Additives & Dietary Supplements

Chondroitin sulfate is a sulfated glycosaminoglycan (GAG) composed of a chain of alternating sugars N-acetylgalactosamine and glucuronic acid). It is usually found attached to proteins as part of a proteoglycan. A chondroitin chain can have over 100 individual sugars, each of which can be sulfated in variable positions and quantities. Chondroitin sulfate is an important structural component of cartilage and provides much of its resistance to compression. Along with glucosamine, chondroitin sulfate has become a widely used dietary supplement for treatment of osteoarthritis.

Although chondroitin is used in dietary supplements as an alternative medicine to treat osteoarthritis and also approved and regulated as a symptomatic slow-acting drug for this disease (SYSADOA) in Europe and some other countries, it is technically neither a medicine nor a disease-modifying treatment. See Clinical effects below. It is commonly sold together with glucosamine. Chondroitin and glucosamine are also used in veterinary medicine. Formulated with collagen and wound dressing matrix, one product that uses chondroitin sulfate is the veterinary wound gel Chondroprotec, which is applied over scrapes, burns, and lesions and serves to keep the wound moist and promote healing.

Glucosamine (C6H13NO5) is an amino sugar and a prominent precursor in the biochemical synthesis of glycosylated proteins and lipids. Glucosamine is part of the structure of the polysaccharides chitosan and chitin, which compose the exoskeletons of crustaceans and other arthropods, as well as the cell walls of fungi and many higher organisms. Glucosamine is one of the most abundant monosaccharides. It is produced commercially by the hydrolysis of crustacean exoskeletons or, less commonly, by fermentation of a grain such as corn or wheat.

Oral glucosamine is a dietary supplement and is not a pharmaceutical drug. Glucosamine is marketed to support the structure and function of joints, and the marketing is targeted to pets suffering from osteoarthritis. Commonly sold forms of glucosamine are glucosamine sulfate, glucosamine hydrochloride, and N-acetylglucosamine. Of the three commonly available forms of glucosamine, only glucosamine sulfate is given a "likely effective" rating for treating osteoarthritis. Glucosamine is often sold in combination with other supplements such as chondroitin sulfate and methylsulfonylmethane.