Increased intestinal permeability is real and measurable, and it shows up in coeliac disease, IBD, after hard exercise and in some other situations. "Leaky gut syndrome" as a standalone diagnosis that explains fatigue, brain fog and everything else is not an accepted medical condition. Colostrum has a genuine study on permeability in athletes at 20 grams a day; Gut Save has 15 milligrams. Treat the gut-barrier claim as a nod, not a promise.
'Leaky gut' is one of the most talked-about - and most misunderstood - concepts in gut health. It's used to sell countless supplements, including gut-barrier ingredients found in products like Gut Save. But what's real science and what's overstated? Here's an balanced explainer.
What Does 'Leaky Gut' Actually Mean?
The gut lining is designed to be selectively permeable - it lets nutrients and water pass into your body while keeping unwanted substances and microbes in the gut. The cells of this lining are held together by structures called tight junctions. 'Leaky gut' refers to increased intestinal permeability: when these junctions loosen and the lining becomes more porous than normal, potentially allowing substances through that normally wouldn't pass.
What's Real, and What's Overstated
This is where a careful guide has to be precise, because the topic is polarised. Here's the balanced picture:
What's Real
- Increased intestinal permeability is a genuine, measurable phenomenon. Scientists can measure it (for example, with lactulose/mannitol tests).
- It's associated with certain conditions - including celiac disease, inflammatory bowel disease, and some others - where the gut barrier is affected.
- Various factors can affect gut permeability, including certain medications (like NSAIDs), infections, and possibly diet and stress.
What's Overstated
- 'Leaky gut syndrome' as a stand-alone diagnosis that directly causes a huge range of unrelated symptoms (fatigue, skin problems, mood issues, and more) is not an established medical diagnosis.
- The direction of causation is often unclear: in many conditions, it's uncertain whether increased permeability is a cause, a consequence, or a bystander.
- Many products claim to 'cure leaky gut' with little solid evidence that they meaningfully change permeability or improve health outcomes.
The honest middle ground
Increased intestinal permeability is real and matters in certain medical conditions. But the popular concept of 'leaky gut syndrome' - a catch-all diagnosis blamed for every symptom and 'cured' by supplements - runs well ahead of the science. Be sceptical of products promising to 'seal' or 'cure' a leaky gut, while still taking genuine gut-barrier health seriously through diet and lifestyle.
Gut-Barrier Ingredients in Supplements
Several ingredients are marketed for 'gut barrier' or 'leaky gut' support, and some appear in Gut Save:
- Colostrum: has some genuine research for supporting the gut barrier and reducing permeability - but mostly in specific contexts (like athletes or NSAID use) and often at higher doses than supplements provide. Gut Save contains 15 mg, a small amount.
- Collagen: marketed for the gut lining, but as we cover in our collagen article, direct human evidence for gut healing is limited.
- L-glutamine: another popular gut-barrier ingredient (not the focus of Gut Save) with some supportive but limited evidence.
So while some gut-barrier ingredients have a basis, the evidence is generally modest, doses in broad supplements are often small, and none is a proven 'cure' for leaky gut.
How to Genuinely Support Your Gut Barrier
The most evidence-based ways to support a healthy gut barrier are - once again - foundational:
- Eat plenty of fibre: gut bacteria ferment it into butyrate, which nourishes the cells lining your gut and supports barrier integrity.
- Eat a diverse, whole-food diet: supports a healthy microbiome, which helps maintain the barrier.
- Include fermented foods for microbial diversity.
- Manage stress and sleep well: both affect gut function and possibly barrier integrity.
- Limit excess alcohol and NSAIDs where possible (NSAIDs can increase permeability).
- Avoid smoking and limit ultra-processed foods.
These do more for your gut barrier than any 'leaky gut' supplement. If you have symptoms you suspect are gut-related, the best step isn't a supplement - it's a proper medical evaluation, because real conditions that affect the gut barrier (like celiac disease or IBD) need diagnosis and treatment.
Important: 'Leaky gut syndrome' is not an established medical diagnosis, and no supplement is a proven cure for increased intestinal permeability. If you have persistent digestive symptoms, or red-flag symptoms like blood in the stool or unexplained weight loss, see a doctor - conditions that affect the gut barrier, such as celiac disease and IBD, require proper medical diagnosis and treatment. Don't rely on supplements to 'cure' a self-diagnosed leaky gut.