Comprising part of the glycosaminoglycan (GAG) fraction of the compound Aggrecan which together with Hyaluronan, Keratan Sulphate and collagen fibrils combines to make the structure of Articular Cartilage. Almost invariably used in conjunction with Glucosamine it is claimed to reduce the onset and severity of osteoarthritis by inhibiting enzymes which degrade articular cartilage. Sources include cattle tracheal cartilage, shark cartilage and mussels.
There is some evidence from in vitro laboratory studies that Chondroitin Sulphate and Glucosamine protect against cartilage matrix degradation. Studies in live horses have yielded mixed but generally weak results with perceived bias related to the supplement manufacturers financial support of the studies. Questions remain in regard to the bioavailability of oral supplements which may be low, and the subjective evaluation of lameness as measured in some studies.
Extensive studies in humans of Chondroitin Sulphate both in conjunction with, and without Glucosamine have been undertaken, involving thousands of patients mainly with knee and hip pain. Meta analysis of numerous studies concluded that when the trials were properly constituted and managed there was no difference in response between these two joint supplements and a placebo. There is insufficient evidence from credible trials in horses to support the use of either Chondroitin Sulphate or Glucosamine for the treatment or prevention of joint disease.