Glucosamine is the main building block for semi-fluids that lubricate the joints. lucosamine is Glucosaminoglycan (GAG), a component of all human tissues, especially high in concentration in the cartilages. It is naturally synthesised by addition of an amino group to glucos, followed by acetylation. Its main contents are glucos, glutamine and sulphur.Glucosamine is an essential component for the body's synthesis of lubricants and shock absorbing mechanisms necessary to maintain and restore healthy joint performance. Chondroitin is a molecule that occurs naturally in the body. It is a major component of cartilage, the tough connective tissue that cushions the joints. Chondroitin helps to keep cartilage healthy by absorbing fluid (particularly water) into the connective tissue. It may also block enzymes that break down cartilage, and it provides the building blocks for the body to produce new cartilage. Glucosamine is often combined with Chondroitin, a molecule naturally present in cartilage, together they stimulate the creation of proteoglycans that lubricate and nourish joints. Chondroitin gives cartilage elasticity and is believed to prevent the destruction of cartilage by enzymes. Glucosamine and Chondroitin, combined together, are proven to act and help beneficially in case of osteoarthritis because of their ability to aid and repair the cartilage and prevent further damage.