Glucosamine and chondroitin, two popular supplements used to treat joint pain, simply don't work, a new study concludes.

European researchers analyzed the results of 10 previous studies involving more than 3,800 osteoarthritis patients. They assessed changes in levels of pain after patients took glucosamine, chondroitin or a placebo to treat arthritis in their hips or knees.

They found neither supplement -- taken either separately or together -- did any better for pain relief than the placebo. Nor did they find any differences in joint space narrowing in the patients.

Glucosamine and chondroitin have been used for years by many with arthritic knee or hip pain, often on the recommendation of their doctors. The supplements are derived from components of human connective tissues found in cartilage and bone. The thinking had been that the supplements strengthen cartilage, thereby reducing joint swelling and pain.

But Peter Juni, head of the Institute of Social and Preventive Medicine at the University of Bern in Switzerland says his study shows no pain relief differences among those taking the pills.

But neither did the team find any proof glucosamine or chondroitin were dangerous.

"We see no harm in having patients continue (taking these supplements) as long as they perceive a benefit and cover the cost of treatment themselves," wrote Juni and colleagues in the journal BMJ.

They added: "Health authorities and health insurers should not cover the costs for these preparations, and new prescriptions to patients who have not received treatment should be discouraged."