Glucosamine is an essential substrate for the&ampnbsp;formation of glycoaminoglycans (GAG's) and proteoglycans, which are the main components of cartilage tissue.&ampnbsp; GAG's and proteoglycans trap and hold water, forming a dense fluid cushion within the joint and thus, provide lubrication and shock absorption.&ampnbsp; MSM (Methylsulfonylmethane) is a natural source of organic sulfur, a mineral necessary for the production of proteoglycans.*&ampnbsp; NOW's unique and synergistic formula is suitable for&ampnbsp;vegetarians, because it contains only Glucosamine from a vegetarian source and not from shellfish.&ampnbsp;