Glucosamine Sulphate

Glucosamine sulphate is the most common, and probably the best, supplement form of the biological chemical glucosamine. Glucosamine is made commercially in two ways; one is from enzyme breakdown of shellfish shells, the other is from a fermentation process starting with glucose. Glucosamine, therefore, should not be taken by anyone allergic to shellfish, unless it is the version made from glucose - which is usually labelled "vegetarian". Unfortunately, vegetarian glucosamine is more expensive.
Glucosamine is used because it is an essential part of the formation of proteoglycans, which are found in many places in the body. The main places where glucosamine derivatives are found are in the joints (both in the cartilage itself and in the fluid within the joints) and in the intestinal lining.
Glucosamine is produced by the body for its own purposes. However, glucosamine is often manufactured in large enough amounts, and this is more likely the older you get. If you are not making enough glucosamine, then you are likely to start having problems with your joints, the main one of importance being arthritis. It is also possible for someone who normally does make enough to find that their supply is insufficient; this normally happens after injury to joints.
Glucosamine supplements are common, and the main use for glucosamine is for joint problems. The dosage often recommended for maintenance is 1500mg per day; however, someone who is trying to help their arthritis problem may take perhaps 3000mg per day, and after a specific injury the amount needed may get as high as 15-20,000mg.
Glucosamine is a very safe supplement (as long as you are not shellfish-allergic) and can be taken, even in amounts considerably higher than needed, for very long periods with no ill effects. If you take more than necessary, the body simply shuts down production; and unlike the case with some other supplements, when you stop taking glucosamine your body's production goes back up again.