If you're taking glucosamine sulfate to treat arthritis in your hip, save your money. It doesn't work, according to researchers writing in the February 19 issue of the Annals of Internal Medicine.

People in middle to old age have long taken the dietary supplement in the belief it would ease pain and inflammation in joints. Dr. Rianne M. Rozendaal at the Erasmus Medical Center in Rotterdam, the Netherlands, headed the research team that concluded the supplement was mostly ineffective as a means to treat hip pain.

The study followed more than 200 patients for two years. All were suffering osteoarthritis of the hip. Half the people in the study took 1,500 milligrames of Glucosamine once a day, the others took placebo.

The researchers said glucosamine sulfate had no apparent effect on hip arthritis. Those with very mild arthritis noted some slight improvement when taking the glucosamine, but the improvement was very small.

"The differences between the glucosamine and placebo group were all very small. For these patients with hip osteoarthritis, glucosaminei sulfate does not seem to be an effective treatment on the basis of our results," the authors wrote.

Glucosamine is a natural compound that is found in healthy cartilage. Glucosamine sulfate is a normal constituent of glycoaminoglycans in cartilage matrix and synovial fluid, according to the Mayo Clinic.

Writing before the current research was public, cllinic scientists said available evidence from randomized controlled trials supports the use of the supplement in the treatment of osteoarthritis, particularly of the knee. Doctors widely prescribe it for patients hoping to slow or prevent cartilage loss.

The new research did not address glucosamine sulfate's effectiveness in any joint other than the hip.

Twenty percent of the U.S. population has been diagnosed with arthritis, according to the Centers for Disease Control, and that number is expected to rise as the Baby Boomers enter old age.