Glucosamine is a compound found naturally in the body, prepared from glucose and the amino acid glutamine. Glucosamine is required to create a molecule which is used in the development and restoration of cartilage and other body tissues. Production of Glucosamine slows with age.

It is an amino sugar and a well known precursor in the biochemical combination of glycosylated proteins and lipids. Glucosamine makes up a very significant part of the exoskeletons of crustaceans as well as other arthropods. It is present in fungi and various higher organisms, and it is one of the most bountiful monosaccharides. Glucosamine is made commercially by the hydrolysis of crustacean exoskeletons.

Glucosamine is a popular and effective treatment for arthritis, or inflammation and deterioration of the joints. It is sold as a supplement in liquid or capsules, but is also used in some cosmetics and some sports drinks.

Glucosamine supplements also often contain another naturally occurring substance in cartilage, chondroitin sulfate. This compound helps cartilage remain soft and flexible. Another common compound give with glucosamine is Methylsulfonylmethane, or MSM. Glucosamine is commonly used as part of the treatment for osteoarthritis. In this condition, often affecting the knees, cartilage loses elasticity and becomes stiff and wears down. This leads to irritation, swelling, loss of range of motion and pain.

Since this is a disease associated with aging, the natural glucosamine needed for repairs is decreasing so supplements may be needed. Generally, glucosamine is believed to reduce the pain of knee osteoarthritis and also to reduce further damage to the knee joints. Most doctors suggest a trial period of three months to determine effectiveness. If there is no relief after this time, it is discontinued as ineffective. The most standard dose of glucosamine is 1500 mg per day of this supplement.