Biotin

Biotin (vitamin B7, formerly vitamin H) is a water-soluble B-vitamin that serves as a cofactor for carboxylase enzymes involved in fatty acid synthesis, amino acid metabolism, and gluconeogenesis. Biotin is essential for keratin production — the structural protein of hair, skin, and nails. While biotin deficiency clearly causes hair loss and brittle nails, evidence for supplementation benefits in individuals without deficiency is limited. High-dose biotin can interfere with certain laboratory tests, including thyroid panels and troponin assays.