Hey, and welcome to my science-based guide to taking chitosan for weight loss.

If you're not sure whether you should be taking chitosan, what kind of weight loss results you can expect and the optimal dosage of chitosan you should take for weight loss, then I've got you covered.

(You'll also find out if chitosan actually works as a fat blocker.)

And as you'll see, the results of different chitosan studies can come across as slightly confusing, but everything will make sense once you read this guide all the way through.

Before we dive in, here's a short overview of everything I've covered in this guide (use it for quick navigation):

Benefits for weight loss

One of the most commonly known weight loss benefits of chitosan is fat blocking.

This happens because chitosan binds itself to the fats you eat (this happens in your colon).

This makes it impossible for your body to absorb those chitosan-bound fats.

So, in theory, chitosan should prevent at least some of the fats you've eaten from ending up as body fat.

And when they tested this theory on animals[1][2], it actually worked pretty well.

But the real question is, did chitosan actually work as a fat blocker in human studies?

Is chitosan a fat blocker?

To answer this, scientist did a study[3] that delivered some surprising results.

You see, if chitosan is a fat blocker, then your feces should contain more (unabsorbed) fat if you took chitosan with your meals.

And that's exactly what the scientists looked at.

They fed people the exact same high-fat meals, first with, then without chitosan.

Then they measured if there was any difference between fats in the feces.

Sadly, the feces contained exactly as much fat when people took chitosan as when they didn't.

So even tough chitosan has been proven to act as a fat blocker on animals, human studies have been disappointing.

But read on, science hasn't given up on chitosan's weight loss potential yet.

Does chitosan work for weight loss?

The short answer is yes.

Science[4] has proven that chitosan does indeed work for weight loss.

So even though chitosan may not work as a fat blocker for humans, there seem to be other forces at play.

Another scientific review[5] combed through 14 different studies on chitosan and weight loss.

And yes, chitosan has been proven to work for weight loss in most of those studies.

(Not in all of them, but we'll get to that in a bit.)

Now, let's get on with answering the burning question on your mind.

What kind of weight loss results can you actually expect from chitosan?

Weight loss results

Unfortunately, this is where things start to get a little tricky.

You see, even though plenty of studies have been done, the weight loss results of chitosan are all over the place.

One scientific review[4] of 5 studies has shown that chitosan can help you lose 7.2 lbs / 3.3 kg in 4 weeks.

(That's 7.23 lbs / 3.28 kg on average, for some people it was even more than that.)

And if chitosan could actually deliver such weight loss results, that would be awesome by any standard.

But like I said, there is more to the story.

You see, the (newer) scientific review[5] of 14 studies showed that chitosan can "only" help you lose 3.74 lbs / 1.7 kg in 4 weeks.

In terms of effort versus weight loss results, that's still ok.

But what gives? Why are there such differences between studies?

Quality of research

To understand why studies came up with completely different weight loss results, you need to understand the differences in quality of chitosan weight loss research.

High-quality research, for example, means that scientists only used chitosan and absolutely no other supplements.

It also means that the people for the studies were selected 100% randomly, that the conditions were 100% the same for all people, that people were closely monitored not to eat outside their food plans, etc.

So when they graded the 14 studies in that scientific review[5], only 4 studies were high-quality.

And those 4 high-quality studies have only shown chitosan can only help you lose 1.3 pounds (0.6 kilograms) over 4 weeks.

So, if you trust the high-quality research into chitosan and weight loss (and you should), then it's clear that chitosan can only deliver small weight loss results.

Optimal dosage

One last thing we have to take a look at.

What is the optimal dosage when taking chitosan for weight loss?

In most of the studies[6][7][8], the scientists gave people 1 gram (1,000 mg) of chitosan per day.

Capsules or tablets were used, and 250 mg of chitosan was taken with 4 different meals of the day.

Based on the amounts used in scientific studies, the optimal dosage of chitosan for weight loss is 1,000 mg, taken four times a day (a 250mg tablet or capsule).

Summary (actionable takeaways)

As you saw, plenty of scientific research has already been done on taking chitosan for weight loss.

One of the most widely known benefit of chitosan is that it acts as a fat blocker.

(The problem is, chitosan has only been proven to work as a fat blocker in animal studies).

And while some studies have shown that chitosan can help you lose 7.2 lbs / 3.3 kg in 4 weeks, you'd do well to consider the quality of chitosan weight loss research as well.

If you only trust the high-quality studies (and you should), then chitosan can only help you lose 1.3 pounds (0.6 kilograms) over 4 weeks.

Which is still nice, but not exactly something to write home about.

If you still decide to start taking chitosan, then you should take it for times a day (4 x 250mg tablet or capsule).


1. Zacour AC, Silva ME, Cecon PR, Bambirra EA, Vieira EC. Effect of dietary chiton on cholesterol absorption and metabolism in rats. J Nutr Sci Vitaminol 1992;38:609–613.

2. Deuchi K, Kanauchi O, Imasato Y, Kobayashi E. Effect of the viscosity or deacetylation degree of chitosan on fecal fat excreted from rats fed on a high fat diet. Biosci Biotechnol Biochem 1995;59:781–785.

3. Gades MD, Stern JS. Chitosan supplementation does not affect fat absorption in healthy males fed a high-fat diet, a pilot study. Int J Obes Relat Metab Disord 2002;26:119-122.

4. Ernst E, Pittler MH. Chitosan as a treatment for body weight reduction? A meta-analysis. Perfusion 1998;11:461–465.

5. Mhurchu CN, Dunshea-Mooij C, Bennett D, and Rodgers A. Effect of chitosan on weight loss in overweight and obese individuals: a systematic review of randomized controlled trials. Obes Rev 2005;6:35-42.

6. Ho SC, Tai ES, Eng PHK, Tan CE, Fok ACK. In the absence of dietary surveillance, Chitosan does not reduce plasma lipids or obesity in hypercholesterolaemic obese Asian subjects. Singapore Med J 2001;42:6–10.

7. Ni Mhurchu C, Poppitt SD, McGill A, Leahy F, Bennett DA, Lin RB, Ormrod D, Ward L, Strik C, Rodgers A, on behalf of the ECHO Collaboration. The effect of the dietary supplement, chitosan, on body weight: a randomised controlled trial in 250 overweight and obese adults. Int J Obes 2004;28:1149–1156.

8. Pittler MH, Abbot NC, Harkness EF, Ernst E. Randomized, double-blind trial of chitosan for body weight reduction. Eur J Clin Nutr 1999;53:379–381.

Written by

Rok Sprogar is a NASM Certified Nutrition Coach (NASM-CNC) and a NASM Certified Weight Loss Specialist (NASM-WLS) who has been contributing highly actionable and science-based content to Leanhigh.