What Are Glucosamine and Chondroitin?
Glucosamine and chondroitin are structural components of cartilage, the tissue that cushions the joints. Both are produced naturally in the body. They are also available as dietary supplements. Researchers have studied the effects of these supplements, individually or in combination, on osteoarthritis, a common type of arthritis that destroys cartilage in the joints.
- A large National Institutes of Health (NIH) study, called the Glucosamine/chondroitin Arthritis Intervention Trial (GAIT), compared glucosamine hydrochloride, 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, although the investigators saw evidence of improvement in a small subgroup of patients with moderate-to-severe pain who took glucosamine and chondroitin together.
- In several European studies, 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 large, well-done studies differ. It may be because of 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.