Glucosamine is an essential substrate for the formation of glycosaminoglycans (GAG's) and proteoglycans, which are the main components of cartilage tissue. GAG's and proteoglycans trap and hold water, forming a dense fluid cushion within the joint and thus, provide lubrication and shock absorption. MSM (Methylsulfonylmethane) is a natural source of organic sulfur, a mineral necessary for the production of proteoglycans. NOW Foods unique and synergistic formula is suitable for vegetarians, because it contains only GreenGrown Glucosamine HCl from a vegetarian source and not from shellfish.Not manufactured with wheat, gluten, soy, milk, egg, fish, shellfish or tree nut ingredients.