The belief is the supplements alleviate pain by helping build cartilage, but an examination of 10 clinical trials found glucosamine and chondroitin did not have any clinical effect on osteoarthritis of the hip or knee.
Still, some patients are convinced the supplements help relive their pain.
Researchers say there is no harm in taking the pills, and they suspect any perceived effect has to do with the natural fluctuating course of arthritis or the placebo effects.
They also say insurers should no longer cover the cost of the pills and that new prescriptions of the products should be discouraged.
