The Study
Clinical Outcomes of Selenium Supplementation in Hashimoto's Thyroiditis Without Selenium Deficiency: A Large‐Scale Retrospective Cohort Study
This study looked at people who took selenium supplements and compared them to people who didn’t, and noticed that those who took it had more health problems later. But it didn’t randomly assign people to take it or not, so we can’t be sure the supplement caused the problems — maybe the people who took it were already sicker or had different habits.
Analysis score
Maximum 72 for a cohort study.
Where the score came from
Some people take selenium pills thinking it helps their autoimmune thyroid disease, but this study looked at people who already had enough selenium and found it didn't help — and might have made things worse.
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 559 / 100
Quality score
Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes — these are big increases in serious health risks like organ damage, chronic disease, and death, even though the thyroid wasn't helped.
- 2People taking selenium had 33% more new autoimmune diseases, 61% more Sjögren's syndrome, 169% more psoriasis, and 38% higher chance of dying over 5 years — plus their thyroid antibodies and TSH levels went up.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Endocrinology, Diabetes & Metabolism
Year
2026
Authors
Eman A Toraih, Sarah Yaghi, C. Ardis, Lori Tran, Ahmed Abdelmaksoud, R. Elshazli, Mohammad H. Hussein, Hinali Patel, E. Elmorsy, Jessan A. Jishu, H. Aiash, Manal S. Fawzy
Related Content
Claims (5)
In people with Hashimoto's thyroiditis who have normal selenium levels, taking selenium supplements daily for six months or longer is linked to sustained increases in thyroid antibodies and hormone levels over five years.
Among adults with Hashimoto's thyroiditis who have normal selenium levels, taking selenium supplements has been linked to a higher chance of developing other autoimmune conditions, including Sjögren's syndrome, over five years.
Among adults with Hashimoto's thyroiditis who have normal selenium levels, taking selenium supplements may be linked to a 63% higher chance of dying from any cause over five years, even though there is no evidence it increases the risk of thyroid cancer or the need for thyroid surgery.
For adults with Hashimoto's thyroiditis who have normal selenium levels, taking selenium supplements does not lower thyroid-stimulating hormone (TSH) or stop the condition from worsening to overt hypothyroidism, and may cause TSH levels to rise over time.
Among adults with Hashimoto's thyroiditis who have normal selenium levels, taking selenium supplements is linked to a 169% higher relative risk of developing psoriasis over five years.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.