text: Many people with arthritis -- especially osteoarthritis -- use supplements in their diet to ease the pain of arthritis. Glucosamine and chondroitin are the most well-known and best-tested. Methyl sulfonylmethane (MSM) is another supplement used to ease the pain of arthritis, but it has not been through as much rigorous scientific testing.
  There are conflicting studies on glucosamine and chondroitin, some demonstrating a beneficial effect on osteoarthritis pain. Others, including the NIH-sponsored multicenter Glucosamine/Chrondroitin Arthritis Intervention Trial (GAIT), did not show benefit for the primary outcome measure of osteoarthritis pain measured by WOMAC (Western Ontario and McMacster Universities).
  The supplements, which are available in pharmacies and health food stores without a prescription, are well-tolerated and appear to be safe. However, there are no long-term studies to confirm their long-term safety and effectiveness. Many physicians may still recommend a trial of glucosamine at this point, and if there is not apparent improvement by three months, it would be reasonable to stop glucosamine. More definitive conclusions will be made available once the full results are published in the peer-reviewed literature.
  There are many different brands of glucosamine and chondroitin, which are usually sold together in one arthritis supplement. Unfortunately at this time, there is no government monitoring to ensure the purity of these products.
  These arthritis supplements may also have a blood-thinning effect so people taking these supplements in addition to an anticoagulant may have to have their blood tested more often. People who are allergic to shellfish also should consult their doctors before using glucosamine and chondroitin. Glucosamine is extracted from a substance in shellfish.