Hormones, thyroid and fertility
Seleniumand Thyroid Peroxidase Antibodies (TPOAb)
Both sources here measured lower thyroid Peroxidase Antibodies (TPOAb).
How sure anyone can be
Moderate certainty, level 3 of 4Further research may change this.
The most certain of the two findings here; each record carries its own.
The numbers reported
One source’s range, drawn against its own line of no difference and scaled to its own numbers.
-1.36-0.96 standardised effect size-0.56
This range stays on one side of the no-difference line.
Two sources, newest first
What we read is the published abstract, not the full paper, so a blank below may still be printed in the paper itself. A fixed rule worked this out from the source’s own fields. Nobody checked this rating by hand.
Systematic review, 2025
Low certainty, level 2 of 4Clinical efficacy of selenium supplementation in patients with Hashimoto thyroiditis: A systematic review and meta-analysis.
Medicine (Baltimore). 2025;104(35):e44043. doi:10.1097/MD.0000000000044043. PMID:40898469.
- Number reported
- -0.46 standardised effect size
- Which way it went
- Lower
- Likely range
- -0.74 to -0.18
- Source’s own words
- standardized mean difference in TPOAb vs comparison, 3-month time-point
- Who was studied
- Patients with hashimoto thyroiditis
- Compared with
- not stated in the abstract
- Amount taken
- Not in the abstract
- For how long
- 91 days
- Disagreement between studies
- Not in the abstract
- Kind of record
- Journal article
How this rating was reachedstarts at High, 2 steps down: risk of bias and imprecision
- Starts at High
- Risk of bias brought it down to Moderatethe abstract reports no risk-of-bias or quality appraisal, so study limitations cannot be ruled outNot in the abstract
- Imprecision brought it down to Lowthe abstract does not state how many participants were pooledNot in the abstract
- Ends at Low2 steps down.
- Checked, nothing to step it down for
- indirectness
- Inconsistency
- No disagreement reported, and no count of studies behind it
Imprecision stops at the first check that applies; others may apply too.
Source saved; quote checked byte-for-byte against it by software; no signature.
Systematic review, 2024 · 29 studies pooled · 2,358 participants
Moderate certainty, level 3 of 4Selenium Supplementation in Patients with Hashimoto Thyroiditis: A Systematic Review and Meta-Analysis of Randomized Clinical Trials.
Thyroid. 2024;34(3):295-313. doi:10.1089/thy.2023.0556. PMID:38243784.
- Number reported
- -0.96 standardised effect size
- Which way it went
- Lower
- Likely range
- -1.36 to -0.56
- Source’s own words
- standardized mean difference in TPOAb vs control
- Who was studied
- Adult with hashimoto thyroiditis
- Compared with
- placebo
- Amount taken
- Not in the abstract
- For how long
- Not in the abstract
- Disagreement between studies
- I2 = 90%
- Kind of record
- Journal article
How this rating was reachedstarts at High, one step down: inconsistency
- Starts at High
- Inconsistency brought it down to Moderateheterogeneity across pooled studies is high (I² = 90%)Reported in the abstract
- Ends at ModerateOne step down.
- Checked, nothing to step it down for
- risk of bias, indirectness and imprecision
AI-reviewed & signed — an AI agent re-read this finding against the saved source and checked that the quote, the numbers, the units and the direction match it. No person read it. The owner authorised the agent to sign the batch with the owner's key, and every build rechecks that signature against these exact bytes.
What is still missing from these readings
- One do not say how many people took part.
- Amount taken — Not in the abstract.
- For how long — One of Two readings: Not in the abstract.
Something nobody wrote down is never a zero and never a guess.
Still to read for Selenium
Nine of the 20 things on our list for Selenium have no reading here yet:
- Depression
- Estimated VO2max
- Free thyroxine (fT4)
- Free triiodothyronine (fT3)
- High-sensitivity CRP
- Mood
- Oxidative stress (F2-isoprostanes)
- Plasma Selenium
- Thyroglobulin Antibodies (TgAb)
Still to read means nobody here has got to it, not that it was tried and did nothing or that no research exists. A pairing on no list is not a gap: we never set out to read it.
Read next
Selenium
Ten other questions read for it
Hormones, thyroid and fertility
30 questions read under it
Thyroid Peroxidase Antibodies (TPOAb)
No other ingredients read against it
Alphabetical, and by nothing else.
This is a library, not advice. No recommendation, no dose, no diagnosis, no ranking. We never ask about your symptoms, and nothing here is tailored to you.