Glucosamine, the precursor in the formation of Chondroitin, has been found to stimulate cartilage cells to synthesize glycosaminoglycans and proteoglycansore(1). This essentially means that Glucosamine has the potential to rebuild the cartilage lost in a joint due to injury or osteoarthritis, also known as degenerative joint disease. With more than 30 million Americans suffering from this type of arthritis, it is no wonder that the American College of Rheumatology took a closer look at this supplement. In a 1999 press release they proclaimed that Glucosamine reduces the signs and symptoms of osteoarthritis of the knee. Lead investigator Jean-Yves Reginster, MD, PhD, of the University of Liege in Belgium added that "for the first time, we have shown that a compound may be able at least to slow down the progression of osteoarthritis." They based these findings on a three-year study where they compared disease symptoms and average joint space widths, as measured by X-rays, between patients taking a 1500 mg daily dose of Glucosamine sulfate and those taking a placebo. They found that joint space narrowed in patients taking a placebo, but showed no further narrowing in patients on Glucosamine sulfate. They also found that symptoms worsened for patients taking a placebo and improved for those on Glucosamine sulfate(2). A just released study done over three years demonstrated virtually the same findings(3), further validating the use of Glucosamine for stimulating cartilage growth and joint pain.
Because Glucosamine is a small molecule, it is easily absorbed and very permeable to cell linings. According to the Encyclopedia of Nutritional Supplements, the absorption rate for Chondroitin Sulfate is estimated between 0 and 8 percent. In contrast, studies show up to 98% of the orally administrated Glucosamine Sulfate is absorbed(4). The very recent long-term study demonstrated slightly higher side effects occurring with taking Glucosamine orally(3), while another demonstrated that only 1% of patients taking the Glucosamine had epigastric pain/tenderness, heartburn, diarrhea and nausea(5). Glucosamine can be taken in pill or liquid form, administered though intramuscular injections, and more recently can be found in topical formulas. The effectiveness of a topical formula is dependent on the ability of the ingredients to penetrate the skin barrier. Creams and lotions usually lack this ability to penetrate, as they usually contain thick, non-absorbing, and often waxy ingredients. Glucosamine Sulfate is currently sold over the counter in the United States as a supplement and therefore not currently evaluated by the FDA.