What's known about the benefits of glucosamine and chondroitin
Dozens of compounds are marketed as dietary supplements for OA, but by far the most popularand probably the most promisingis glucosamine, which is often taken along with chondroitin sulfate. Both are natural substances found in healthy cartilage and synovial fluid, which cushion joints. Many experts have looked at whether or not taking supplemental doses may slow or prevent deterioration of cartilage and reduce pain and stiffness.
But do they really work? Over the years, research has produced conflicting results. Experts hoped a clear answer would come from GAIT (Glucosamine/chondroitin Arthritis Intervention Trial), a large study of people with OA of the knee. In 2006, results of the study showed that neither glucosamine nor chondroitin, alone or in combination, worked significantly better than placebo in reducing pain or other symptoms when taken for six months. (The prescription pain reliever Celebrex, also tested, fared only slightly better.)
In a 2008 followup study, subjects continued treatment for another 18 months and then had x-ray exams to measure cartilage loss. The exams found only insignificant differences in cartilage loss among the groups.
These disappointing findings are probably not the last word on glucosamine and chondroitin. As in most studies, the scientists called for more research. So, if you take one or both supplements and find it helps, this may be due to the placebo effect, which can be powerful when it comes to pain relief. Talk to your doctor, who may advise you to continue taking the supplement or to stop for a while to see if there's a difference.