EDMONTON, CANADA. Glucosamine is a natural component of glycosaminoglycans found in cartilage and synovial fluid. Several studies have concluded that glucosamine is effective in the treatment of osteoarthritis of the knee and other areas. In Europe glucosamine is regarded as a medication and is subject to strict quality control. In Canada and the US it is freely available as glucosamine sulfate (GLS) in health food stores.
Researchers at the University of Alberta recently concluded a study aimed at determining the quality of over-
the-counter GLS products available in Canadian health food stores. They obtained samples of 15 products
from different manufacturers and analyzed their content of GLS and the free base glucosamine, which is
believed to be the active ingredient. They observed one immediate problem with the labeling. Many GLS
products did not state whether the 500 mg they contained was 500 mg of GLS or 500 mg of glucosamine,
the active component. This is important, as 500 mg of GLS would contain, at most, 394 mg of glucosamine.
The researchers found that the amount of glucosamine present in the samples varied widely from the
amount stated on the label. Some brands claiming a content of 500 mg of GLS per capsule actually
contained as little as 295 mg and only 2 out of 15 actually contained 500 mg or more of GLS. One brand
had a labeled content of 1500 mg of GLS, but in actual fact contained only 800 mg. Generally, the products
contained only around 50-60% of the stated amount of GLS. The researchers recommend that the exact
amount of free glucosamine present in the tablets or capsules be stated on the label.