Millions of people take the dietary supplements glucosamine and chondroitin to relieve the pain of osteoarthritis in their knees, hips, and fingers. Some also buy the supplements for their arthritic pets.
But because supplements are only loosely regulated by the Food and Drug Administration, you can’t be sure about the quality of these products. Does your supplement have what it’s supposed and in the right amounts?
To find out about joint supplements, consumerlab.com recently tested 26 popular glucosamine and chondroitin products for people and 6 for pets. (Consumerlab.com is a private company that’s been testing the quality of supplements since 1999.)
The good news is that all 26 products that contained glucosamine or chondroitin or both really did contain these compounds and in the amounts listed on the label. So it looks like your odds are good for picking out a quality brand.
However, your pet may not be so fortunate. Two of the six pet supplements that Consumerlab.com tested did not contain enough glucosamine or chondroitin and a third had too much arsenic!
We can’t tell you which brands were good and which were not. Consumerlab.com supports itself by selling subscriptions to its results. It couldn’t stay in business if people gave away their information for free. And we do want them to continue their work because they’re the only outfit that regularly tests supplements. The government doesn’t do it.
So, is glucosamine and chondroitin worth taking for osteoarthritis?
The answer isn’t clear.
Glucosamine is a compound made by our bodies that helps form cartilage. At least 25 randomized controlled trials over the last three decades haven’t produced a consensus about whether glucosamine pills are more effective than a placebo.
“Glucosamine doesn’t work, period,” says arthritis expert David Felson of the Boston University School of Medicine.
Not so certain is Roland Moskowitz of the University Hospitals Case Medical Center in Cleveland. “There are reasons to think that it may help, and some studies that suggest it does,” he counters. Yet Moskowitz helped run the National Institutes of Health’s GAIT trial, which found that glucosamine doesn’t work.
Two forms of glucosamine
One reason for the uncertainty: there are two forms of glucosamine. Glucosamine hydrochloride–the kind in most supplements and the one used in the GAIT trial—was no better than a placebo in three studies.
Glucosamine sulfate, on the other hand, seems to relieve pain and improve function, according to the Cochrane Collaboration, a network of scientists who review the evidence for medical therapies.
But all nine trials that found a benefit were funded and run by the supplement industry, usually by the Italian manufacturer of one glucosamine sulfate formulation. In the three trials that were conducted by independent investigators, glucosamine sulfate was no better than a placebo.
Despite the lack of evidence, Felson doesn’t talk his patients out of trying glucosamine. “If they think something is working and it’s not dangerous, I don’t discourage its use.”
Our bodies also make chondroitin, which provides some of cartilage’s resistance to pressure. In the more rigorous trials, chondroitin alone didn’t relieve arthritis pain better than a placebo.
A combination of the two?
In the GAIT trial, taking glucosamine hydrochloride plus chondroitin every day for six months didn’t relieve pain or improve joint function any more than a placebo for 317 people with osteoarthritis of the knee. At first, researchers thought that the combination may have helped just the 57 participants who started the trial with moderate-to-severe pain. But when they monitored participants for two more years, they saw no benefit.
Find this article about dietary supplements for arthritis interesting and useful? Nutrition Action Healthletter subscribers regularly get sound, timely information about staying healthy with diet and exercise, delicious recipes, and detailed analyses of the healthy and unhealthy foods in supermarkets and restaurants. If you’re not already subscribing to the world’s most popular nutrition newsletter, click here to join hundreds of thousands of fellow health-minded consumers.