Selenium supplement forms studied in human research
The clearest signal on this page is around thyroid Function Autoimmune Thyroiditis Hashimotos Thyroid Antibodies and type 2 Diabetes Glucose Insulin Resistance Metabolic Syndrome, but the evidence for other effects on this page is still mixed. Other uses here are narrower, weaker, or not clear enough yet.
What the research says
Each row is a different health effect. A means the support looks strongest, B likely helpful, C mixed or modest, and — not enough human evidence yet.
Papers are individual studies. Research reviews summarize evidence from multiple studies, such as systematic reviews and meta-analyses.
C · Mixed or limited evidence
C
Thyroid Function Autoimmune Thyroiditis Hashimotos Thyroid Antibodies
The research on thyroid Function Autoimmune Thyroiditis Hashimotos Thyroid Antibodies is mixed, modest, or both. Any claim here should stay narrow and specific.
11 papers · 8 research reviews
C
Type 2 Diabetes Glucose Insulin Resistance Metabolic Syndrome
The research on type 2 Diabetes Glucose Insulin Resistance Metabolic Syndrome is mixed, modest, or both. Any claim here should stay narrow and specific.
Research has been reviewed for cardiovascular Disease Blood Pressure Lipids Risk Markers, but the current human evidence is still too limited or inconsistent for a confident benefit claim.
6 papers · 3 research reviews
—
Male Fertility Sperm Quality Reproductive Hormones
Research has been reviewed for male Fertility Sperm Quality Reproductive Hormones, but the current human evidence is still too limited or inconsistent for a confident benefit claim.
4 papers
Safety
Safety is graded separately from benefits. Read these cautions first, especially if you take medication or have a medical condition.
✓ SafeNo clear harm signal in the human evidence reviewed.
✓
Side effects and tolerability
This is a safety note, not a benefit claim. It should not be read as a green light for every person or situation.
6 direct human studies
⚠ ConcerningThe human evidence points to a meaningful reason for caution.
⚠
Toxicity concerns
This is a safety note, not a benefit claim. It points to a real reason for caution.
1 direct human study
Quick facts
A quick read on what this page supports right now.
Health effects reviewed
4 health effects reviewed
Best grade shown
C · Mixed or limited evidence
Benefits with support
2 uses currently show some level of supportive evidence
Safety rows
2 separate safety or caution rows
Research volume
25 unique research papers across graded uses on this page
What this means
Keep any benefit claims limited to the specific graded uses shown here.
Quality-verified products
Products that pass third-party quality testing.
Product quality data coming soon
Any future product listings should stay aligned with the specific graded outcomes and the separate safety rows shown here.
How we graded Selenium
This page shows the current public rows for Selenium:
25 unique research papers across
4 visible health effects. Safety rows are shown separately from benefit rows when available. The page includes
14 review-level papers and
13 direct human studies. Each supplement is graded by health effect using a certainty × effect matrix applied across PubMed evidence per health effect. Cochrane reviews and high-quality systematic reviews carry the most weight. See
Methodology
for full detail.