Glucosamine is extracted from a material (chitin) present in the shells of crabs, oysters, and shrimp. Glucosamine is taken in tablet or capsule form, usually as glucosamine sulfate, but sometimes as glucosamine hydrochloride. Glucosamine often is taken with chondroitin sulfate Chondroitin Sulfate Chondroitin sulfate is a natural component of cartilage. It is extracted from shark or cow cartilage or manufactured synthetically. It is frequently combined with glucosamine. (See also Overview... read more .
(See also Overview of Dietary Supplements Overview of Dietary Supplements Integrative medicine and health (IMH) and complementary and alternative medicine (CAM) include healing approaches and therapies that historically have not been included in conventional, mainstream... read more .)
Medicinal claims
People take glucosamine mostly to treat osteoarthritis Osteoarthritis (OA) Osteoarthritis is a chronic disorder that causes damage to the cartilage and surrounding tissues and is characterized by pain, stiffness, and loss of function. Arthritis due to damage of joint... read more 
of the knee. Its role in treating osteoarthritis in other locations is less well defined. Evidence is conflicting. Some evidence suggests it has both pain-relieving and disease-modifying effects, whereas other large and well-designed studies show it to be of no benefit. One large study has shown that glucosamine hydrochloride is beneficial when combined with chondroitin sulfate. Evidence supports use of glucosamine sulfate from a specific manufacturer, Rotta Research Laboratorium, for mild to moderate osteoarthritis in the knee when taken for at least 6 months. The benefit of glucosamine for severe osteoarthritis in the knee or osteoarthritis in other locations is less clear.
Possible side effects
Glucosamine is safe for most people. Common side effects are itching and mild digestive problems such as heartburn, diarrhea, vomiting, and nausea. Other side effects include fatigue, headache, difficulty sleeping, sun sensitivity, and nail changes. People with liver disease should avoid glucosamine if possible. People who have a shellfish allergy and take glucosamine extracted from shellfish may have an allergic reaction.
No drug interactions have been proven.
More Information about Glucosamine
The following is an English-language resource that may be useful. Please note that THE MANUAL is not responsible for the content of this resource.
National Institutes of Health (NIH), National Center for Complementary and Integrative Health: Information on the use of glucosamine and chondroitin for osteoarthritis
