In an osteoarthritis study, 36 older adults with knee osteoarthritis took glucosamine, ibuprofen or a placebo along with performing a leg-strengthening program. After 12 weeks, all participants were stronger. Doctors also measured signs of deteriorating cartilage and found that, compared to the ibuprofen and placebo groups, the glucosamine group had about 15 percent fewer signs of deterioration. In a related study, 28 adults with knee or hip osteoarthritis took 1,500 mg of glucosamine sulfate per day or a placebo for six weeks and then started a 12-week walking program. Those in the glucosamine group had less pain and nearly doubled their physical activity.