Chitosan Review
Chitosan is sold as a “fat attractor”, where the user can allegedly lose weight without having to actually eat less. Wikipedia has an extremely thorough analysis of Chitosan, so I’ll let you decide for yourself if it’s an ingredient worth including in a dietary supplement:
The following are conclusions and specific discussion made from researchers, although take note that their specific studies were not given with precise accounts of their experimentation. It is now generally accepted that soluble dietary fibers increase gastrointestinal lumen viscosity (Edwards, 1990) and delay gastric emptying (Chang, 1983). Chitosans have specifically been shown to alter bile acid composition, increase neutral sterol excretion and reduce ileal fat digestibility (Fukada, 1991; Maezaki, 1993; Razdan & Pettersson, 1994). The mechanisms by which chitosans achieve these effects are not fully established, although increased intestinal viscosity and increased bile acid-binding capacity are two proposals currently favored (Furda, 1990). Since polyglucosamines are the second-most-ubiquitous dietary fiber after cellulose, it is reasonable to assume that much more research regarding the nutritional significance of these important dietary fibers is to be expected (Knorr, 1991). Chitosan has such characteristics that are associated with a dietary fiber which are assumed to be related to the reductions in cholesterol as well as increases in the excretion of neutral steroids observed in animal experiments (Furda, 1990; Ikeda, 1993; Razdan & Pettersson, 1994). Chitosan, which is largely deacetylated, contains cationic groups located on the polyglucosamine chain (Sugano, 1993). Thus, chitosan may have a bile acid-binding capacity, causing entrapment or disintegration of mixed micelles in the duodenum and ileum (Furda, 1990). This interruption in bile acid circulation would lead to reduced lipid absorption and increased sterol excretion. Chitosan is relatively insoluble in water but is soluble in dilute acids, giving rise to highly-viscous dietary fibers (Furda, 1990). It has been suggested that viscous dietary fibers such as chitosan inhibit uptake of dietary lipids by increasing the thickness of the intestinal lumen boundary layer, a proposal again supported by numerous animal experiments (Sugano, 1993; Ikeda, 1993).
Admittedly, all of those studies are from the prior decade. According to this study, a group receiving six 500 mg chitosan capsules per day lost 2.8 lb. more than the control group, +/- .8 lb.
But in case you missed it, the treatment group’s chitosan dosage was a total of three grams daily. Also, the study doesn’t mention how long these groups were tested. Approximately three pounds more of weight loss with a dosage that high doesn’t really excite me too much.
According to Quackwatch.org, the FTC had their hands full for a while with companies touting Chitosan-filled products as “reduc[ing] the risk of obesity” or letting you “eat what you want and never, ever, ever have to diet again.”
While Chitosan may have some weight loss benefit at high dosages, I would not rank it as an effective diet pill ingredient.