NOW Foods Glucosamine & Chondroitin Extra Strength, 750/600mg Tabs, 120 ct.NOW® Extra Strength Glucosamine & Chondroitin combines two well-known joint support ingredients in their sulfate forms. Glucosamine is an essential building block for the formation of glycosaminoglycans (GAG’s) and proteoglycans, the main components of cartilage tissue. Chondroitin Sulfate is a glycosaminoglycan that has been combined with Glucosamine in this product for the support of proper joint mobility and comfort.