The effect of the dietary supplement, Chitosan, on body weight: a randomised controlled trial in 250 overweight and obese adults

Int J Obes Relat Metab Disord. 2004 Sep;28(9):1149-56. doi: 10.1038/sj.ijo.0802693.


Context: Chitosan, a deacetylated chitin, is a widely available dietary supplement purported to decrease body weight and serum lipids through gastrointestinal fat binding. Although evaluated in a number of trials, its efficacy remains in dispute.

Objective: To evaluate the efficacy of chitosan for weight loss in overweight and obese adults.

Design and setting: A 24-week randomised, double-blind, placebo-controlled trial, conducted at the University of Auckland between November 2001 and December 2002.

Participants: A total of 250 participants (82% women; mean (s.d.) body mass index, 35.5 (5.1) kg/m(2); mean age, 48 (12) y)

Interventions: Participants were randomly assigned to receive 3 g chitosan/day (n=125) or placebo (n=125). All participants received standardised dietary and lifestyle advice for weight loss. Adherence was monitored by capsule counts.

Main outcome measures: The primary outcome measure was change in body weight. Secondary outcomes included changes in body mass index, waist circumference, body fat percentage, blood pressure, serum lipids, plasma glucose, fat-soluble vitamins, faecal fat, and health-related quality of life.

Results: In an intention-to-treat analysis with the last observation carried forward, the chitosan group lost more body weight than the placebo group (mean (s.e.), -0.4 (0.2) kg (0.4% loss) vs +0.2 (0.2) kg (0.2% gain), P=0.03) during the 24-week intervention, but effects were small. Similar small changes occurred in circulating total and LDL cholesterol, and glucose (P<0.01). There were no significant differences between groups for any of the other measured outcomes.

Conclusion: In this 24-week trial, chitosan treatment did not result in a clinically significant loss of body weight compared with placebo.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Anti-Obesity Agents / therapeutic use*
  • Anticholesteremic Agents / therapeutic use
  • Chitin / analogs & derivatives*
  • Chitin / therapeutic use*
  • Chitosan
  • Cholesterol / blood
  • Dietary Supplements*
  • Double-Blind Method
  • Female
  • Humans
  • Male
  • Middle Aged
  • Obesity / blood
  • Obesity / drug therapy*
  • Obesity / physiopathology
  • Treatment Outcome
  • Weight Loss / drug effects


  • Anti-Obesity Agents
  • Anticholesteremic Agents
  • Chitin
  • Chitosan
  • Cholesterol