Glucosamine is used in the treatment of osteoarthritis, and comes in two forms - sulphate or hydrochloride.

The form that has been most extensively tested is the sulphate, but this does not necessarily mean the hydrochloride is ineffective. Glucosamine is made from crab, lobster or shrimp shells, so it should not be taken by people allergic to seafood.

Glucosamine is a natural amino sugar produced by the body and found in some foods. There is some evidence that it plays a role in the production, maintenance and repair of cartilage.  It stimulates the production of   glycosaminoglycans, important proteins found in cartilage, and proteoglycans, the water-holding molecules that make up cartilage.

Glucosamine is often offered in combination with other supplements such as chondroitin sulfate and methylsulfonylmethane (MSM).