The supplements, glucosamine and chondroitin, are either taken on their own or in combination to reduce the pain caused by osteoarthritis in the hips and knees.
But in a review of trials involving 3,803 patients with knee or hip osteoarthritis, the Swiss researchers found there was "no clinically relevant effect" of chondroitin, glucosamine, or the two in combination on perceived joint pain.
"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," said Peter Juni of the University of Bern, whose study was published in the British Medical Journal on Friday.
Osteoarthritis is the most common form of arthritis and is one of the leading causes of chronic disability in the United States. It affects about eight million people in Britain and nearly 27 million people in the United States.
It is a chronic condition which is mainly treated with painkillers and anti-inflammatory drugs like aspirin and ibuprofen. Some of these drugs can cause stomach and heart problems, particularly if they used for long periods.
Juni's team said in their study that in the past decade, doctors and specialist rheumatologists have increasingly prescribed glucosamine and chondroitin to their patients, and people with joint pain also buy them over the counter.
According to their research, global sales of glucosamine supplements reached almost $2 billion in 2008 — an increase of about 60 percent since 2003.
The researchers reviewed 10 previously published trials and assessed data on changes in levels of pain after patients took glucosamine, chondroitin, or a combination, compared with a placebo, or dummy pill.
"Compared with placebo, glucosamine, chondroitin, and their combination do not reduce joint pain or have an impact on narrowing of joint space," they wrote.
The scientists noted that despite this finding, some patients remained convinced that the supplements work. They said this may be because of the naturally fluctuating course of osteoarthritis or due to a placebo effect, which can be particularly marked when it comes to pain.
