Graded against 178,763 supplements and 757 reviewed supplement and medication pairs, sourced from PubMed, FDA CAERS, openFDA, NIH DSLD
Biotin
VitaminLast updated April 2026
AVELOR SUMMARY
Biotin is a water-soluble B vitamin essential for fatty acid synthesis, gluconeogenesis, and amino acid metabolism. Despite massive marketing for hair, skin, and nails, our research shows biotin supplementation only helps if you're actually deficient, which most people aren't. The critical safety concern: high-dose biotin (>1,000mcg) interferes with laboratory blood tests, including troponin (heart attack marker) and thyroid panels, potentially causing dangerous misdiagnosis.
EVIDENCE GRADES
Biotin deficiency correction
Strong evidenceGrade A
Brittle nail improvementone small trial (PMID: 8477615)
Limited evidenceGrade C+
Hair loss (non-deficiency)No evidence in non-deficient individuals
No benefit foundGrade D
Skin healthNo evidence in non-deficient individuals
No benefit foundGrade D
WHAT IT DOES
Biotin is a cofactor for five carboxylase enzymes critical to metabolism: pyruvate carboxylase, acetyl-CoA carboxylases (1 and 2), propionyl-CoA carboxylase, and 3-methylcrotonyl-CoA carboxylase. True deficiency is rare in developed countries, biotin is widely distributed in foods and produced by gut bacteria.
Populations at risk: pregnant women (accelerated biotin catabolism), individuals on long-term anticonvulsants (carbamazepine, phenytoin), chronic alcohol users, and people consuming large amounts of raw egg whites (avidin binds biotin).
OPTIMAL DOSAGE
Adequate Intake: 30mcg/day (adults)
Deficiency correction: 2,500-5,000mcg/day
Hair/nails (if deficient): 2,500-5,000mcg/day
Most supplements sell 5,000-10,000mcg, 167-333x the AI with no evidence of benefit in non-deficient individuals
HIGH-DOSE BIOTIN INTERFERES WITH STREPTAVIDIN-BIOTIN IMMUNOASSAYS, causes FALSE troponin results (may miss heart attack) and FALSE thyroid results
SAFETY PROFILE
⚠️ CRITICAL: Laboratory Test Interference
This is biotin's most important safety concern. Biotin at doses ≥1,000mcg interferes with streptavidin-biotin immunoassays used in most clinical laboratories:
Troponin (heart attack marker): FALSE LOW results → may miss diagnosis of MI
Thyroid tests (TSH, free T4, free T3): May show FALSE hyperthyroid pattern
PSA (prostate cancer): FALSE LOW → may miss elevated PSA
BNP (heart failure marker): FALSE results
The FDA issued a safety communication in November 2017 about this interference. Patients taking high-dose biotin should stop supplementation 72 hours before any blood work.
Side Effects
No adverse effects from biotin itself at any dose
All safety concerns relate to lab test interference
Pregnancy & Lactation
Marginal biotin deficiency is common in pregnancy. The AI during pregnancy is 30mcg/day. Supplementation at this level is safe and often included in prenatals.
WADA Status
Not Prohibited
HOW AVELOR SCORES THIS
Products at 30-300mcg for general B-complex: score normally
Products at 5,000-10,000mcg marketed for "hair growth": flag with lab interference warning and "no evidence of benefit in non-deficient individuals"
Automatic blood test warning for any product containing >1,000mcg biotin
Marketing claims about hair/skin/nails without deficiency context get flagged
CLINICAL REFERENCES
Reference identifiers on this page are being re-verified against PubMed. Some may not yet link to the paper named beside them.
1.
, Colombo VE et al. Treatment of brittle fingernails with biotin.
Independently graded against 178,763 indexed supplements and 757 reviewed supplement and medication pairs, sourced from PubMed, FDA CAERS, openFDA, and NIH DSLD | Last updated: April 2026
Not medical advice. Based on published clinical research and systematic reviews.