis: A Clinical Evaluation.
This study looked at people who already had Hashimoto's and checked their selenium levels before and after taking supplements. It found that selenium went up, but so did some antibodies — but that doesn't mean the supplement caused it. It's like noticing ice cream sales go up when more people swim — they're connected, but one doesn't cause the other.
Analysis score
Maximum 44 for a cross-sectional study.
Where the score came from
Some people with Hashimoto's have low selenium, so doctors thought giving them selenium pills would calm their immune system. But this study found that while selenium levels went up, their immune attacks on the thyroid got stronger, not weaker.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 544 / 100
Quality score
Snapshots of a population at a single point in time, or descriptions of small groups. Can identify correlations and prevalence, but cannot determine cause and effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Higher selenium didn't help thyroid function or reduce autoimmune damage — it might even make it worse.
- 2Selenium went from 68.6 to 104.9 µg/L; anti-TPO antibodies went up by 1% (p=0.01); anti-Tg went up by 3% (p=0.03); TSH, FT3, and FT4 didn't change.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Endocrine, metabolic & immune disorders drug targets
Year
2026
Authors
Hasan Açık, Yusuf Aydin
Related Content
Claims (6)
In Hashimoto's disease, the immune system attacks the thyroid gland, leading to its gradual damage and reduced production of thyroid hormones.
In people with Hashimoto's thyroiditis, taking selenium supplements for six months raises selenium levels in the blood to sufficient levels and increases levels of two specific thyroid antibodies, while leaving thyroid hormone levels unchanged.
People with Hashimoto's thyroiditis have the same average levels of selenium in their blood as people without the disease.
In people with Hashimoto's thyroiditis, higher levels of selenium in the blood are associated with higher levels of anti-thyroid peroxidase antibodies.
Taking selenium supplements for six months does not change the levels of thyroid hormones in people with Hashimoto's thyroiditis.
In people with Hashimoto's thyroiditis, higher levels of selenium in the blood are linked to lower levels of the active thyroid hormone FT3.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.