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How to Check If You Have a Leaky Gut?

Imagine going to a doctor with eczema and instead of getting a skin cream, you’re told to take a probiotic and get tested for leaky gut syndrome. How is a skin rash connected to a leak in the gut? Where does that leak even go? And why would a probiotic fix it? Why do other doctors roll their eyes when you mention leaky gut? Are they just bad doctors?

These are some of the questions I’ve been asking myself while writing this article because the following common conditions are connected with leaky gut syndrome:

And those connections above are just a drop in the bucket. Google returns over 10 million results for the “leaky gut syndrome" search. Reputable health organizations like the Cleveland Clinic, WebMD, Harvard Health, and Healthline have extensive content on it. Even academic reviews on PubMed and NIH-related sites feature it prominently.

Technically speaking, everything inside the body is interconnected via the same immune, nervous, hepatic, lymphatic, endocrine, metabolic, digestive, and other systems. The first problem starts when these connections are made up out of thin air because the human gut is LEAKY by design!

I know that much from my medical training and almost three decades of researching and writing about nutritional and gastrointestinal disorders. That is also why I said in the lead: "any effort to 'plug the leak' may literally starve you to death."

The second, and an even greater, problem is that all of those digestive, cognitive, topical, inflammatory, mood, hormonal, metabolic, and immune are as real as it gets, but because of that nonsense with leaky gut, people who are affected by them, perhaps, you too among them, AREN'T GETTING a proper diagnosis and treatment.

Is it normal in 2025? No, it's not only not normal, but it's totally nuts.

How Come Everyone Else But You Are Wrong?

Good question! Let me give you a factual explanation, not just a strong opinion so that you can judge for yourself. Here is how the proponents of the "leaky gut" myth describe it:

"When you have a leaky gut, certain tiny particles that should never be able to enter your bloodstream start to make their way through. [...]
The result? A disruption of acute inflammation and sometimes autoimmune reactions. A normal part of your immune response that serves to fight infections and diseases winds up over-performing, leading to chronic inflammation, which is at the root of most diseases [link]."

Here is another take on the same topic:

"As the theory goes, the intestinal mucosal barrier becomes increasingly permeable, allowing harmful toxins and bacteria to enter the bloodstream and cause havoc throughout the body [...] Many experts agree that the disorders most strongly correlated with increased intestinal permeability and barrier dysfunction are inflammatory bowel disease (IBD), irritable bowel syndrome (IBS), and celiac disease [link]."

Let’s see what’s wrong with those and other similar explanations of the “leaky gut” myth:

The gut is, indeed, leaky like hell, and that is by design!

Absorbing fluids, nutrients, vitamins, minerals, and microelements is the PRIMARY function of the gut. The small intestine is intentionally permeable to all of the substances that reach it. The degree of its permeability is nothing short of incredible:

"The wall of the small intestine is composed of the same four layers typically present in the alimentary system. However, three features of the mucosa and submucosa are unique. These features, which increase the absorptive surface area of the small intestine more than 600-fold, include circular folds, villi, and microvilli (Figure 2). These adaptations are most abundant in the proximal two-thirds of the small intestine, where the majority of absorption occurs [link]."

I intentionally selected this quote from an open-source “Anatomy & Physiology” college-level textbook to avoid being accused of confirmation bias and help you learn more about this fascinating subject.

Plugging up gut leaks will kill you in no time!

If the gut stops being permeable to fluids, nutrients, and even presumed "harmful toxins and bacteria," then a person would pass away from dehydration within a week.

And would it make any difference if a “leaky gut” were 1,200 times more absorbent than 600-fold? No, it wouldn’t because once a harmful substance has reached the bloodstream, past a certain threshold, the harm is all the same.

You can only control what passes your lips but not what passes the gut. The small and large intestines do not possess a magical ability to block harmful substances from entering the bloodstream.

If this were otherwise, none of the oral medicines comprised of large organic or inorganic molecules would work; alcohol wouldn’t make you drunk; caffeine wouldn’t cause you a high, and none of the toxins would have been able to cause food poisoning or foodborne infection.

Yes, the gut can leak, but only down the sewer!

The intestinal disorders that are most commonly associated with the “leaky gut” theory are, respectively, Celiac Disease (CeD), Crohn’s Disease (CD), and Ulcerative Colitis (UC), known collectively as Inflammatory Bowel Disease (IBD).

The mucosal membrane’s inflammation is the body’s core response to substances that cause strong immune reactions. The primary function of inflammation is to block and expel offending substances via diarrhea. Thus, ironically, intestinal inflammation is the complete opposite of the “leaky gut” because when it happens, the “leak” goes into the sewer, not blood.

For what it’s worth, let’s hear from the real scientists!

What's truly bizarre is that four of the most frequently cited articles in support of the “leaky gut” theory have not actually provided any conclusive evidence regarding the existence of the “leaky gut syndrome” as a bona fide clinical condition. Let’s check them out:

  1. The Discovery of Epidermal Tight Junctions. Ozawa T, Sugawara K, Tsuruta D.; Experimental Dermatology, Jun 23, 2014 [link].

    This study has zero relevance to the “leaky gut syndrome” because it investigates the permeability of the skin and not the intestines. In fact, the entire high-end cosmetic industry was built on the premise of the skin’s permeability to countless rejuvenating and moisturizing substances, and from their perspective, the “leakier,” the merrier.

  2. The Intestinal Barrier: a Fundamental Role in Health and Disease. Vancamelbeke M, Vermeire S.; Expert Review of Gastroenterology & Hepatology, Jun 26, 2017 [link].

    This article from 2017 doesn’t provide any evidence regarding the existence of the “leaky gut” and mentions it only once in connection with “anxiety, depression, and fatigue.” It is also skeptical regarding permeability tests intended to screen patients for “leaky gut:”

    "In general, we should be aware that more and more extra-intestinal disorders are being associated with gut barrier defects, but not all are supported by scientific data. Nowadays, commercially available permeability tests claim to evaluate if one has a leaky gut to explain systemic symptoms and disorders like concern, depression, and fatigue. Until there is scientific proof for the relevance and potential causal effect of barrier defects in these disorders, results from such tests should be interpreted with the necessary criticism."

  3. Intestinal Permeability Defects: Is It Time To Treat? Odenwald MA, Turner JR.; Clinical Gastroenterology and Hepatology, Sep 2013 [link].

    This article echoes my statements that intestinal permeability isn’t an enemy and “can be beneficial,” that by itself it doesn’t “cause disease,” and points out that blocking permeability (i.e., “barrier restoration”) didn’t demonstrate [results] in clinical trials:”

    "Finally, increased intestinal permeability can be beneficial in some contexts, e.g., in promoting nutrient and water absorption or activating protective immunoregulatory processes. [...] Finally, both human and mouse studies have made it clear that intestinal barrier loss alone, whether from tight junction dysregulation or epithelial damage, is insufficient to cause disease in an otherwise healthy individual. [...] Proponents claim that barrier restoration will cure the underlying disease, but this has not been demonstrated in clinical trials."

    Also, the authors have raised a valid concern regarding the “cures” marketed to treat “leaky gut:”

    "For those complaining of leaky gut syndrome, the increased intestinal permeability present is as likely to reflect the underlying disorder as to be a cause of the pathogenic process. Thus, the leaky gut cures being sold at a variety of internet sites and alternative medicine stores should be considered with caution. None have been tested in randomized clinical trials, and they may do more harm than good."

  4. The Intestinal Epithelial Barrier: A Therapeutic Target? Odenwald MA, Turner JR.; Nature Reviews: Gastroenterology & Hepatology, Jan 14, 2016 [link].

    This highly technical article is from the same authors as in the second source, and it's equally inconclusive:

    Intestinal barrier function has been associated with an increasing variety of diseases – both intestinal and systemic – and has led to the popularization of the catch-all diagnosis of 'leaky gut syndrome.” The vast majority of these associations are merely correlative, but experimental evidence relating barrier dysfunction to disease pathogenesis exists in some cases, including inflammatory bowel disease and celiac disease.

As you can see, these articles are far from complimentary. I am guessing the proponents of the leaky gut syndrome hypotheses were expecting that nobody would read them. Well, I did.

A case of mistaken identity

As strange as it is, the “leaky gut” diagnosis is far more prevalent in mental and neurological disorders than in the field of gastrointestinal (gut) disorders.

What is so strange about it? Most mental disorders, such as anxiety, depression, chronic fatigue, and neurological conditions, such as autism, schizophrenia, dementia, Parkinson’s, and Alzheimer's diseases, take root not from what “leaks” into the blood but from what's missing from it or not getting into it.

That is because the chronic inflammation of the small and large intestines blocks essential nutrients (proteins, fats, minerals, vitamins, and microelements) from absorbing and causes chronic undernutrition or outright malnutrition, the primary drivers of all mental and neurological disorders. In turn, treating the “leaky gut” by inhibiting the absorption of nutrients even more will only speed up the progression and severity of all of these disorders.

Hell is [often] paved with good intentions

I believe that people who have been advancing the concept of the leaky gut, however well-meaning they may be, have confused academic studies of intestinal permeability like the ones I cited above with autoimmune intestinal disorders and incorrectly attributed them to this myth.

Making up a standalone “syndrome” ignores the underlying causes and gives patients a false impression that they’re suffering from something novel rather than from a known and manageable disease.

Worse, this framing encourages people to seek treatment protocols aimed at “sealing the gut” without addressing actual causes. In many cases, these interventions may actually worsen outcomes by further restricting food diversity, suppressing digestive function, and promoting dependency on harmful therapies.

Finally, follow the reverse money trail

The leaky gut syndrome has not been recognized by insurance companies, hospitals, and Big Pharma as a coded and billable clinical condition. Ask yourself: would profit-hungry medical oligarchy say no to making money from a profitable condition that affects tens of millions of Americans? Yes, it would if only this condition would have existed.

Takeaways

I realize that among certain practitioners, my findings in this article will be just as popular as drilling a tooth without anesthesia. But, darned it, healthcare isn’t a popularity contest. With that in mind, here are succinct, no-holds-barred takeaways from this article, and I hope you’ll take them as far away as possible:

To summarize, don't become an easy dupe for the "leaky gut" ruse! Most of the causes behind conditions associated with this fraud are well known and easily alleviated by eliminating offending substances from your diet, and I will discuss them in the next article.

Author's Note

My goal here is not to dismiss the concerns associated with the “leaky gut,” but to steer well-meaning practitioners and patients toward better explanations and safer outcomes.

Still, I remain puzzled by how some equally “classically" trained medical professionals fall prey to this nonsense. They study physiology in detail, memorize the layers of the intestinal wall, learn the mechanisms of absorption and secretion, and know full well that the gut is super absorbent by design.

If you ever hear a medical professional mention “leaky gut,” run for your life because you don’t want to entrust your health care to someone with a leak in their brain.

Good God, forgive me for offending so many of my peers!

Amen!