Page updated Feb 18, 2019.
First published Jul 29, 2013.
Chitosan is a much sought after ingredient in fat burners. Apparently, chitosan causes weight loss by suppressing the absorption of fats present in diet. Notwithstanding its popularity, the evidence in support of the weight-reducing abilities of chitosan is not too cut and dry. Although initial studies did conclude that chitosan works, the more recent view is that there is ‘sufficient doubt’ that chitosan causes weight loss.
Obesity and the associated diseases that spring up from being obese or overweight have been causing havoc to human health. Failure of exercise and dietary interventions in controlling obesity has meant that the use of supplement containing natural ingredients has become an attractive option.
Of the ingredients that fat burners contain, chitosan is much sought after by those looking to lose weight. Notwithstanding its popularity, the evidence in support of the weight-reducing abilities of chitosan is not too cut and dry. Although initial studies did conclude that chitosan works, the more recent view is that there is ‘sufficient doubt’ that chitosan causes weight loss.
Let’s get to the bottom of the affair.
What is Chitosan?
Chitosan is N-deacetylated derivative of the polysaccharide chitin (Zhang, Zhong, Tao, Wu, & Su, 2012).
It is present in nature within the shells of invertebrate crustacean creatures like crabs, lobsters and shrimps (Zhang et al., 2012). Since it is biologically active and lacks toxicity in humans, chitosan makes for a perfect candidate for therapeutic treatment for obesity.
How Does Chitosan Help you Lose Weight?
Although not much is known about how chitosan may be causing fat loss, researchers have suggested some mechanisms:
- Inhibits fat absorption and digestion in the intestine
- Acts synergistically with ascorbic acid (Vitamin C) to further reduce fat digestibility
Kanuachi et al., in their paper published in 1994, have outlined the possible mechanism which may be responsible for reducing fat digestion (Kanauchi, Deuchi, Imasato, Shizukuishi, & Kobayashi, 1995).
- Ingested chitosan gets dissolved in the stomach
- Dissolved chitosan mixed with fat in diet; a chitosan-fat complex is formed
- On entry into the small intestine, this complex form a gel; absorption of fat is therefore inhibited
- Fat in the chitosan get is excreted as such without absorption
What is the Safe Dosage for Chitosan and Does it Cause Any Untoward Effects?
The safety dose for chitosan as a supplement has not been defined. Various researchers have used different daily does for their studies – ranging from 2g to 3.1g (Wuolijoki, Hirvela, & Ylitalo, 1999; Schiller, Barrager, Schauss, & Nichols, 2001; Pittler, Abbot, Harkness, & Ernst, 1999; Ho, Tai, Eng, Tan, & Fok, 2001).
Please beware that most of these doses (2g to 3.1g per day in divided doses) were associated with adverse effects. Supplement containing such doses are, therefore, best avoided.
The reported mild gastrointestinal adverse effects are:
- Abdominal discomfort including the feeling of bloating,
- Flatulence (gases),
- Diarrhoea or constipation,
- Nausea, and
- Heart burn
- Allergic reaction if allergic to shellfish
Some have reported symptoms unrelated to the gastrointestinal tract – like headache and swollen heels or wrists (Wuolijoki et al., 1999). Most frequently observed adverse effects are abdominal bloating, flatulence (gases) and constipation (Pittler & Ernst, 2005).
What Do Researchers Know About Chitosan That We Don’t?
Many of the researchers who investigated chitosan support its fat reducing abilities (Kanauchi et al., 1995; Nauss, Thompson, & Nagyuvary, 1983; Nagyvary et al., 1979; Vahouny, Satchithanandam, Cassidy, Lightfood, & Fzirda, 1983). However, lately several methodological limitations in these studies have been pointed out by others (Ernst & Pittler, 1998).
In addition to the above mentioned studies, Ernst and Pittler for their meta-analysis used 4 double-blind trials. They found;
considerable doubt that chitosan is effective for reducing body weight in humans
Source: (Pittler & Ernst, 2005).
Other scientists feel that the proof in support of chitosan is inconclusive (Pittler & Ernst, 2005; Ni, Dunshea-Mooij, Bennett, & Rodgers, 2005) and more research is needed before we can say for sure if chitosan indeed causes weight loss or no (Zhang et al., 2012).
So, What’s Our Take on Chitosan?
Considering the dicey evidence in favour of chitosan, we suggested you hold on to your money until such time that concrete proof (that chitosan causes weight loss) is unearthed by researchers.
- Ernst, E. & Pittler, M. H. (1998). Chitosan as a treatment for body weight reduction? Perfusion, 11, 461-465.
- Ho, S. C., Tai, E. S., Eng, P. H., Tan, C. E., & Fok, A. C. (2001). In the absence of dietary surveillance, chitosan does not reduce plasma lipids or obesity in hypercholesterolaemic obese Asian subjects. Singapore Med J, 42, 6-10. Online Reference
- Kanauchi, O., Deuchi, K., Imasato, Y., Shizukuishi, M., & Kobayashi, E. (1995). Mechanism for the inhibition of fat digestion by chitosan and for the synergistic effect of ascorbate. Biosci.Biotechnol.Biochem., 59, 786-790.
- Nagyvary, J., Falk, J., Hill, M., Schmidt, M., Wilkins, A., & Bradbury, E. (1979). The hypolipidemic activity of chitosan and other polysaccharides in rats. Nutr Rep Int, 20, 684.
- Nauss, J., Thompson, J., & Nagyuvary, J. (1983). The binding of micellar lipids to chitosan. Lipids, 18, 714-719.
- Ni, M. C., Dunshea-Mooij, C. A., Bennett, D., & Rodgers, A. (2005). Chitosan for overweight or obesity. Cochrane.Database.Syst.Rev, CD003892. Online Reference
- Pittler, M. H., Abbot, N. C., Harkness, E. F., & Ernst, E. (1999). Randomized, double-blind trial of chitosan for body weight reduction. Eur J Clin Nutr., 53, 379-381. Online Reference
- Pittler, M. H. & Ernst, E. (2005). Complementary therapies for reducing body weight: a systematic review. Int J Obes (Lond), 29, 1030-1038. Online Reference
- Schiller, R., Barrager, E., Schauss, A., & Nichols, E. (2001). A randomized, double-blind, placebo-controlled study examining the effects of a rapidly souble chitosan dietary supplement on weight loss and body composition in overweight and mildly obese individuals. JANA, 4, 42-49.
- Vahouny, G., Satchithanandam, S., Cassidy, M., Lightfood, F., & Fzirda, I. (1983). Comparative effects of chitosan and cholestyramine on lymphatic absorption of lipids in the rat. Am J Clin Nutr, 38, 278-284.
- Wuolijoki, E., Hirvela, T., & Ylitalo, P. (1999). Decrease in serum LDL cholesterol with microcrystalline chitosan. Methods Find.Exp.Clin Pharmacol., 21, 357-361. Online Reference
- Zhang, H. L., Zhong, X. B., Tao, Y., Wu, S. H., & Su, Z. Q. (2012). Effects of chitosan and water-soluble chitosan micro- and nanoparticles in obese rats fed a high-fat diet. Int J Nanomedicine., 7, 4069-4076. Online Reference
About the author: Rachel Butler
Rachel has been with us since we launched back in 2012.
Rachel has reviewed countless products over the years, and has written many articles offering sound advice. Her professional opinions are widely respected.
Rachel graduated a BSc in Clinical Science from the University of Leicester, U.K.
She lives in York with her husband and young daughter and their dog, a little terrier named Betsy.
Disclaimer: Our reviews and investigations are based on extensive research from the information publicly available to us and consumers at the time of first publishing the post. Information is based on our personal opinion and whilst we endeavour to ensure information is up-to-date, manufacturers do from time to time change their products and future research may disagree with our findings. If you feel any of the information is inaccurate, please contact us and we will review the information provided.
Have Your Say
1 comment on 'Chitosan – A Success Story or Another Duff Ingredient?'
I have tried various weight loss products at times. Some years ago I took ChitoSlim, then sold by Great American Products. It’s the only thing I’ve taken that produced real results. I lost over 20 pounds in 6 weeks without any diet change. Weight came back after 4 or 5 years, but when I tried to order the ChitoSlim again, it was no longer available. For me, it was the best! I did try another chitosan product, but had an allergic reaction that the doctor said was likely a reaction to shellfish. I don’t know why the ChitoSlim didn’t affect me that way. No, I have no financial interest in Great American Products. I just wish they hadn’t discontinued that product. I was impressed.