Biotin (Vitamin B7)
Cofactor for fatty acid synthesis and gluconeogenesis — strongest evidence for brittle nail syndrome and keratin infrastructure support.
Biotin (Vitamin B7) is a water-soluble B vitamin essential for fatty acid synthesis, gluconeogenesis, and amino acid metabolism. While true deficiency is rare, supplementation is popular for hair, skin, and nail health. Evidence is strongest for brittle nail syndrome; hair benefits are less proven but widely reported anecdotally.
Supports protein building blocks of hair and nails
Essential for energy metabolism
How Biotin works — from molecular targets to health outcomes. Click an edge to see supporting research.This visualization is in beta — pathways are being refined and expanded.
2500-5000mcg (2.5-5mg) for hair/nails
Can be taken without food
| Form | Type |
|---|---|
| 💊Biotin capsules or tablets | Recommended |
| 🍬Gummies | Alternative |
| 💊Combined hair/skin/nail formulas | Alternative |
Standalone biotin is most economical. Higher doses (5000-10000mcg) are common for cosmetic purposes.
Minimum: 12 weeks
Optimal: 24 weeks
Cycling: Not required
Note: Water-soluble, can be taken any time. Consistent daily use is key.
Improved nail thickness and reduced brittleness
May improve hair thickness and reduce shedding
Safe at normal doses; may help prevent deficiency
HIGH BIOTIN INTERFERES WITH LAB TESTS — stop 48-72 hours before bloodwork
May reduce biotin levels
Biotin deficiency despite supplementation
Tip: Reduce dose
Top studies from 40+ peer-reviewed papers
Sui Z et al. • Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia (2023)
“The results of this study provide the necessary quantitative information for both the rational clinical use of drugs and future clinical trials in primary progressive multiple sclerosis.”
Gaffney PJ et al. • Multiple sclerosis and related disorders (2025)
“Although meta-analysis showed no significant effect of vitamins A, B1, B6, B7, B12, and D on several visual parameters, improvements observed in individual studies point to the essential role of vitamin sufficiency in ON.”
Espiritu AI et al. • Multiple sclerosis and related disorders (2021)
“A moderate certainty of evidence suggests a potential benefit in favor of HDB administered for 12 to 15 months in terms of ITW25 in patients with PMS.”
Lira Neto FT et al. • Fertility and sterility (2021)
“We concluded that pooled results from studies including infertile men with clinical varicocele indicated that varicocelectomy reduced the SDF rates.”
Parks NE et al. • The Cochrane database of systematic reviews (2020)
“There are a variety of controlled trials addressing the effects of dietary interventions for MS with substantial variation in active treatment, comparator, and outcomes of interest.”
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