Essential B vitamin | Biotin is a water-soluble B vitamin that is an essential co-factor for a number of metabolic carboxylation reactions involved in metabolism. Recent studies have expanded biotin capsules by Pure Encapsulations metabolic role, claiming that the vitamin maintains healthy genetic expression of the many enzymes for which it is a cofactor. Clinical studies have indicated that biotin may adjust the cellular arrangement of the nail bed, helping to reinforce the keratin structure, promote strength and thickness, and reduce splitting.