Glucosamine is an amino sugar normally produced in the human body. It is necessary for the construction and normal repair of connective tissue and healthy joint cartilage. Chondroitin sulfate also occurs naturally in the body. Like glucosamine, chondroitin is a building block of proteoglycans: large protein molecules that give cartilage elasticity. Chondroitin sulfate acts by attracting fluid into the proteoglycan molecules and stimulates collagen production. MSM is useful for helping keep joints healthy. Each serving contains 1500mg of Glucosamine Sulfate, 1200mg of Chondroitin Sulfate, and 1200mg of MSM.