Arthritis sufferers worldwide spend more than $2 billion a year on glucosamine, and more than 1 in 10 US adults use the supplement. But the latest clinical trial of glucosamine has once again failed to find evidence that it does any good.
In results published in Arthritis & Rheumatology, researchers tested 1,500 milligrams of glucosamine hydrochloride, administered daily dissolved in a beverage, against a placebo. The six-month randomized trial involved 201 volunteers, average age 52, with chronic knee pain typical of osteoarthritis. Unlike most previous glucosamine research, which used radiographs to monitor structural changes in cartilage, the study employed more sensitive MRI scans. It found no significant difference in cartilage deterioration between the glucosamine and placebo groups.
This has been a contentious issue, with some positive tests by manufacturers, while trials by independent investigators have largely been negative, comments Timothy E. McAlindon, MD, MPH, chief of the Division of Rheumatology and professor at Tufts School of Medicine. Independent tests of glucosamine hydrochloride show that it definitely does not work. The chief manufacturer of glucosamine in Europe, however, claims its product is different in some way and cites positive studies, so this is not the end of the story.
SEEKING KNEE RELIEF: In addition to analyzing cartilage, C. Kent Kwoh, MD, of the University of Arizona, and colleagues also compared bone-marrow lesions below the cartilage (subchondral). Those assigned to the glucosamine were no more likely to show improvements than participants getting a placebo instead.
A secondary measurement in the study looked at urinary excretion of a type of collagen that is a marker for cartilage deterioration. Again, no statistically significant difference was found, although those not taking the glucosamine actually scored slightly better.
The disappointing findings echo those of a National Institutes of Health-sponsored clinical trial that similarly found little benefit from glucosamine supplements.
If glucosamine is working for you, perhaps because of a placebo effect, Tufts Dr. McAlindon doesnt advocate discontinuing it. Theres no evidence that its hurting anybody, except in the wallet, he explains. If it enables you to cope better and rely less on conventional pharmaceuticals, which do have side effects, theres no downside.