Biotin is a water soluble vitamin, generally classified as a B complex vitamin, also called vitamin B4. After the initial discovery of biotin, nearly forty years of research were required to establish it as a vitamin. Biotin is required by all organisms but can only be synthesized by bacteria, yeasts, molds, algae, and some plant species. Biotin is required as prosthetic group of enzymes involved in incorporation of carbon dioxide into organic compounds. Biotin has a MW of 244 Da.