Supplement
Biotin
The hair-skin-nails B vitamin.
Biotin (vitamin B7) is marketed for hair, skin, and nails. We grade Biotin C on evidence and C for worth-it at about $5-8 per month.
Evidence
Worth it
Typical cost: $5-8/month
What it does
Biotin (vitamin B7) is marketed for hair, skin, and nails. True deficiency is rare, and evidence for cosmetic benefits in non-deficient people is weak.
What the research says
May help brittle nails
Evidence: emerging. A few small trials on nail thickness; hair evidence is mostly anecdotal.
DRAFT: real vitamin, weak cosmetic case.
Is it worth it?
DRAFT: cheap, but likely unnecessary.
Typical cost
$5-8/month
Common form, not a brand recommendation
Dosage contextestablished
RDA-level; megadoses have no established benefit.
Safety notes
High doses interfere with lab tests including troponin and thyroid panels; tell your doctor before bloodwork. Talk to your doctor. This page is information, not medical advice.
Longevity Lab Report
Biotin news, graded when it happens.
New studies, dose debates, and expert shifts on biotin, in one email a week. Free.
Changelog
Last updated 2026-10-15
- 2026-10-15|Batch 3 entry, DRAFT. Grades provisional; expert positions unsourced unless noted.