Yucca root, mangosteen juice and fish oil supplements are often touted as remedies for joint pain, but although some lab studies indicate they might help fight inflammation, there's no solid evidence that any of them relieve arthritis in people.
Methylsulfonylmethane (MSM) and S-adenosylmethionine (SAMe) are marketed for joint pain from osteoarthritis, arthritis caused by degeneration of cartilage. Some studies suggest they may be comparable to traditional anti-inflammatory and pain-relieving drugs at reducing pain, but the number of studies is small.
Avocado-soybean unsaponifiables, a mix of avocado and soybean oil extract known as ASU, is less popular here than in Europe, where several trials suggest it works better than a placebo at reducing joint pain. But the best of these studies have been funded by the supplement's manufacturers, leading some experts to question the findings.
Here in the U.S., two supplements lead the pack in terms of popularity: glucosamine and chondroitin, both natural components of joint tissue. The compounds have been used in Europe and Asia for decades and became popular in the U.S. about 10 years ago. They're among the best selling of all supplements on the market and are also the best studied.
The first study hinting that glucosamine and chondroitin in any form might help relieve the pain of inflamed joints was published in 1969. But that and many other early studies were small, or followed people for only a short time or used supplements of inconsistent type and quality.
More recently, large-scale, well-designed studies have examined the effects of the two supplements together and independently, usually in people with knee osteoarthritis, one of the most common forms of arthritis.
Some results have been promising, but on the whole they've been mixed.
In 2006, researchers at the University of Utah in Salt Lake City published results of the Glucosamine/Chondroitin Arthritis Intervention Trial, a study of more than 1,500 adults with knee osteoarthritis, randomized to take either glucosamine, a form of chondroitin called chondroitin sulfate, both, a prescription anti-inflammatory drug or a placebo daily for six months.
Overall, neither glucosamine nor chondroitin sulfate — taken alone or together — worked much better than the placebo, the researchers found. But among patients with severe pain, the combination of glucosamine plus chondroitin sulfate did appear to reduce pain; 79 percent of those with severe pain experienced relief compared with just over half of those who took the placebo. Overall, the prescription drug provided the most relief — and did so faster than the supplements or placebo.
Last year, Vangsness and colleagues published a review of the most rigorous studies in the journal Arthroscopy. They found that the bulk of studies show that glucosamine and chondroitin sulfate do reduce knee osteoarthritis pain when taken together, although results are inconsistent.
Another review, by U.S. and Canadian researchers, was published last year by the Cochrane Collaboration, a nonprofit organization that reviews the science on health topics. Analyzing data from the 25 top studies on glucosamine alone for arthritis, they found that, on average, the supplements result in a 22 percent reduction in pain, but, again, in some studies the supplements worked no better than a placebo.
The Cochrane review included another observation: Glucosamine seemed to work best to reduce knee pain in studies that used a standardized, prescription form of glucosamine sulfate sold in Europe, made by the German company Rottapharm.
The findings on Rottapharm's glucosamine sulfate constitute the best evidence in favor of the compound to date, says study author Dr. Marc Hochberg, professor of medicine and head of the division of rheumatology and clinical immunology at the University of Maryland School of Medicine in Baltimore.
It's not altogether surprising that some supplements would do better than others. In the U.S., supplements are regulated less stringently than prescription drugs. As a result, different brands may contain slightly different amounts or different forms of the promised compound. "It's a problem," Vangsness says. "The source of the chemicals is not standardized."
The problem is complicated by the fact that glucosamine comes in several forms — including glucosamine, glucosamine sulfate and glucosamine hydrochloride — but only glucosamine sulfate has been shown to have the potential to reduce pain.
Doses Used in Most Studies
The daily doses used in most studies are 1,500 milligrams of glucosamine and 1,200 milligrams of chondroitin. Based on existing evidence, taking both appears more likely to reduce joint pain than taking either alone.
What is to Use
But the mixed results have led to a divide among doctors. Vangsness, for example, says he recommends glucosamine sulfate and chondroitin to every one of his arthritis patients, but Hochberg says he doesn't.
If there's one good piece of news for people with arthritis pain, it's this: Side effects of both supplements are rare to nonexistent. So at least they're safe for those who want to give them a try.