The ultimate science based guide to taking chitosan for weight loss

Written by , Published: Updated: September 24, 2017

If you're wondering whether or not taking chitosan for weight loss is a good idea, then you've come to the perfect place.

Read my science based guide all the way though, and by the time you're done, you'll know exactly how well you can expect chitosan to work.

What is chitosan and how effective is it for weight loss?

As you'll see, quite a lot of research has already been done on whether or not chitosan actually works for weight loss.

The problem is, many different studies have gotten completely different results. But don't worry, all of this will make perfect sense in a bit.

Before we get started, take a look at this short overview of everything that I've covered in this guide:

Scientific proof that chitosan helps you lose 11 lbs / 5 kg in 4 weeks

By far the most promising study[1] I was able to find on chitosan and weight loss has "proven" it's possible to lose as much as 10,92 pounds (4.95 kilograms) in just 4 weeks.

That's a pretty awesome weight loss boost by any standard, but there is a catch.

(There always seems to be one, when things look a little too good to be true.)

The #1 problem with this study is that they didn't just use chitosan, but some other things (guar, ascorbic acid, and other micronutrients) that could have also helped people lose more weight. Also, the scientists didn't say how much chitosan they used in the study.

In other words, while the weight loss results in the study were pretty awesome, we can't know for sure if chitosan actually had anything to do with them.

Let's take a look at some more science on chitosan and weight loss.

Scientific proof that chitosan DOES NOT WORK for weight loss

Here's another study[2] that didn't really care all that much about weight loss. The scientists actually looked into whether or not chitosan can help bring down the levels of bad cholesterol in your blood.

And while chitosan actually did help bring down the cholesterol levels for the people in the study, it unfortunately had absolutely no effect on weight loss.

That's even after people took chitosan every single day for 8 weeks.

So, yes, even science can be quite confusing sometimes. Because, depending on the study you go by, taking chitosan for weight loss could be a really smart or a really dumb idea.

It's time to end this confusion with more science.

The final verdict on taking chitosan for weight loss

Here's a scientific review [3] of 14 different studies that all looked into chitosan and weight loss.

This review didn't just take a look at the final results of the studies, but also at the quality of the studies. Ultimately, they separated the 14 studies into 4 high quality studies and 10 low quality ones.

(A high quality study means that scientists only used chitosan, that they measured how much chitosan people took, that people were selected 100% randomly, that the conditions were the same for all groups of people, that people were closely monitored not to eat outside their food plans...)

The 10 low quality studies, whose results need to be taken with a grain of salt, showed that chitosan can help people lose 5.1 pounds (2.3 kilograms) on average.

But the 4 high quality studies have only shown chitosan can only help you lose 1.3 pounds (0.6 kilograms) over 4 weeks or more.

So, if you trust the high quality scientific research (and you should), chitosan can only deliver a very small weight loss boost.

But there's one more weight loss benefit of chitosan we need to look at, before we can wrap this up.

Fat-absorption blocking as another weight loss benefit of chitosan

The most intriguing weight loss benefit of chitosan I ever stumbled upon, was definitely a claim that chitosan can block the absorption of fats.

In other words, you can get away with eating lots of fat-calories, if only you take a chitosan supplement with your meals.

How many calories could you actually eat without gaining any extra body fat?

The biggest number I could find[4], was that chitosan can block up to 120 grams of fat per day.

Each gram of fat you eat contains 9 calories. So, if you could use chitosan to block the absorption of 120 grams of fat per day, you could get away with eating as much as 1080 extra fat-calories every day.

The idea of being able to eat that much extra junk every day (without gaining an ounce of weight) sure looks awesome on paper.

But let's turn to science to see if this actually works.

Can chitosan block the absorption of up to 120 grams of fat per day?

I found a study[4] that gives us the perfect answer to this question.

The scientists analyzed the feces of people who were all on the same high-fat diet. The people took chitosan for a few days, but then stopped taking it for the rest of the study.

The idea was, if chitosan actually worked, the feces would contain more fat on the days when people took chitosan. If less fat would be absorbed by the body when taking chitosan, then more of it would be found in the feces.

What happened?

Sadly, nothing.

When people took a chitosan supplement, their feces contained exactly as much fat as when they didn't take it.

In other words, not only did chitosan fail to live up to the claim of being able to block 120 grams of fat per day, it couldn't block ANY fat from absorbing.

Actionable summary

As you saw, lots of science has already been done on whether or not chitosan works for weight loss

The problem is, different studies have come to completely different results:

On average, high quality research has shown that chitosan can only help you lose up to 1.3 pounds (0.6 kilograms) over 4 weeks or more.

If, in spite this scientific confusion about how well chitosan works for weight loss, you still decide to take it, you'll probably do yourself a favor if you don't expect any miracles from it.


1. Colombo P, Sciatto AM. Nutritional aspects of chitosan employment in hypocaloric diet. Acta Toxicol Ther 1996;16:287-302.

2. Bokura H, Kobayashi S. Chitosan decreases total cholesterol in women: a randomized, double-blind, placebo-controlled trial. Eur J Clin Nutr 2003;57:721-725.

3. 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.

4. 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.

Rok Sprogar

Hi, I'm Rok Sprogar.

I'm the guy who singlehandedly turned into a widely popular weight loss blog that gets visited by tens of thousands of people every month.

I reached this level of popularity because I invested thousands of hours into translating complicated science into highly actionable weight loss tips that ANYONE can start using in their lives right away.