Glucosamine sulfate, a dietary supplement, is not more effective than a placebo in relieving pain for patients of osteoarthritis of the hip, according to a study led by Rianna Rozendaal and published in the Annals of Internal Medicine. The randomized two-year study was conducted on 222 people suffering from mild to moderate osteoarthritis of the hip, with half the group partaking 1,500 milligrams of glucosamine daily and the other half taking a placebo. The researchers concluded that the rate of improvement was insignificant between patients receiving glucosamine sulfate and those receiving the placebo. Critics said, however, that the study may have produced different results if it had been conducted for an additional year or if patients with more severe osteoarthritis had been studied.