Mixed Verdict on Glucosamine Supplements
Glucosamine supplements, often taken in combination with chondroitin sulfate, are widely used by people with osteoarthritis. Yet the jury is still out on whether glucosamine really helps. Conflicting results were recently found by two large studies that compared glucosamine to a placebo — a dummy pill that looks like the real thing but doesn’t contain an active ingredient.
Glucosamine from GAIT
Results from the Glucosamine/Chondroitin Arthritis Intervention Trial (GAIT), funded by the National Institutes of Health, were published in the New England Journal of Medicine in 2006. GAIT was the first large-scale, multi-site clinical trial in the United States to test the effectiveness of glucosamine and chondroitin supplements for treating the symptoms of knee osteoarthritis. The 1,583 study participants were randomly assigned to one of five groups: glucosamine alone (1500 mg daily), chondroitin alone (1200 mg daily), both supplements, celecoxib (a prescription medication) or a placebo. To reduce the chance of biased results, the study was double-blinded, which means neither the participants nor the researchers knew which group a particular person was in. All participants also could use acetaminophen (a nonprescription pain reliever) as needed to control their pain during the six-month study.
The study found that glucosamine and chrondroitin, used either alone or in combination, did not reduce pain overall. The results showed that the combination of both supplements might have been effective in a subgroup of participants with moderate to severe pain. But because that subgroup was small, the researchers cautioned that this finding must be considered preliminary.
Glucosamine results from GUIDE
Findings from a second study, called the Glucosamine Unum In Die (Latin for “once a day”) Efficacy (GUIDE) trial, were reported in Arthritis & Rheumatism in 2007. GUIDE was another six-month, multi-site, double-blind study conducted in Spain and Portugal. The 318 participants were randomly assigned to receive either glucosamine (1500 mg daily), acetaminophen or a placebo. Unlike GAIT, this study found that glucosamine was more effective than the placebo at reducing the symptoms of knee osteoarthritis. It’s possible that the discrepancy between the two studies might be due to differences in the supplement formulations. GAIT used glucosamine hydrochloride, while GUIDE used glucosamine sulfate. For now, though, many questions remain about whether glucosamine is helpful for treating osteoarthritis symptoms.
The bottom line
If you decide to try glucosamine anyway, talk to your doctor first to make sure it’s appropriate for you. Also, let your doctor know if you notice any negative reactions after you start the supplement. Since glucosamine is extracted from shellfish, don’t take it if you have a shellfish allergy.
An editorial accompanying the GAIT study (New England Journal of Medicine, February 23, 2006) recommends choosing glucosamine sulfate rather than glucosamine hydrochloride. Consider taking chondroitin sulfate along with it, since there might be added benefits. The editorial suggests giving glucosamine three months to work. If you haven’t seen any improvement by that time, it’s unlikely that taking the supplement for longer will make a difference.
PLEASE NOTE: The studies and their findings that are presented in this article are for informational purposes only and are not meant to take the place of the advice of your doctor. By providing you with this information, Genzyme Corporation is not endorsing its content. You should consult with your doctor before starting any new health regimen.
“Nutritional Supplements for Knee Osteoarthritis — Still No Resolution.” M.C. Hochberg. New England Journal of Medicine. February 23, 2006, vol. 354, no. 8, pp. 858–860.
“Glucosamine, Chondroitin Sulfate, and the Two in Combination for Painful Knee Osteoarthritis.” D.O. Clegg et al. New England Journal of Medicine. February 23, 2006, vol. 354, no. 8, pp. 795–808.
“Glucosamine Sulfate in the Treatment of Knee Osteoarthritis Symptoms: A Randomized, Double-Blind, Placebo-Controlled Study Using Acetaminophen as a Side Comparator.” G. Herrero-Beaumont et al. Arthritis & Rheumatism. February 2007, vol. 56, no. 2, pp. 555–567.
“Questions and Answers: NIH Glucosamine/Chondroitin Arthritis Intervention Trial Primary Study.” National Center for Complementary and Alternative Medicine. Available at: http://nccam.nih.gov/research/results/gait/qa.htm. Accessed September 6, 2011.
“Alternative Treatments for Arthritis: An A to Z Guide.” D. Foltz-Gray. Atlanta, GA: Arthritis Foundation, 2005.
“Dietary Supplements: Background Information.” National Institutes of Health Office of Dietary Supplements. Available at: http://ods.od.nih.gov/factsheets/DietarySupplements.asp. Accessed September 6, 2011.