Selenium for Hashimoto
Verdict: Published with Warning
Across 6 PubMed studies, the evidence for Selenium in Hashimoto grades Tier B — preliminary evidence. Effective, but with safety or population caveats.
B 🟡 B Preliminary Evidence Published with Warning
Why this grade7-layer evidence engine
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Scoring transparency
All scores computed by a 7-layer evidence engine — fully auditableRaw score 0.63
D
C
B
A
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← counter-evidence / ineffectiveeffective / strong evidence →
Final grade
B · Published with Warning
Confidence
79%
Broadly consistent
Evidence level
E1
Cochrane high-quality SR/MA
▸View the full decision path (audit trail)
- compute_raw_score — 加權公式: L2×0.30 + L3×0.25 + L5×0.25 + L11×0.10 + L1×0.10 = 0.627
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 高品質 SR/MA 顯示 positive (2 篇 > 1 negative)
- tier_strict_requirement_check — Tier 條件達標，未降階
- detect_disputes — 偵測到 0 個 hard + 0 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status
PubMed studies (6)L2 · primary research & systematic reviews
Selenium supplementation for Hashimoto's thyroiditis
Finding: Across 4 RCTs (n=463, unclear-to-high risk of bias) a meta-analysis was not feasible due to extreme heterogeneity (I2=99%); the pre-specified primary outcomes (quality of life, LT4 dose, costs) were not reported by any trial, and selenomethionine 200 ug lowered TPOAb in individual studies (e.g., MD -917 U/mL, 95% CI -1056 to -778) but of unclear clinical relevance.
View on PubMed Selenium Supplementation in Patients with Hashimoto Thyroiditis: A Systematic Review and Meta-Analysis of Randomized Clinical Trials
Finding: In 35 RCTs, selenium modestly lowered TSH in non-LT4-treated patients (SMD -0.21, 95% CI -0.43 to -0.02; 869 participants) and lowered TPOAb (SMD -0.96, 95% CI -1.36 to -0.56; 2358 participants) with GRADE moderate certainty, but produced NO significant change in FT4, T4, FT3, T3, TGAb or thyroid volume.
View on PubMed Selenium supplementation and placebo are equally effective in improving quality of life in patients with hypothyroidism
Finding: In this pivotal multicentre double-blind RCT (412 randomized, 332 completed), 200 ug/day selenium-enriched yeast did NOT improve any ThyPRO-39 quality-of-life scale versus placebo at 12 months (composite 28.8 vs 28.0, P=0.602), despite a small reduction in TPOAb (1995 vs 2344 kIU/L, P=0.016) that did not change LT4 dose or FT3/FT4 ratio.
View on PubMed The Effects of Selenium Supplementation in the Treatment of Autoimmune Thyroiditis: An Overview of Systematic Reviews
Finding: Overview of 6 systematic reviews (75 RCTs, only 1 SR rated high quality) found selenium reduced TPOAb in non-LT4 patients at 3 and 6 months (e.g., LT4-treated 6-month SMD -1.95, 95% CI -3.17 to -0.74) but not at 12 months, all on VERY LOW certainty of evidence, and did not endorse routine use.
View on PubMed Insufficient evidence to support the clinical efficacy of selenium supplementation for patients with chronic autoimmune thyroiditis
Finding: Pooling 23 trials, selenium lowered TPOAb (e.g., LT4-treated 6-month MD -407 IU/mL, 95% CI -624 to -191) and improved echogenicity, but produced NO significant change in TSH and significantly MORE adverse effects, leading the authors to conclude current evidence does not justify emerging use of selenium for autoimmune thyroiditis.
View on PubMed Clinical efficacy of selenium supplementation in patients with Hashimoto thyroiditis: A systematic review and meta-analysis
Finding: Across 7 controlled trials (n=342), selenium showed NO significant TPOAb change at 3 months (WMD -124, 95% CI -631 to 383, P=0.63) but significantly reduced TPOAb (WMD -284, 95% CI -553 to -15, P<0.05) and TgAb (WMD -160, 95% CI -293 to -26, P<0.05) at 6 months, with very high heterogeneity (I2>93%) and no quality-of-life or disease-progression outcomes assessed.
View on PubMed Regulatory & authoritative positionsL4/L5 · FDA / EMA / NIH ODS / Cochrane / Mayo …
L4a US FDA
Cautious
Selenium may reduce the risk of certain cancers. Some scientific evidence suggests that consumption of selenium may reduce the risk of certain forms of cancer. However, FDA has determined that this evidence is limited and not conclusive. source↗
L4b EU EFSA
Supportive
Selenium contributes to normal thyroid function; contributes to the normal function of the immune system; contributes to the protection of cells from oxidative stress; contributes to normal spermatogenesis; contributes to the maintenance of normal hair; contributes to the maintenance of normal nails. source↗
L4c UK NHS
Cautious
75μg a day for men (19 to 64 years); 60μg a day for women (19 to 64 years). You should be able to get all the selenium you need by eating a varied and balanced diet that includes meat, fish or nuts. Taking 350μg or less a day of selenium supplements is unlikely to cause any harm. Too much selenium causes selenosis, a condition that, in its mildest form, can lead to loss of hair and nails. source↗
L4d TW TFDA / 衛福部
Supportive
形態屬膠囊狀、錠狀且標示有每日食用限量之食品，在每日食用量中，其硒之總含量不得高於200 μg。限於補充食品中不足之營養素時使用。 source↗
L4e WHO
Supportive
Prophylaxis consisting of oral administration of selenium 3 months before the periods of highest anticipated risk is highly effective. Once the disease is established, selenium is of little or no therapeutic value. source↗
L5a NIH Office of Dietary Supplements
Cautious
Selenium is a trace element that is naturally present in many foods, added to others, and available as a dietary supplement. Selenium, which is nutritionally essential for humans, is a constituent of more than two dozen selenoproteins that play critical roles in reproduction, thyroid hormone metabolism, DNA synthesis, and protection from oxidative damage and infection. source↗
L5b Mayo Clinic
Cautious
A balanced diet and other healthy lifestyle choices may help when you have Hashimoto's, but a specific diet alone is unlikely to reverse the changes caused by the disease. A healthy lifestyle that includes eating well, getting plenty of sleep, exercising regularly and limiting stress can benefit your immune system and could contribute to an improvement in your immune health. There's no evidence… source↗
L5c Cleveland Clinic
Cautious
Foods rich in selenium can help encourage healthy thyroid function. While some people with their provider's approval take a selenium supplement, most people can get enough selenium in their diet to help their thyroid work its best. If you go the way of supplements, stick to no more than 200 micrograms (mcg) per day. source↗
L5d Harvard Health
Cautious
The role of selenium supplementations for people with autoimmune thyroid diseases (ATD) is still unclear. A systematic review and meta-analysis of nine controlled trials did not find that selenium supplements changed thyroid hormone function in people with ATD, nor did a Cochrane review. source↗
L5e Specialty Society (condition-mapped)
Cautious
selenium supplementation in patients with Hashimoto's thyroiditis was associated with slightly reduced serum TSH levels and anti-TPOAb levels [...] further studies are needed to clearly examine the effect of selenium supplementation on slowing the onset of hypothyroidism. The strongest effect came from 200 μg/day of selenium for 6 months, reducing TSH from 3.24 to 2.4 mIU/L. no significant chan… source↗