Last Updated: November 12  |  Download my FREE Leaky Gut Recovery Guide

It took me a long time to realize leaky gut was the culprit of my many health woes.

Which isn’t surprising.

After all, who’s walking around on a normal day thinking, “Hmmm, maybe my intestinal wall is hyperpermeable” (aka leaky gut).

But when I first suspected I had it, I did what everyone else would do…

…look for the best test for leaky gut and a list of the most common symptoms.

When I started researching all the different tests available and speaking to colleagues, I came across a variety of approaches to take.

Most were terrible in terms of scientific grounding and conclusiveness.

Thankfully with more and more research I eventually found a few worth considering.  And I’ll run through the 3 most popular ones below.

Most interesting of all, I’ll run you through a free testing protocol for leaky gut – I found this approach to be hugely helpful.

Let’s dive in!

P.S. if you find yourself with signs of leaky gut, check out my free 7-page leaky gut recovery guide.

Jump to a section

Test #1 – the lactulose & mannitol test for leaky gut
Test #2 – the blood zonulin test for leaky gut
Test #3 – microbiome testing for leaky gut
How to test yourself for leaky gut for free
10 symptoms & signs of leaky gut – plus the tests you can take to prove them
1)   Food allergies / intolerances
2)   Autoimmune conditions
3)   Small Intestinal Bacterial Overgrowth (SIBO)
4)   Inflammatory Bowel Disease, eg Crohn’s Disease, Ulcerative Colitis etc
5)   Digestive problems
6)   Skin problems like eczema, acne, Rosacea, Hives, Psoriasis, rashes etc
7)   Brain fog or general fatigue or chronic headaches
8)   Mood swings and depression
9)   Allergies, eg seasonal, pet etc
10)  Nutrient deficiencies
What you should really do today for leaky gut

Test #1 – the lactulose & mannitol test for leaky gut

Even though most experts tell me they no longer rely on this test, it is perhaps the most direct test for leaky gut, because it looks solely at how permeable your gut is.

And studies like this one have shown “Evaluation of intestinal permeability in this way provides an objective means of diagnosing food allergy [issues]”, i.e. leaky gut.

So it is not a bad test by any means.  Now the question becomes, how does the lactulose and mannitol test work?

Lactulose Mannitol Tests For Leaky Gut

Well, you simply consume 2 types of non-metabolized sugar, one with large molecules (lactulose) and one with small molecules (mannitol), and then your urine is analyzed to see which sugars passed through your system.

If the lactulose (larger molecules) find their way into your urine, your gut may be considered overly permeable, ie leaky.

Given its specialist focus it is considered the #1 test for leaky gut.

If you are interested in getting this test, thankfully it can be ordered to your home and is relatively cheap with prices starting from around $179.  True Health Labs offers the lactulose mannitol test at this price (not an affiliate link).

Test #2 – the blood zonulin test for leaky gut

This is the only real blood test for leaky gut syndrome and here’s how it works.

So the main thing to know is that zonulin effects the gatekeepers of your gut lining (the things that decide what gets through into your bloodstream and what stays out), a.k.a. Tight junctions.

Meaning it can change the size of the openings in your gut lining.  So more of it, means openings increase in size and the lining becomes more permeable / leaky.

Obviously we want some zonulin to ensure nutrients get through (and that’s why we have it). But too much and you can say hello to leaky gut!

This test is designed to see whether you have too much zonulin in your system and thus may have leaky gut. A more interesting question though is what causes zonulin levels to rise in the first place?

Because if we can answer that, we can fix the problem itself. Generally, gluten plays a big role, as does candida / yeast, harmful bacteria and parasites.

But in certain people, eg celiacs, zonulin can be found at high levels even without one of these four things!

Test #3 – microbiome testing for leaky gut

I’ve had the great pleasure of putting more stool samples in test tubes than any person ever should.  Sometimes I’ve felt like a fecal-crazed Heisenberg with my own spin off TV series…Breaking Biome.

Weird?  Oh, most certainly.  So why on earth do I do it?

Well, just like we get blood tests to see if there is something wrong with us, I get stool tests to see if there is something wrong with my gut health.

You see, the poor scientists analyzing my stool sample (the real unsung heroes of society!) will perform microbiome testing to determine what’s going on inside the jungle of my gut.

They’ll look for bacteria (good and bad), viruses, bacteriophages, fungi, yeast, parasites and all sorts of other goodies that may be contributing to my intestinal permeability, aka leaky gut.

With a particular focus on finding what potentially harmful organisms are present or otherwise out of balance.

And just as importantly, they will analyze what nutrients and toxins these organisms are producing from the foods I eat.

This is the sort of information my doctor and I can then use to take action to fix my gut health or otherwise optimize it.

Historically, microbiome testing has been pretty useless in terms of takeaways

In fact, if you asked me whether it was worth doing only 2-3 years ago, I would have said heck no!  I remember when I got my first few tests it was more out of scientific wonder, than anything else.

My doctor and I would be sitting there pouring over the data and just looking at each other going…okay, so now what?

It may as well have been jibberish.

But things are changing

Some companies are actually starting to deliver plain English results and most of all, tell you what you should do with the results they find!

i.e. instead of just sending you a complex and bewildering list of strains in your gut, they are now sending you individualized recommendations and lifestyle tips to improve your gut health and thus intestinal permeability.  This changes everything.

Unfortunately, there are dozens of companies out there offering what they say are the ‘most advanced’ tests.

But most are delivering nothing of the kind.

Ubiome and Biohm are not bad. The data they produce is solid. But the actionable takeaways are limited.

Thryve is doing interesting work too, but I feel their testing service is a loss leader for their follow up products. So I’m not totally sold on them.

My favorite company for micriobiome testing is Viome

Not only are they doing scientifically sound testing, but they’re also focused on the right things.

So instead of trying to sell you follow up products like other companies, they’re giving you simple-to-follow diet and lifestyle advice.

And I’m actually kinda amazed at what they’re able to tell from our stool samples now.

For example, they are now able to pinpoint specific foods that YOUR specific gut flora tolerates well and what foods it does not.  This puts a whole new spin on ‘reactive’ testing.

It is quite possible that this info can sniff out food sensitivities that no other test can.  And then by eliminating these foods, you could potentially say adios to food-based digestive problems almost overnight.

In other words, it is trying to deliver the benefits of a 3-month elimination-reintroduction diet, but without the painstaking effort from you.

Unsurprisingly, Viome’s testing service is priced higher than the likes of Ubiome, Biohm and Thryve. But for me, that’s because it is simply backed by better data and more useful results.

So is microbiome testing really worth it?

I would say it is NOT worth getting if you are feeling pretty good these days thanks to eating the leaky gut diet and living the clean lifestyle.  i.e. if it ain’t broke, there’s nothing to fix!

So if you’re one of my many readers who has managed to turn things around, then forget about it.

By contrast I would say it is worth trying if you…

  • Have done the leaky gut diet for 30 days, but still aren’t feeling better. i.e. the test could help you pinpoint some specific foods that may be holding you back.
  • Don’t have the time to do a 3-month elimination-reintroduction diet.
  • Want to find out what foods you can eat more of and which ones to hold off on. e.g. maybe legumes are fine for you.
  • Are interested to find out whether you have a specific bacteria or yeast overgrowth issue.
  • Already have a condition and want more info / data points to help you and your doctor manage it better.

If any of those points sound about right, then try this microbiome test by Viome.  It is not cheap, but by far the best consumer (at home) test you can do.

Even the microbiome-obsessed Dr Hyman recently said…

“Viome uncovered information I wasn’t aware of about my microbiome, providing me with ways to optimize my gut health and pave the path to healing”.

Perhaps coolest of all, in addition to getting food recommendations tailored to your specific microbiome, when you take the Viome test you now get access to an AI-powered healthbot that can further guide your day to day actions.

The robots sure are taking over!

How to test yourself for leaky gut for free

If you don’t like the idea of paying for expensive tests like those above, you can consider doing a simpler 2-pronged holistic test (with the supervision of your doctor of course).

I’ll run through how I have done this in the past.

First, I compared my personal health history against all the signs of leaky gut.

After seeing I had several of the signs (food sensitivities, stomach pains, heartburn, brain fog, unexplained fatigue, IBS, and asthma / an autoimmune disease), and previously suffered from other signs of leaky gut (like eczema), I decided that there was ‘more probability of leaky gut than not’.

Given I had not been able to find any other reasoned diagnosis for my collection of symptoms, I was more than happy to finally have a working hypothesis.

Next I decided to embark on a 90 day leaky gut ‘elimination diet’, paired with smart gut-supporting supplements like L-Glutamine, Digestive Enzymes and Probiotics (they are links to 3 articles on this site that explain how these 3 supplements can help).

I figured that if after 90 days the 7 signs I had of leaky gut were gone or severely diminished it was because my gut had healed (and was originally leaky).

Within the first month of this protocol I already experienced a decrease or elimination of the majority of symptoms.

Stomach pains gone. Heartburn non-existent. Asthma 80% reduced. It was amazing!

And after the full 3 months I was in rude health.

For example, I no longer carried antacids with me, rarely reached for my inhaler, woke up in the morning full of energy, worked all day with intense focus (and without coffee!), and I even noticed how much easier it was to gain lean muscle (probably because my body was able to absorb all the nutrition finally).

Whilst I could not be 100% certain I had leaky gut, I can be certain that the leaky gut recovery protocol, which you can find in my free guide here, worked to fix my health problems. And for me that is all the proof I need.

Of course n=1. In other words, this is but my own experience. Your results will differ, since everyone’s body is different.

But the great thing is that you have the power. First, check your personal health history against the 10 symptoms below. Then, consider a 90 day leaky gut protocol like me and see how you feel at the end. You should consult your doctor before undertaking such a protocol.

10 symptoms & signs of leaky gut – plus the tests you can take to prove them

If you have leaky gut there is also a good chance you’ll be experiencing several of these symptoms.

e.g. at my worst I was enjoying food intolerances, SIBO, all the digestive problems below (the trio of fun times!), several of the skin related issues, brain fog and nutrient deficiencies.

So don’t get overwhelmed or feel worried, if you find yourself nodding to several of the symptoms/signs below.

1) Food allergies / intolerances

As we know food sensitivities may arise when undigested food particles or toxins in general cross the (leaky) gut barrier and into your bloodstream.

So what we’re saying is that to develop a food intolerance, overly permeable gut lining is a prerequisite.

Basically here’s what happens: when food particles that shouldn’t make it through to your bloodstream, do make it, the body views these as intruders and works hard to raise the immune response and destroy them.

Unfortunately, it might continue doing this every time you eat certain foods, especially gluten and dairy (it is scared!).

And that’s the thing – foods you may have previously tolerated, can all of the sudden become intolerable, as the body is now fighting against them every time they show up.

Although you can do the elimination diet, like me, to see what foods cause you grief, there are certain foods that might only cause you subtle pain.

That’s where a food intolerance test comes into it. Without this test you won’t notice what those foods are and you might keep eating them, and thus experiencing ongoing, low level systemic inflammation.

Ie your leaky gut will never completely heal.

The main test to consider is the IgG food allergy test (other two are IgA and IgM)

Since you’re suspecting leaky gut may be part of your problem it is often worth getting a candida test as part of this allergy test.

All of this testing can be done from home with a simple dry blood collection.

These tests will then look to see if your body is producing high levels of antibodies in your blood.

Overall, this is an indirect blood test for leaky gut syndrome, so consider speaking to your doctor to see if it is worth taking (and paying for).

2) Autoimmune conditions

For certain AI conditions like Celiac Disease, there is a very strong link with leaky gut.

Whilst for other conditions (and AI related issues) like rheumatoid arthritis, Type 1 diabetes and asthma, the link is still strong, however it is not entirely clear which one causes the other.

As a lifelong asthmatic I decided to simply test things out for myself. I figured if I undertook a leaky gut recovery protocol and then my asthma symptoms reduced, then there was a high probability that leaky gut was a contributor to my asthma and not the other way around.

In my case, this turned out to be true. As my asthma decreased first to 80% and then to asymptomatic levels.

Everyone is different of course. That is why it is wise to consult with your doctor and see what sort of personal program you can create together.

3) Small Intestinal Bacterial Overgrowth (SIBO)

Bacteria is good. In fact gut flora accounts for up to 80% of our immunity! But too much of the bad stuff tips you out of balance and an unbalanced gut flora can lead to leaky gut itself. So a condition like SIBO is a good (leading) indicator that you might be suffering from leaky gut.

Thankfully, unlike leaky gut there is a simple breath test for bacteria overgrowth. It’s not simply, ‘does this person have bad breath / halitosis?’.

Instead, it’s the same test used to check for IBD and other GI disorders.

All you need to do is consume a sugar-based solution (lactulose again!) and then breathe into a test tube or balloon-style device. You can even do this at home and send the results in.

Basically what they’ll then look for is the level of certain gases like methane and hydrogen in your sample, which are produced by certain bacteria. Too high and you could have serious bacteria overgrowth.

If you take this test make sure you avoid probiotics for 1 week prior (check with your doctor) and avoid alcohol, veg and fruit for 48 hours before the test. Avoiding these ensures bacteria measurements are accurate.

4) Inflammatory Bowel Disease, eg Crohn’s Disease, Ulcerative Colitis or Diverticulitis

The link here with leaky gut is quite clear.

The generally accepted connection is that intestinal hyperpermeability starts, then it leads to the development of IBD. Said differently, if you have IBD, you have leaky gut.

There is no chicken and the egg problem here. Unsurprisingly then, there is also a strong connection between people who suffer with IBS and leaky gut.

5) Digestive problems

I’m not just talking about diarrhea, constipation and heartburn/reflux/GERD here.

But also more innocent things like excessive gas, bloating and burping.

As someone who carried Zantac around with them full time from the age of 15 (!) I was able to tick a few of these boxes.

Thankfully since I started eating clean and supplementing smart I haven’t experienced any of these digestion problems. Not needing to worry about running out of Zantac after a big dinner out is fantastic!

6) Skin problems like eczema, acne, Rosacea, Hives, Psoriasis, rashes etc

There is a long history of leaky gut leading to skin conditions. In other words, the connection is not new.

Probably most interesting is the speed at which these signs can disappear when you start following a proper leaky gut recovery protocol like this one.

7) Brain fog or general fatigue or chronic headaches

This is something that can indicate leaky gut, but only if you’re experiencing it despite sleeping and eating well.

Ie don’t use this to judge your chances of leaky gut if your overall health is in poor shape.

8) Mood swings and depression

Given 80% of your serotonin is housed in your gut, it is no wonder we call the gut the second brain.

So it is plausible to think that a leaky gut, which causes inflammation and havoc in general down there, could play a large role in how you feel. In fact, some studies have shown that up to 35% of depressed patients could have leaky gut.

9) Allergies, eg seasonal, pet etc

Having sensitivities to cute little puppies is not a life I want to live! Thankfully the connection with leaky gut is similar to food allergies, which means it can be fixed through sealing up the gut barrier and reinoculating your gut with probiotics.

10) Nutrient deficiencies

This one might perplex you somewhat.

So as we know leaky gut is a problem because it sees bigger particles pass through your gut lining that shouldn’t. But here’s the thing…

…leaky gut can also mess with your gut lining, or more specifically, your gut’s microvilli, in such a way that whilst they let the big baddies through (eg gluten), they stop letting the small good guys through (eg nutrients).

This can lead to nutrient malabsorption and vitamin & mineral deficiencies.

Worse yet, since the good guys aren’t getting through, there is no one there to detoxify all the antigens being produced by your enraged immune system! It’s a double whammy.

Thankfully there is a simple test you can do to see if you are nutrient deficient, and thus possibly suffering from leaky gut. It’s called an organic acid test.

You simply order a kit to your home, leave a urine sample and then post it back. But here’s the thing…the lab does not test your urine for nutrient levels themselves, but rather for the acid levels.

You see, high levels of acids – a byproduct of nutritional deficiency – will indicate much more accurately that your body is suffering malabsorption.

There are a few other signs of leaky gut to consider, eg autism, obesity etc, but for me the link is not quite there yet. I won’t be shocked if and when the link is established though.

What you should really do today for leaky gut

Instead of spending $100s, if not $1000s, on tests that will not necessarily give you a clear yes or no, you might want to consider simply starting on a leaky gut recovery protocol today (here’s mine) if you have one or more of the 10 signs of leaky gut.

And then when the protocol finishes try a provocation diet to see what foods you can and cannot tolerate (like I did).

Of course you should make this decision in consultation with your doctor.

Here is a PDF of the leaky gut recovery protocol I used to say goodbye to leaky gut. It includes instructions on what to do every step of the way. It is nice and simple too.

Happy reading!

Want a simple solution for your leaky gut that actually works?

Stop Googling till 3am, reading dozens of blogs or buying expensive courses. Instead, just download my FREE leaky gut recovery guide (PDF) below. Everything you need to know to is in this simple step-by-step guide.