Glucosamine is a major precursor and or building block of glycosaminoglycans (GAGs). GAGs include hyaluronic acid, chondroitin sulphate, keratan sulphate and others. Because chondroitin and keratan are sulphated at key sites, they are also referred to as polysulphated GAGs or PSGAGs.

GAGs and PSGAGs are components in the structural matrix of joints, which involve synovial fluid, cartilage, tendons, ligaments, bones, blood vessels and capillaries. They are also structural components of membranes in the digestive and respiratory tracts.

Hyaluronic acid and keratan sulphate are major and minor components, respectively, of synovial fluid. Synovial fluid is degraded and lost during inflammatory stresses but can be reestablished rapidly with oral glucosamine supplementation. Thus, glucosamine has the ability to decrease pain in articular joints, by replenishing synovial fluid and reducing friction through a repair or rebuilding process rather than inhibiting pain signals.

Proteoglycans, the major component of the cartilage matrix consists of hyaluronic acid, chondroitin sulphate and a protein branch linking the two. During inflammatory conditions, enzymes are released which degrade proteoglycans, leading to compromised articular cartilage function.

Glucosamine interferes with the action of these enzymes, reducing and containing the level of damage while supplying a vital raw material for rebuilding the proteogycan matrix.

Glucosamine is necessary for the manufacture of mucin, a crucial protective component of the digestive tract.

Glucosamine is a naturally occurring substance in the body normally found in high concentrations in the joint cavities.

Once it (ghcl) ''starts working'' it has been shown to be more effective than NSAIDS at relieving the symptoms of osteoarthritis, due to it's regenerative abilities with regards to the joint cavity and related structures. (Alt Med Rev 1998;3(1):27-39)