The Glucosamine / Chondroitin Arthritis Intervention Trial (GAIT), a large, randomized, double-blinded, placebo-controlled, multicenter clinical trial studied use of glucosamine (500 mg orally 3 times a day), chondroitin sulfate (400 mg orally 3 times a day), and both drugs to treat osteoarthritis of the knee; in the group as a whole, pain was not reduced.