Best Glucosamine Sulfate contains pure glucosamine sulfate, as confirmed by HPLC testing. Glucosamine sulfate consists of glucosamine, an amino sugar extracted from "chitin," a component of shellfish skeletons. ("Chitin," the resilient polysaccharide that forms the structural framework of animal shells, is a long-chain polymer consisting of many glucosamine molecules linked together.) The purified glucosamine is then sulfated and stabilized with potassium chloride. Understanding Glucosamine Sulfate and Chondroitin Sulfate and Their Roles in Joints Cartilage contains connective tissue composed of cells (chondrocytes), protein fibers (chiefly collagen) and clusters of complex molecules called "proteoglycans." Proteoglycan molecules are formed from long proteins (polypeptides) with numerous side chains. (The proteoglycan structure looks like a bottle brush.) The attached side chains, chiefly chondroitin sulfate and keratin sulfate, are long polysaccharide molecules called "glycosaminoglycans.Glucosamine is a key component of keratin sulfate, and it can be converted to galactosamine, which, along with glucuronic acid, forms chondroitin sulfate. Product Benefits. Supports Joint Structure and Function. Dosage. As a dietary supplement, take 2 capsules twice daily, with or without food.