Glucosamine is a natural aminosaccharide contained in the mucopolysaccharides that are widely distributed throughout the cartilage tissues and connective tissues of the body. It is also present in large amounts in glycoproteins and glycolipids. Because glucosamine is contained in large volumes in chitin (the main ingredient in the shells of crustaceans such as crabs and shrimp), YSK manufactures glucosamine by hydrolizing chitin. Glucosamine is a white crystalline powder with a bittersweet taste. Some of its biological functions resemble those of N-acetylglucosamine. Among its main functions, it (1) promotes the synthesis of mucopolysaccharides, which relieve osteoarthritis and build beautiful skin; (2) has an anti-inflammatory action; and (3) suppresses the proliferation of tumor cells. In the United States and Europe, glucosamine has drawn particular attention for its effectiveness in preventing and treating osteoarthritis.