Essential Nutrient for Healthy Hair and Nails Dietary Supplement Biotin is an unnumbered member of the water soluble B-complex family, normally only required in minute amounts. Biotin is used as a cofactor of enzymes involved in fatty acid metabolism, gluconeogenesis, and amino acid catabolism, and is essential in maintaining metabolic homeostasis. Biotin plays an important role in metabolic functioning as a coenzyme carrier of activated carbon dioxide in the TCA cycle (also known as the Krebs cycle). In its coenzyme form, biotin synthesizes glucose from non-carbohydrate sources, and synthesizes and breaks down certain fatty acids and amino acids