Leaky gut refers to increased intestinal permeability, a change in how substances pass through the intestinal lining.

Your intestinal barrier normally regulates the absorption of nutrients while helping limit the passage of potentially harmful substances. When barrier function is disrupted, permeability may increase.

Although increased intestinal permeability is a recognised biological phenomenon, “leaky gut syndrome” is not an established standalone medical diagnosis.

Increased intestinal permeability has been observed in several gastrointestinal conditions, including coeliac disease and inflammatory bowel disease.

Certain infections and medications, particularly non-steroidal anti-inflammatory drugs (NSAIDs), can also affect the intestinal lining.

Diet, alcohol intake, the gut microbiome and inflammatory processes are additional areas of research. However, the relationship between these factors and intestinal permeability varies, and an association does not necessarily mean one directly causes the other.

There is no medically established set of symptoms that specifically identifies increased intestinal permeability.

Symptoms such as bloating, abdominal discomfort, diarrhoea and changes in bowel habits are sometimes attributed to leaky gut, but they are common to many different digestive conditions.

Experiencing these symptoms does not establish that your intestinal barrier is impaired. Persistent or unexplained symptoms should be assessed by a healthcare professional to identify possible underlying causes.

A stool microbiome test analyses microorganisms present in the digestive tract. It can provide information about microbial composition and diversity, but it cannot directly measure intestinal permeability or diagnose leaky gut.

GiMap uses shotgun metagenomic sequencing to analyse microbial DNA within a stool sample.

Although research continues to explore relationships between the microbiome and intestinal barrier function, microbiome results should not be interpreted as proof that the gut lining is damaged.

The most appropriate approach depends on the underlying cause.

For example, in people with coeliac disease, following a strict gluten-free diet is an established part of treatment and can allow the intestinal lining to recover.

A varied, fibre-containing diet can support normal microbiome function, although no particular diet or supplement has been proven to treat increased intestinal permeability across all conditions.

If symptoms persist, identifying and managing an underlying medical condition is more important than relying on products marketed to “heal leaky gut”.

Scientists are investigating several approaches to understanding and supporting intestinal barrier function, including microbiome-targeted interventions, medicines that influence the intestinal lining, and experimental compounds involved in tissue protection and repair.

Prebiotics and probiotics. Researchers are studying whether particular dietary fibres and microorganisms can influence intestinal permeability. Some human studies have reported improvements in specific barrier-related measurements, although findings are inconsistent and more research is needed to establish which interventions may benefit which patients.

Intestinal barrier-targeting medicines. Experimental drugs such as larazotide acetate and IMU-856 have been investigated in people with coeliac disease. Larazotide's phase 3 trial was ended by its sponsor without completion, while early human research into IMU-856 has reported preliminary findings relating to intestinal tissue. Neither is an established treatment for leaky gut.

Experimental peptides. BPC-157 is a synthetic peptide first studied for its effects on the stomach and gut, and it has been investigated in animal models of gastrointestinal injury and tissue protection. Unlike most peptides, which are broken down quickly by stomach acid, BPC-157 has been reported to remain stable in human gastric juice, which is one reason it continues to attract research interest in digestive health. The research into BPC-157 is predominantly preclinical, and although some findings suggest effects relevant to gastrointestinal tissue repair, its safety and effectiveness for treating increased intestinal permeability in humans have not been established.

These approaches are at different stages of investigation and should not be considered proven treatments for leaky gut.