Glucosamine is a naturally occurring substance produced by the body, for the purpose of producing glycosaminoglycans and proteoglycans, the key structural components of joint cartilage. Glucosamine is essential for the production, maintenance, and repair of cartilage, the padding at the ends of bones that act as a shock absorber. In osteoarthritis, the body’s ability to manufacture glucosamine is lost, resulting in destruction of cartilage and swollen, stiff, inflamed, and painful joints. Studies suggest that glucosamine supplementation effectively relieves the pain and inflammation of osteoarthritis, and may slow progression of the disease by helping the body repair damaged joints (1-8).
Glucosamine nutritional supplements are available as glucosamine sulfate, glucosamine hydrochloride (HCl), and N-acetyl-glucosamine (NAG). The amount of glucosamine depends on the supplemental form: glucosamine HCL is about 83% glucosamine base, glucosamine sulfate is about 65% glucosamine base, and NAG is about 75% glucosamine base. Studies have shown that both the HCL and sulfate forms are effective with oral absorption rates around 90 percent, although one may be more effective than the other according to individual response (3, 4). However, in vitro studies have shown NAG to be the least effective form (1, 2).
Animal, human, and clinical studies, including double-blind studies, have been conducted with glucosamine sulfate, showing it to be effective in relieving the pain and inflammation of osteoarthritis (1-7). The sulfur component of glucosamine sulfate, which is an essential nutrient for joint cartilage, tendons, and ligaments, may have an important role in the beneficial effects of glucosamine sulfate (1).
Most of the studies on glucosamine HCL have been performed in vitro or on animals, showing it to be effective in relieving the inflammation of osteoarthritis (4,8). However, fewer human and clinical trials are available. One clinical study found that there was no significant difference in pain reduction between glucosamine HCL and a placebo, although it did suggest that glucosamine HCL benefited some patients with knee osteoarthritis (9).
REFERENCES:
1. Murray MT. Encyclopedia of Nutritional Supplements, NY: Three Rivers Press, 1996:336-342.
2. Glucosamine, PDR Health, online:
http://www.pdrhealth.com/drug_info/nmdrugprofiles/nutsupdrugs/glu_0122.shtml
3. Glucosamine Sulfate, The Arthritis & Glucosamine Information Center, online:
http://www.glucosamine-arthritis.org/glucosamine/glucosamine-sulfate.html
4. Owens S et al. Recent advances in glucosamine and chondroitin supplementation. J Knee Surg. 2004 Oct;17(4):185-93.
5. Poolsup N et al. Glucosamine long-term treatment and the progression of knee osteoarthritis: systematic review of randomized controlled trials.
Ann Pharmacother. 2005 Jun;39(6):1080-7. Epub 2005 Apr 26.
6. Pujalte JM, Llavore EP, Ylescupidez FR. Double-blind clinical evaluation of oral glucosamine sulphate in the basic treatment of osteoarthrosis.
Curr Med Res Opin. 1980;7(2):110-14.
7. Noack W, Fischer, M., Forster, KK, et al. Glucosamine sulfate in osteoarthritis of the knee. Osteoarthritis Cartilage. 1994; 2:51-59.
8. Glucosamine: A Review of the Literature, Nutrasense.com, online:
http://www.nutrasense.com/glucosaminelit.html
9. Houpt JB, McMillan R, Wein C, Paget-Dello SD. Effect of glucosamine hydrochloride in the treatment of pain of osteoarthritis of the knee. J Rheumatol. 1999; 26:2423-2430.
