Glucosamine & MSM 500/500 Vegetarian, 240 Vcaps, NOW FoodsNOW Glucosamine & MSM Vegetarian Capsules Glucosamine is an essential substrate for the formation of glycoaminoglycans (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