Is Glucosamine Safe for Me?
I am 71 years old, and I have type 2 diabetes. Last year I developed joint problems in both shoulders. Doctors have prescribed physical therapy, which has helped some but not very much. The supplement glucosamine has helped several people I know who have similar shoulder problems. However, these people don't have diabetes. I want to try the supplement, but I have read that glucosamine may contribute to insulin resistance. Elwin Beck, Rio Vista, California
Craig Williams, PharmD, responds: Glucosamine is definitely safe to try. While there are anecdotal reports of patients with diabetes experiencing slight elevations
in blood glucose with either glucosamine hydrochloride or glucosamine sulfate, in the few human studies that have been carefully done, no effect can be detected. These studies are often based on glycated hemoglobin (hemoglobin with glucose attached to it—not a direct measure of glucose levels), and the studies pool the results from many patients, so it is always possible that some individual patients may experience slight changes in blood glucose. Monitoring would obviously be prudent. But again, we consider it safe to try in patients with diabetes.
However, glucosamine being safe doesn't mean that it's effective. Controlled clinical trials have not found a significant positive effect, but some individual patients do seem to experience a benefit. Glucosamine is important for the repair and maintenance of healthy cartilage in joints, but taking it in an oral form may not get it to where it needs to be in an amount that will do any real good. Much of it is broken down in the stomach and digestive tract. Even short trials where similar compounds are injected directly into arthritic joints have not found a significant benefit, and a large study published in the New England Journal of Medicine in 2006 did not find a benefit of orally administered glucosamine plus chondroitin sulfate in patients with painful knee osteoarthritis.
That being said, I have had patients who felt strongly that they benefited from therapy. As long as it is not used in place of physical therapy and appropriate rehabilitation and strengthening exercises, glucosamine may be able to play a role for some patients in helping them to manage their pain. Other agents that we use for pain control have their own side effects, and being able to use less of those medications is often a good outcome all by itself. If you do start glucosamine or chondroitin, make sure to keep your primary health care provider in the loop and remember, too, that they are both considered nutritional supplements, not medications, and therefore are not evaluated and approved by the U.S. Food and Drug Administration.