Biotin (B7)
Content by: OpenSupplement Editorial Team | Medical review: pending | Last updated: April 13, 2026
TL;DR
Essential B vitamin for metabolism and gene regulation
Popular for hair, skin, and nail health claims
Limited evidence for benefits in healthy people
True deficiency is rare in developed countries
High doses can interfere with important lab tests
Best for: those with confirmed biotin deficiency or brittle nails
What it is
Biotin, also known as vitamin B7 or vitamin H, is a water-soluble B vitamin that serves as a cofactor for several carboxylase enzymes involved in fatty acid synthesis, amino acid catabolism, and gluconeogenesis. It also plays important roles in gene regulation and cell signaling.
True biotin deficiency is rare in healthy adults because the vitamin is widely available in foods and is also produced by gut bacteria. However, certain populations including pregnant women, people with genetic disorders affecting biotin metabolism, and those consuming raw eggs regularly may have increased needs or reduced absorption.
What the research says
Limited Evidence for Cosmetic Benefits
Despite massive marketing claims, the evidence for biotin improving hair, skin, and nails in healthy individuals is quite limited. Most positive studies have been conducted in people with biotin deficiency or specific conditions like brittle nail syndrome.
Nail Health Research
The strongest evidence exists for nail health. A few small studies found that biotin supplementation (2.5 mg daily) improved nail thickness and reduced brittleness in people with fragile nails. One uncontrolled study of 45 patients with brittle nails found 63% showed improvement after 2-7 months of biotin supplementation.
Hair Growth Claims
Evidence for hair growth benefits is largely anecdotal. While biotin deficiency can cause hair loss, there's little scientific support for biotin supplementation improving hair growth in people with normal biotin status. Most hair, skin, and nail benefits attributed to biotin likely occur only when correcting an underlying deficiency.
Metabolism and Gene Expression
Biotin's well-established roles in metabolism and gene regulation are crucial for overall health, but these functions are typically met through normal dietary intake in healthy individuals. [1][2]
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Biotin (B7) on Amazon
Safety
Biotin is extremely safe with no established upper limit due to its water-soluble nature and rapid excretion. However, high-dose biotin supplements (≥10 mg daily) can interfere with certain laboratory tests, potentially leading to falsely low or high results for thyroid function tests, troponin (heart attack marker), and hormone assays. This interference can persist for days after stopping supplementation.
Interactions
• Laboratory test interference - High doses can affect thyroid tests, troponin, vitamin D, and hormone assays • Anticonvulsants - Some seizure medications may reduce biotin absorption • Raw egg whites - Contain avidin which binds biotin and prevents absorption • Generally safe with other vitamins and medications
Dosing
Adequate Intake: 30 mcg daily for adults (easily met through diet)
Hair/Skin/Nails: 2.5-10 mg daily, though evidence is limited for healthy individuals
High-Dose Supplements: Often contain 5-10 mg, which is 100-300 times the adequate intake
Timing: Can be taken with or without food; water-soluble so excess is excreted
Cost
Biotin is one of the most affordable vitamins available. Basic biotin supplements cost $8-15 per month depending on dosage. Higher-potency formulas (5-10 mg) are only slightly more expensive. Many multivitamins also contain adequate amounts of biotin for general health maintenance.
The bottom line
Biotin is an essential vitamin that's crucial for metabolism, but true deficiency is rare in healthy adults eating varied diets. While heavily marketed for hair, skin, and nail benefits, the evidence is weak for people with normal biotin status. It's generally safe and inexpensive, but the cosmetic benefits are likely overstated for most users. Those with brittle nails might see some benefit, but dramatic hair and skin improvements are unlikely unless correcting a deficiency.
References
- Office of Dietary Supplements - National Institutes of Health. Biotin Fact Sheet for Health Professionals. Updated March 29, 2021.
- Patel DP et al. A review of the use of biotin for hair loss. Skin Appendage Disord. 2017;3(3):166-169.
Sources for this page include published meta-analyses, systematic reviews, and NIH dietary supplement fact sheets. All claims reflect the evidence as of early 2026.
This is not medical advice. Consult your healthcare provider before starting any supplement, especially if you take medications.