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.
(See also Overview of Dietary Supplements.)
People take glucosamine mostly to treat osteoarthritis 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.
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.
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