Biotin is an unnumbered member of the B-complex family, normally only required in minute amounts. 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 noncarbohydrate sources, and synthesizes and breaks down certain fatty acids and amino acids. A deficiency of biotin may result in hair loss, skin rashes, and neurological impairment.