Appearex® stimulates epidermal cells and affects the protein structure called keratin found in skin, nails and hair. Biotin is directly involved in the production of keratin cells and is believed to increase the quantity of keratin-matrix proteins in the nail. Thus Appearex® likely improves nail strength by influencing the keratin structure. Biotin is a vitamin, specifically a member of the B-complex family of vitamins. It is commonly found in the foods you eat every day, though not at the levels needed to impact nail quality. Appearex was developed by Merz Pharmaceuticals.