How much is known about glucosamine supplements?
There is a lot of information about the safety and usefulness of glucosamine from large, high-quality clinical studies in people.
What do we know about the safety of glucosamine supplements?
Clinical studies have found that glucosamine supplements may interact with the anticoagulant (blood-thinning) drug warfarin (Coumadin). Overall, studies have not shown any other serious side effects.
If you take glucosamine supplements, tell your health care providers. They can do a better job caring for you if they know what dietary supplements you use.
What is Glucosamine?
Glucosamine is a component of cartilage. It is produced naturally in the body. Glucosamine is also available as dietary supplements. Clinical studies have looked at the effects of supplements on arthritis.
Cartilage is the connective tissue cushioning bones within the joints. The layer of cartilage between the bones of a joint wears down in osteoarthritis. This causes bones to rub together, which causes pain and swelling and makes it difficult to move the joint.
The knees, hips, spine, and hands are the parts of the body most likely to be affected by osteoarthritis.
What the Science Says About Glucosamine
National Institutes of Health (NIH) study called the Glucosamine/chondroitin Arthritis Intervention Trial (GAIT) compared glucosamine, chondroitin, both supplements together, celecoxib (a prescription drug used to manage osteoarthritis pain), or a placebo (an inactive substance) in patients with knee osteoarthritis.
Most participants in the study had mild knee pain. Those who received the prescription drug had better short-term pain relief (at 6 months) than those who received a placebo.
Overall, those who received the supplements had no significant improvement in knee pain or function. Investigators saw evidence of improvement in a small subgroup of patients with moderate-to-severe pain who took glucosamine.
European studies show participants reported that their knees felt and functioned better after taking glucosamine. The study participants took a large, once-a-day dose of a preparation of glucosamine sulfate sold as a prescription drug in Europe.
Researchers don’t know why the results of these studies differ. Differences in the types of glucosamine used (glucosamine hydrochloride in the NIH study vs. glucosamine sulfate in the European studies), differences in the way they were administered (one large daily dose in the European studies vs. three smaller ones in the NIH study), other differences in the way the studies were done, or chance.
For more information about osteoarthritis, visit the National Institute of Arthritis and Musculoskeletal and Skin Diseases Web site at www.niams.nih.gov. For more information on complementary health approaches for osteoarthritis, see the National Center for Complementary and Integrative Health (NCCIH) fact sheet Osteoarthritis and Complementary Health Approaches.