Chondoritin Sulfate "is a sulfated glycosaminoglycan (GAG) composed of a chain of alternating sugars (N-acetyl-galactosamine 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. Understanding the functions of such diversity in chondroitin sulfate and related glycosaminoglycans is a major goal of glycobiology. Chondroitin sulfate is a major 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."

Source - Wikipedia.org