Effect of chitosan on weight loss in overweight and obese individuals: a systematic review of randomized controlled trials

Obes Rev. 2005 Feb;6(1):35-42. doi: 10.1111/j.1467-789X.2005.00158.x.


This article aims to determine whether chitosan, a popular, over-the-counter, weight loss supplement, is an effective treatment for overweight and obesity. It is designed as a systematic review of randomized controlled trials. The data sources include the electronic databases Medline, EMBASE, Biosis, CINAHL and Cochrane Central Register of Controlled Trials (CCTR); the specialized websites Controlled Trials, International Bibliographic Information on Dietary Supplements (IBIDS), System for Information on Grey Literature in Europe (SIGLE), Reuter's Health Service, Natural Alternatives International and Pharmanutrients; and bibliographies of relevant journal articles. Included were randomized controlled trials of chitosan with a minimum duration of 4 weeks in adults who were overweight or obese and/or had hypercholesterolaemia at baseline. Fourteen trials involving a total of 1071 participants were included in the review. Analyses involving all trials indicated that chitosan preparations result in a small but statistically significant greater reduction in body weight (weighted mean difference -1.7 kg; 95% confidence interval -2.1, -1.3 kg, P < 0.00001) compared with placebo. Analyses restricted to high-quality studies showed that reductions in weight [-0.6 (-1.2, 0.1) kg, P = 0.11] were less than in lower quality studies [-2.3 (-2.7, -1.8) kg, P < 0.00001]. Results obtained from high-quality trials indicate that the effect of chitosan on body weight is minimal and unlikely to be of clinical significance.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review
  • Systematic Review

MeSH terms

  • Anti-Obesity Agents / therapeutic use*
  • Chitosan / therapeutic use*
  • Dietary Supplements
  • Humans
  • Meta-Analysis as Topic
  • Obesity / drug therapy*
  • Randomized Controlled Trials as Topic
  • Treatment Outcome
  • Weight Loss


  • Anti-Obesity Agents
  • Chitosan