GLP-1 May Play a Hidden Role in Irritable Bowel Syndrome

This is a narrative review published in Experimental Physiology that synthesizes evidence from basic science, neuroendocrinology, and clinical observations to build the case for GLP-1's involvement in IBS pathophysiology. It examines L-cell biology, GLP-1 signaling pathways, and their intersection with known IBS pathophysiological mechanisms.

With millions of people now taking GLP-1 drugs for weight loss and diabetes, understanding GLP-1's effects on gut function is increasingly important. This review suggests these drugs may have unrecognized effects — positive or negative — on IBS symptoms. It also opens a new therapeutic avenue for IBS, a condition with limited effective treatments, by targeting a well-characterized peptide pathway.

This review bridges two major research areas: the GLP-1 revolution in metabolic medicine and the growing understanding of the gut-brain axis in functional bowel disorders. As GLP-1 drugs become some of the most prescribed medications in the world, their effects on gut motility, visceral pain, and the microbiome are gaining urgency. Anecdotal reports from GLP-1 drug users about changes in bowel habits align with the mechanisms described here.

As a review, no new experimental data is presented. The evidence linking GLP-1 to IBS is largely mechanistic and inferential — the clinical evidence is limited to one mention of a GLP-1 mimetic reducing IBS pain. The heterogeneity of IBS (different subtypes, triggers, and mechanisms) makes it difficult to assign a single peptide a central role. The review focuses on GLP-1 but IBS involves many other peptides and signaling molecules.