Review Fructase: supplement to tolerate fructose

Nowadays there are increasingly more options for people with intolerances that make it possible to eat the products they cannot endure without getting symptoms.

More and more often, there are supplements available which can help your body to digest the products you don’t tolerate well. In this blog I’d like to tell you more about the supplement Fructase from the brand Intoleran, that helps with the digestion of fructose. 

This blog was written in collaboration with Intoleran (formerly called Disolut). This doesn’t change my opinion towards the product. I wrote this review because the supplement works for me, and I think that it can be valuable for you too. 

This blogpost contains affiliate links. Read more about what affiliate links are and why I use them.

What is fructose?

Fructose, also known as fruit sugar, is a monosaccharide (a singular sugar or carbohydrate). It is one of the 4 FODMAP groups, the “M” in FODMAP is for monosaccharide.

Fructose occurs in fruit and is also used as a sweetener in for example candy, biscuits and soft drinks. Most kinds of sugar consist of a combination of fructose and glucose. Regular white sugar for example consists of 50% fructose and 50% glucose. 

What is fructose malabsorption?

In some people, the fructose they eat doesn’t digest well in the small intestine. The remaining fructose goes to the large intestine and feeds the bacteria in the large intestine.

These bacteria ferment the fructose and this leads to symptoms like bloating, stomach aches and diarrhoea or constipation. 

The FODMAP diet describes that the majority of people tolerate food that consists of an even amount of glucose and fructose, or a majority of glucose. When the amount of fructose is higher than the amount of glucose (excess fructose), your body struggles to digest the fructose and you develop symptoms.

This is why high-fructose food belongs to the list of high FODMAPs. Examples of high-fructose food and ingredients are mango, asparagus, honey, fruit juices, fructose (syrup), fructose-glucose syrup and agave syrup. 

disolut lutomerase

Testing your fructose intolerance

You can test your fructose intolerance by testing a high-fructose product in different amounts. In the FODMAP diet, this is usually done with mango or honey.

For example: on day 1 you take a teaspoon of honey, on day 2 you take half a tablespoon of honey, and on day 3 you take a tablespoon of honey.

When you eat strictly low FODMAP on the testing days and your symptoms are stable in general, your reaction to the fructose will tell you if you can or cannot tolerate fructose. 

I tested fructose as well as a part of the reintroduction phase of the FODMAP diet. For me, this was one of the worst reintroduction tests. I tested my fructose tolerance with orange juice.

Everything was fine on the first testing day, I did not get any symptoms. On the second day, it went wrong. Everything seemed fine the first few hours after drinking the orange juice, but then the fatigue set in.

I felt very tired for a few hours, and at night I woke up with the worst bloated stomach I ever had.

A few days of non-stop toilet visits followed. It took almost a week until my stomach was finally calm again. Since then I check food packaging very carefully and I stay away from high-fructose products as far as I can. 

Fructase review

Fructase is a supplement that contains the enzyme xylose isomerase. This enzyme helps your body to completely digest the fructose in food.

It turns the fructose in food into glucose, and makes sure that people with fructose malabsorption don’t develop any symptoms when they consume a product containing fructose.

I’ve been using Fructase for a while now, I bought it so I can take the supplement when I am eating out and I am not sure if something contains fructose or not. 

How do you use Fructase?

You take 1 to 3 capsules Fructase right before you are about to eat a meal that might contain fructose. After you take the supplement, it is active for 30 to 45 minutes.

When you are having dinner in a restaurant and both your starter and main course may contain fructose, it is wise to take supplements again before you start your main course.

This way you are sure that the supplement still works. You can take a maximum of 15 Fructase capsules per day. 

The test

Even though I’ve been using Fructase for a few years already, I have never consciously eaten a high-fructose product to test if the supplement actually worked.

I’ve been afraid to do this because of the heaviness of my previous reaction to fructose. I have only taken the supplements in restaurants when I wasn’t sure if there was any fructose in my food.

To test the supplements for you, I decided to consciously eat two high-fructose products and see if the supplements did their work. 

Test 1: Honey

I know for a fact that a very small amount of honey is enough for me to get symptoms. I once took a piece of Tony Chocolonely Milk Nougat chocolate at work. I thought I knew that this chocolate was safe, but I was wrong, because it contains honey.

I think I had only 20 grams of the chocolate, so it is impossible that there was a lot of honey in there, but in a few hours I got extremely tired and after that the stomach problems began. This is why I tested 1 teaspoon of honey with 2 Fructase capsules. 

Test 2: Orange juice

My fructose reintroduction test went wrong when I was testing orange juice. My second test was 150 ml of orange juice and that is where I got crazy bad symptoms. For this test, I took the same amount of orange juice with 3 Fructase capsules. 

When you are going to try these supplements, it is important to find out for yourself how many capsules you need to prevent symptoms.

This depends on the amount of fructose you eat and your level of tolerance. Every person might need a different amount of capsules to prevent symptoms.

disolut lutomerase


The Frutcase capsules work very well for me. Both tests went well and I did not get the fatigue or stomach problems that I usually get when I eat fructose. I generally try to avoid fructose, but these capsules are perfect to take when I go out for dinner and when I am not sure if my meal contains fructose.

The capsules give me a safe feeling, because I never want to experience  the symptoms that I got when I tested fructose again. I don’t use the supplements very often, so the last package I had lasted for 6 to 9 months. This is definitely worth the costs for me. 

If you want to try the capsules yourself, you can go to Intoleran’s website to order them. Intoleran is a Dutch company, but they ship to many countries across the globe.

A package of Fructase contains 36 capsules and costs €23,50. You can also order a sample package with 5 capsules for €2,95 when you first want to try out your reaction to the supplement. 

Did you already try this supplement? Let me know about your experience with the product! 

Other FODMAP supplements

Do you want more information about supplements that can help you to tolerate FODMAPs in your food? I have also written an article on lactase supplements, supplements that help your body to digest lactose. And an article about all FODMAP supplements that are available. 

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  • John Newman says:

    I’ll certainly be giving this a try. This is one of my worst triggers too. I’ve been looking for some kind of solution to this for a while now. Really miss honey and lots of other things too.

  • Carolyn Price says:

    I am in Australia and during my reading about my problem, fructose/fructans malabsorption, I have found an Australian company who makes two products. One is FrucMalEase containing only xylose isomerase and the other is FrucMal+ containing xylose isomerase and alpha galactosidase(for digesting fructans) As I am not always totally strict with my diet and then suffer the consequences I have just commenced taking the combined product, one with lunch and dinner. Hoping it works for me too. ?
    It’s always good to hear what works for other people. ?

  • Pradip M Gandhi says:

    What will happen ( side effacts ) if I take frucMal+ tablet for my fructose & fructan intolerance before my main meal , but if my meal does not contain any any fructose & fructan containing items in meal।

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