Glucosamine is an amino sugar (a combination of an amino acid – glutamine, and a sugar – glucose) normally found in healthy cartilage. It is synthesised by many cells in our body, but is concentrated in joint cartilage. Glucosamine functions as the basic building block of cartilage by first being a basic building block of glycosaminoglycans (GAG), which themselves make up very large structures known as proteoglycans. Without adequate glucosamine, proteoglycans synthesis by chondrocytes would shut down, and this in turn would cause the synthesis of cartilage to stop. Glucosamine makes up 50% of one of the most important GAGs,