The market for arthritis drugs is a powerful (46 million people) incentive to sell drug and supplements, and the pain of arthritris is a powerful incentive to take drugs and supplements. Now comes a large and persuasive study, actually a careful analysis of ten other studies involving nearly 4,000 people, that suggests that two of the most popular supplements, glucosamine and chondroitin, do nothing to relieve arthritis pain in knees and hips. Web MD reports that the government-funded Glucosamine/chondroitin Arthritis Intervention Trial (GAIT) showed that overall, the two supplements did not improve hip or knee osteoarthritis (OA) pain. A follow-up arm of this study showed that they did not do any better than placebo in slowing loss of cartilage that occurs in osteoarthritis of the knee. OA is the wear-and-tear form of arthritis, and affects more than 20 million people. WebMD reports that a smaller subset of GAIT participants with moderate-to-severe OA pain, did get some relief with the combined supplements.