Chitosan supplementation and fat absorption in men and women

J Am Diet Assoc. 2005 Jan;105(1):72-7. doi: 10.1016/j.jada.2004.10.004.


Objective: Chitosan is a primary ingredient in dietary weight-loss supplements. Its claimed activity is the binding and trapping of dietary fat, leading to fat excretion and weight loss without caloric restriction. We tested the fat-trapping capacity of a chitosan product in men and women.

Design: Participants (12 men, 12 women) were instructed to follow customized diet plans (five meals/day for 12 days). Oral charcoal markers defined two 4-day experimental periods. Two capsules were taken five times per day before each meal during the supplement period (2.5 g chitosan/day) and not during the control period. Feces were collected from day 2 to day 12. Feces from each period were pooled and analyzed for fat content.

Results: For men (mean+/-standard deviation=24.8+/-5.1 years, body mass index [BMI; calculated as kg/m 2 ] 26.6+/-4.5) the average daily was 137+/-31 g fat and 3,256+/-624 kcal. For women (23.3+/-5.0 years, BMI 24.1+/-3.5) average daily 89+/-16 g fat and 2,110+/-195 kcal. Each two-capsule dose was consumed with 28+/-11 g fat in males and 18+/-7 g in females (range =10-76 g/dose). Fecal fat excretion increased with chitosan by 1.8+/-2.4 g/day in males, P =.02, and did not increase with chitosan (0.0+/-1.4 g/day, P =.99) in females.

Conclusions: The fat trapped was clinically insignificant. For men, it would take more than 7 months to lose 1 pound of body fat. For women, no fat was trapped. This product, as with other similar products, fails to meet claims.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Anti-Obesity Agents / administration & dosage
  • Anti-Obesity Agents / pharmacology*
  • Charcoal
  • Chitosan / administration & dosage
  • Chitosan / pharmacology*
  • Dietary Fats / pharmacokinetics*
  • Dietary Supplements
  • Feces / chemistry
  • Female
  • Humans
  • Intestinal Absorption / drug effects*
  • Male
  • Obesity / drug therapy*
  • Obesity / metabolism
  • Sex Factors
  • Treatment Outcome
  • Weight Loss / drug effects


  • Anti-Obesity Agents
  • Dietary Fats
  • Charcoal
  • Chitosan