Types of Glucosamine
There are three different types of glucosamine: glucosamine sulfate, glucosamine hydrochloride, and N-acetyl glucosamine. Some researchers believe that glucosamine sulfate may be more effective than the others, as studies suggest that other forms (without the sulfate component) showed little or no benefit. Many people believe that there are significant differences between different types of glucosamine, but more research is needed to confirm these findings.
Glucosamine is a popular dietary supplement usually used for the treatment of osteoarthritis. There are a few different types of glucosamine. Although some people believe there are significant and important differences between these types, it is not yet clear if they are equivalent or if one is better than the others.
Most drugs and many supplements come as a "salt." This is a chemical term meaning that the active ingredient is "stuck" together with an inactive ingredient for various purposes. Sometimes the salt that forms is more stable, better absorbed, or simply less expensive to make. Glucosamine comes in two different salt forms: glucosamine sulfate and glucosamine hydrochloride. The glucosamine is the active ingredient, and the hydrochloride or sulfate is the extra part "stuck" on the glucosamine molecule. When thought of in this manner, there appears to be no reason why either type should be more effective than the other; the active ingredient is still glucosamine.
However, some researchers believe that the sulfate part of glucosamine sulfate might actually be the active ingredient, not the glucosamine, for various reasons. Early studies (which used glucosamine sulfate) showed positive results. Later studies, which used either other forms or combinations of different forms, often showed little or no benefit. In addition, taking glucosamine does not actually increase the level of glucosamine in the blood, leading researchers to suspect that it might be the sulfate part of the molecule that is contributing to the effects.
There is another side to this argument, however. The early studies done with glucosamine sulfate were usually sponsored by one particular patented brand of glucosamine, which might suggest that the studies were somehow flawed by a conflict of interest. Perhaps there is no real difference between the types of glucosamine and the later studies simply suggest that glucosamine (in any form) does not work.
There is one other type of glucosamine, called N-acetyl glucosamine. It is not clear if this type is significantly different from either of the other more commonly used types.