The LEGS Study: Do Glucosamine and Chondroitin Show Promise for Pain?


Glucosamine and chondroitin are substances produced naturally by the body that support the generation and lubrication of cartilage. The effectiveness of supplementing with glucosamine and chondroitin sulfates for joint conditions has been tested in many clinical studies. One of the most recent was the Long-term Evaluation of Glucosamine Sulfate (LEGS) study.

What is LEGS?

Consisting of a two-year trial that followed 502 participants ages 45 to 75 years, the LEGS study was designed to determine the effectiveness of supplemental glucosamine and chondroitin on joint space narrowing (JSN) and knee pain in osteoarthritis patients. Participants were divided into four groups and given daily doses of:

  • 1500 milligrams glucosamine sulfate
  • 800 milligrams chondroitin sulfate
  • Both supplements together
  • Matching placebo capsules

Each group kept seven-day diaries to report their knee pain on a scale of one to ten. Knee X-rays were taken three times a year over the course of the study to track changes.

Clinical Results

According to the study abstract, the group taking the combination of glucosamine and chondroitin experienced “statistically significant reduction of 2-year JSN compared to placebo.” This 0.1-millimeter decrease was about half of what the placebo group showed. All groups reported some decrease in knee pain, but “no significant between-group differences” were recorded. Results were adjusted for gender, body mass index, the initial severity of the disease and other “factors associated with structural disease progression.”

An editorial letter printed in the Eular Journal after the release of the LEGS study results noted that there were no apparent “restrictions regarding comedications” among participants, nor was there adjustment made for whether or not glucosamine or chondroitin supplements had been taken immediately prior to the study. The author of the letter also made the point that self-reported pain is a relative measure that varies from person to person. These factors could have had an effect on the LEGS results, although it’s not clear to what extent the accuracy may have been compromised.

Conclusions and Treatments

According to the LEGS study, taking either glucosamine sulfate or chondroitin sulfate alone to treat joint deterioration and knee pain associated with osteoarthritis is ineffective. However, taking both supplements in combination may produce a significant reduction in joint space narrowing over time. A longer study would be required to determine if positive effects continued beyond two years.

Both glucosamine sulfate and chondroitin sulfate are considered safe for long-term use. When compared to NSAIDs, these supplements may be safer since they don’t produce the same side effects, namely the potential gastrointestinal damage associated with prolonged NSAID use. A lower risk of interactions with other medications may make these supplements a better choice for older patients.

As of 2012, the American College of Rheumatology didn’t recommend glucosamine and chondroitin sulfate supplements for osteoarthritis treatment. It’s unclear whether these recommendations will be updated in light of the LEGS study results. As with any supplementation, osteoarthritis patients considering glucosamine and chondroitin for the treatment of their conditions should speak with a physician before beginning a regimen.