NOW® Vegetarian Glucosamine & MSM combines two well-known joint support ingredients in a vegetarian/vegan friendly formula that does not include shellfish-derived Glucosamine. Glucosamine is an essential building block for the formation of glycosaminoglycans (GAGs) and proteoglycans, the main components of cartilage tissue. These compounds attract water to form a joint cushion, providing lubrication and shock absorption. MSM (Methylsulfonylmethane) is an organic form of sulfur, a mineral necessary for the production of GAGs and proteoglycans.