Biotin (Vitamin B7)
Commonly used for
Healthy AgingHair HealthNail Health
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What is it? / Overview
Biotin is a cofactor for enzymes involved in fat, carbohydrate, and protein metabolism. Supplementation effectively corrects true deficiency but evidence that it improves hair or nails in people without deficiency is very limited.
How is it used? / Administration
Form: D-Biotin
Typical dose studied: 30 mcg/day (Adequate Intake); 30–300 mcg/day for deficiency
Timing: With or without food
True biotin deficiency is uncommon. Laboratory test interference is the major safety concern — always flag for anyone getting bloodwork.
How well does it work? / Evidence
✓ Well-established
Who should avoid it?
Interacts with: Anticonvulsants may reduce biotin levels
Already taking it? CRITICAL: Stop high-dose biotin at least 48–72 hours before blood tests — it interferes with thyroid tests, troponin, and many other immunoassays.
Research & references
Patel DP et al. (2017). Biotin for hair loss review. Skin Appendage Disorders. Zhang Y et al. (2022). Biotin and glycemic control meta-analysis. Frontiers in Nutrition. NIH Office of Dietary Supplements: Biotin Fact Sheet.
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