Osteoarthritis, the most common form of joint disease according to PubMed Health, affects nearly everyone by age 70, causing pain, stiffness and mobility loss. A painful wear and tear disorder that breaks down the cartilage that cushions your joints and keeps bones from rubbing together, osteoarthritis often affects the knees, hips, fingers and other joints. Glucosamine, an amino sugar made from shellfish shells, is often taken as a supplement to decrease pain by repairing and preventing breakdown of cartilage, although study results on its effectiveness have been mixed.
Administration
Glucosamine, sold as an over-the counter supplement in the United States, can be taken in a variety of ways, from pills to injections to topical creams. The injection can be given intramuscularly or directly into a joint. Doses of between 400 and 1,000 mg are given orally once or twice per day, with 1,500 mg per day being the most commonly used dose in research studies, according to the Arthritis and Glucosamine Information Center. Glucosamine comes in several forms, including glucosamine hydrochloride and glucosamine sulfate; no one form seems more effective than the others, Stephen Barrett, M.D. states on Quackwatch.
Actions
The benefit of glucosamine is that it repairs the damaged cartilage in the joint by stimulating production of proteins that build cartilage. Repairing the cartilage reduces the risk of bone spur formation within the joint and decreases the pain and joint swelling often associated with osteoarthritis.
Study Results
Study results on the benefits of glucosamine have failed to establish a conclusive positive benefit. A Cochrane review of studies found that glucosamine improved pain in well-done studies, but that function improved in some high-quality studies but not others. A Dutch study published in the February 2008 issue of "Annals of Internal Medicine" reported on the use of 1,500 mg of glucosamine daily for a two-year period to treat arthritis in the hip. No benefit over placebo was seen either in reduction of symptoms or improvement of function at the end of the study.
Safety
Typical side effects of glucosamine include stomach discomfort, intestinal gas, diarrhea, fatigue, dizziness, headache and mood changes. If you have a shellfish allergy, ask your doctor before taking this supplement, since it's made from shellfish shells. Because glucosamine is marketed as a dietary supplement in the U.S. rather than a drug, it undergoes less stringent testing. Amounts of glucosamine and purity may vary from company to company. In 2001, glucosamine manufactured by Vital Nutrients was recalled due to contamination with aristolochic acid, which can cause kidney damage and cancer. Glucosamine may also increase the risk of bleeding if you take blood thinning drugs. In 2008, several people taking the supplement died of liver failure shortly after taking glucosamine, although glucosamine wasn't established as the definite cause, Scottish doctors issued warnings about using it.
References
- The Cochrane Collaboration; Glucosamine Therapy for Treating Osteoarthritis; T. Towheed, et al.; November 2008
- The Arthritis and Glucosamine Information Center; Glucosamine for Osteoarthritis - Bogus or Cure?; S. Phoon, et al.
- Quackwatch; Glucosamine and Chondroitin for Arthritis: Benefit is Unlikely; Stephen Barrett, M.D.; July 2010
- "Annals of Internal Medicine"; Effect of Glucosamine Sulfate on Hip Osteoarthritis; R. Rozendaal, et al.; February 2008
- Science Based Medicine; Glucosamine Update: A New Study and a New Product; Harriet Hall
