Selenium and the Thyroid: Hashimoto and Graves Evidence
What trials, reviews and thyroid societies say about selenium for Hashimoto thyroiditis, Graves hyperthyroidism and Graves eye disease, with the strength of evidence and safety limits.
Content last updated . This page has not been medically reviewed.
Terms
Hashimoto thyroiditis is an autoimmune condition in which the immune system attacks the thyroid so it cannot make enough hormone; it is the main cause of an underactive thyroid in the UK, and treatment is usually levothyroxine tablets. [2] Graves hyperthyroidism is an overactive thyroid. Graves orbitopathy (eye disease) is its main outside-the-thyroid effect. [3] Selenium doses below are study amounts, never advice.Evidence labels used
Established role: selenium works in thyroid hormone metabolism. Mixed and insufficient mean reviews disagree or are too small. Biomarker means a blood test result; it is not the same as feeling better.What the research found
| Condition and source | What it found | Strength |
|---|---|---|
| Hashimoto, Cochrane review 2013 | 4 trials, 463 people, unclear to high risk of bias. Selenomethionine 200 mcg lowered antibodies in some trials, but the authors said clinical relevance was unclear and the evidence was incomplete. [4] | Insufficient |
| Hashimoto, meta-analysis of 35 studies, Thyroid 2024 | Selenium lowered TSH in people not on thyroid hormone (7 groups, 869 people) and lowered TPO antibodies (very different results between studies); no change in free T4, thyroglobulin antibodies or thyroid volume; side effects similar to control. Certainty rated moderate. [5] | Mixed; mostly biomarkers |
| Hashimoto, review cited by NIH ODS | Nine trials, 679 people: selenium 80 to 200 mcg a day for 3 to 12 months did not change TSH, ultrasound findings or quality of life; authors concluded evidence did not support use. [1] | Mixed |
| Hashimoto, practice survey 2018 (published 2020) | Only 20% of 147 European Thyroid Association members said the evidence warrants use, yet 65% used it at least occasionally. The paper states selenium is not recommended for Hashimoto according to current ETA guidelines. [6] | Opinion survey |
| Graves hyperthyroidism, GRASS trial 2026 | 430 people with newly diagnosed Graves disease took 200 mcg selenium or placebo for 24 to 30 months with antithyroid drugs. Non-remission was 54.6% vs 53.3% and quality of life did not differ. [7] | No good evidence of benefit (large placebo-controlled trial) |
| Mild Graves eye disease, 2011 trial | 159 people took selenium 100 mcg twice daily, or placebo, for 6 months; quality of life and eye involvement improved and progression slowed, with no adverse events seen. [8] | Promising but limited |
| Mild to moderate Graves eye disease, selenium-sufficient area, 2025 | 84 people, open-label, 6 months: no improvement in the main quality-of-life score; early gains at 3 months were not sustained. [9] | Mixed |
| Graves eye disease, meta-analysis 2026 | 5 trials, 303 people: selenium may improve the clinical activity score, but not consistently quality of life or vision; authors urged caution. [10] | Mixed |
What guidelines say
The 2021 European guideline on Graves eye disease says that in mild, active disease, control of risk factors, local treatments and selenium (in selenium-deficient areas) are usually sufficient. [3] Note the condition: selenium-deficient areas. The 2025 trial above was in a selenium-sufficient area. [9] For pregnancy, NIH ODS reports that the American Thyroid Association made a weak recommendation in 2017 against selenium for pregnant women with thyroid antibodies, based on moderate-quality evidence. [1] If you are trying to conceive, are pregnant or are breastfeeding, talk with your doctor first. See Pregnancy and breastfeeding.Frequently asked questions
Does selenium treat Hashimoto's disease?
No source we read shows that. Trials mainly show lower thyroid antibody levels, and a Cochrane review said the clinical relevance was unclear. [4] A 2024 meta-analysis found lower TSH and TPO antibodies, with moderate certainty, but no change in several other measures. [5]
Does selenium help Graves' disease?
In a 430-person trial of newly diagnosed Graves hyperthyroidism, selenium added to antithyroid drugs did not change remission rates or quality of life. [7]
Does selenium help Graves eye disease?
Results are mixed. A 2011 trial in mild disease was positive, [8] while a 2025 trial in a selenium-sufficient area found no 6-month benefit. [9]
Should I take selenium for thyroid antibodies?
That is a question for your endocrinologist. NIH ODS says more research is needed to understand selenium supplements in thyroid disease, particularly by sex and selenium status. [1]
Can I test my selenium level?
Blood selenium tests exist, and NIH ODS says serum or plasma of 8 mcg/dL or more is generally considered sufficient in healthy people. [1] A clinician needs to interpret a result with your history.
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Safety and limits
Ask a doctor or pharmacist before use if you take thyroid medicine, antithyroid drugs or chemotherapy (NIH ODS notes cisplatin can lower selenium levels). [1] See Medication interactions. Kidney or liver conditions, children and surgery were not addressed in the sources we read for this topic, so ask a clinician. Never change or stop a prescribed thyroid medicine on your own. Thyroid symptoms such as fatigue have many causes; see Thyroid problems and fatigue.
Iodine is the other mineral the thyroid depends on; see Minerals and thyroid health and Selenium.
References
- NIH Office of Dietary Supplements, Selenium: Fact Sheet for Health Professionals (US). The ODS site blocked direct download, so this was read from an Internet Archive copy captured 30 December 2025. Read 2026-10-23.
- NHS, Underactive thyroid (hypothyroidism) (UK). Read 2026-10-23.
- Bartalena L et al., The 2021 European Group on Graves' orbitopathy (EUGOGO) clinical practice guidelines, Eur J Endocrinol 2021 (abstract read). Read 2026-10-23.
- van Zuuren EJ et al., Selenium supplementation for Hashimoto's thyroiditis, Cochrane Database Syst Rev 2013 (abstract read). Read 2026-10-23.
- Huwiler VV et al., Selenium supplementation in patients with Hashimoto thyroiditis: a systematic review and meta-analysis of randomized clinical trials, Thyroid 2024 (abstract read). Read 2026-10-23.
- Winther KH et al., A 2018 European Thyroid Association survey on the use of selenium supplementation in Hashimoto's thyroiditis, Eur Thyroid J 2020 (abstract read). Read 2026-10-23.
- Cramon PK et al., Selenium supplementation in individuals with newly diagnosed Graves' hyperthyroidism: a double-blind, multi-centre RCT (GRASS), Eur Thyroid J 2026 (abstract read). Read 2026-10-23.
- Marcocci C et al., Selenium and the course of mild Graves' orbitopathy, N Engl J Med 2011 (abstract read). Read 2026-10-23.
- Ahn HY et al., Selenium vs control for Graves ophthalmopathy in a selenium-sufficient area: a randomized clinical trial, JAMA Ophthalmol 2025 (abstract read). Read 2026-10-23.
- Kostadinov N et al., Efficacy of selenium supplementation in Graves' orbitopathy: a systematic review and meta-analysis, J Clin Med 2026 (abstract read). Read 2026-10-23.
- EFSA Panel on Nutrition, Novel Foods and Food Allergens, Scientific opinion on the tolerable upper intake level for selenium, EFSA Journal 2023 (abstract read). Read 2026-10-23.