Chitosan is made from chitin, obtained from the shells of crustaceans such as crabs. First discovered in 1811, the first applications of chitin were for industrial purposes such as water filtering and wine making. Today, however, it is used for a number of medical purposes.
Bandages containing chitosan are used by both the UK and US military, because of its ability to clot blood quickly. It also has antibacterial properties, and as it seals blood vessels it is thought to also block pain messages.
Recently chitosan has been gaining popularity as a weight loss supplement. It is an indigestible substance, and it binds to a small amount of fat during the digestion process, helping to prevent this fat from being absorbed by the body. It may also slow stomach emptying, which helps to keep you feeling full for longer.
It is thought that chitosan may be helpful in controlling and regulating blood sugar, and in lowering cholesterol.
Chitosan has been shown to increase the bioavailability of calcium consumed in the diet, and it has also been investigated as a possible treatment for acne.