Glucosamine (C6H14NO5) is a dietary supplement distributed as a salt -- commonly, but not limited to, glucosamine HCl, glucosamine sulfate potassium, and glucosamine sulfate sodium. Common dosages of glucosamine are 1,500 mg per day. The salt (e.g. glucosamine sulfate * KCL, glucosamine sulfate * NACL) forms are necessary to stabilize the glucosamine sulfate, whereas glucosamine HCl is stable without requiring a salt to be bound to it.

GoldBamboo

... Glucosamine is available in several different forms that are usually called “salts”. Most of the clinical studies investigating glucosamine’s medical effects have used a salt known as glucosamine sulfate, but other salts such as glucosamine hydrochloride and n-acetyl glucosamine are also sold widely. While all the salts of glucosamine contain the same general components, they may not all produce the same effects in the body. No studies have compared them, so not enough information is available about potential differences in their activity to know whether they are interchangeable. ...
Drug Digest - more...

Chemical structure of α-D-glucosamine Glucosamine (C6H14NO5) is an am ...
Wikipedia - [full article]

Resources