Glucose is the main sugar that is found in the blood. Glucosamine is an amino sugar or monosaccharide which is formed by replacing an atom of oxygen with an atom of nitrogen. It is a simple molecule that is naturally derived from glucose by the body. It is one of the key ingredients in the production of cartilage. There are no natural food sources for glucosamine. As a supplement, it is usually made from the shells of crustaceans such as crabs, shrimp and lobsters. A substance known as chitin is extracted from the shells for use in dietary supplements. Glucosamine supplements have been found to be very helpful in treating osteoarthritis because it helps rebuild worn away cartilage in the joints. Additionally, athletes often take glucosamine dietary supplements as a way of preventing injury to tendons and muscles as they feel it strengthens both. Furthermore, some people believe that glucosamine makes an effective treatment for tendinitis.

A number of impressive studies have been done that have shown the efficacy of using 500 to 2000 mg daily of glucosamine as a treatment for osteoarthritis and the pain that accompanies it. As cartilage rebuilds, it helps relieve the bone against bone grinding that is so evident with this malady. Daily supplementation can help slow down the progression of osteoarthritis as well as osteochondritis, a term used to refer to degeneration and pain in the knees which is caused by damage to articular cartilage. In fact, results are so positive that some patients are able to treat knee pain entirely with dietary supplementation and forego knee surgery.

Generally speaking, glucosamine supplements have been found safe. One study indicated that people with diabetes might develop high blood sugar levels when taking glucosamine; however, this study was conducted on laboratory animals and not on humans. People who are allergic to shellfish might experience allergic reactions when taking glucosamine; however, there has only been one documented case of this.