If you're one of the millions of people taking glucosamine to treat arthritis, you may be confused by a few recent findings. Two large-scale studies indicated that this popular supplement is no more useful than placebo in treating the condition characterized by joint pain, inflammation and stiffness.

Glucosamine is a highly common, natural compound. It's made up of glucose and glutamine, an amino acid. It helps to form and repair complex carbohydrates that are part of bone and cartilage. In a degenerative condition such as arthritis, cartilage and bone breaks down and molecules built from glucosamine are lost. The most popular form used to combat arthritis is glucosamine sulphate.

A study recently published in the October 2008 issue of Arthritis & Rheumatism involved patients who were enrolled in an upcoming Glucosamine/chondroitin Arthritis Intervention Trial (GAIT). Researchers wanted to determine if glucosamine could reduce structural damage caused by osteoarthritis.

The results suggested that the supplement had no clinically significant effect on slowing the rate of joint space width loss. However, the results were not definitive. For one thing, the rate of joint degradation was slower than expected, and there was some improvement among participants who had moderate osteoarthritis. This study echoes findings of a previous 2004 study that dampened glucosamine's image as a magic bullet to cure arthritis.

However, researchers have begun to study other compounds based on glucosamine, or glucosamine derivatives. Italian researchers investigated the effects of one derivative called N-acetyl-phenylalanine derivative (NAPA) on osteoarthritis in rats. Results suggested that NAPA can help to repair cartilage and fight inflammation.

North of the border Dr. Tassos Anastassiades, a researcher with the Canadian Arthritis Network, has patented a glucosamine derivative called AnabuTM. It is currently licensed only for treating animals, but steps are underway to have it licensed for human use.

"We've taken the starting material, pure glucosamine, and then chemically modified it," says Dr. Anastassiades in an annual report published by the Networks of Centres of Excellence. "Specifically, the modification is on the nitrogen atom of the sugar. This is the same atom that is naturally modified by humans and other species, before glucosamine becomes part of the structure of the cartilage of joints."

Dr. Anastassiades expects the derivative to have advantages over the parent glucosamine. He points out that glucosamine is metabolized very rapidly, so when you take the over-the-counter form, very little is likely to reach your joints as free glucosamine. Also, in some cases glucosamine (especially at high concentrations) can inhibit cartilage cell growth; this derivative doesn't have those inhibitory effects.

Should You Stop Taking Glucosamine?

While you wait for these new and improved glucosamine derivatives to hit the market, should you give up glucosamine? Despite the conflicting studies on its effectiveness, the answer is probably no. For one thing, it's hard to ignore the anecdotal evidence of the benefits of glucosamine. Also, in some trials it has been effective at slowing joint space width loss and repairing cartilage.

Glucosamine is also a much safer compared to non-steroidal anti-inflammatory drugs (NSAIDs), which have many side effects including nausea, vomiting, diarrhea, constipation, stomach irritation, and dizziness. More serious adverse reactions include ulcers, kidney and liver problems, and excessive bleeding after injury or surgery.

Pregnant or nursing women and children should not use glucosamine. If you have diabetes, speak to your doctor before taking the supplement.