What role does Cortisol play in gut health?

Cortisol, the primary stress hormone, influences gut health through several pathways. Elevated cortisol can increase intestinal permeability ('leaky gut'), alter gut motility, and negatively affect microbiome composition. Chronic stress with sustained high cortisol is associated with irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). The evidence comes mainly from mechanistic, animal, and observational human studies; randomized controlled trials demonstrating causality are limited. MyBody-X does not offer a specific cortisol test; hormone panels (e.g., in the fertility check) do not routinely include cortisol. Consumers should note that salivary or blood cortisol measurements have strong diurnal variation, and single readings have limited interpretability. Persistently high cortisol should be evaluated by a physician, especially if Cushing's syndrome or chronic stress is suspected. The overall evidence level is mechanistic; direct dietary or lifestyle recommendations for gut health based solely on cortisol levels are not well supported.