What should I know about leaky gut tests?

Leaky gut tests (often stool panels measuring zonulin, LPS, actin, or occludin) are marketed by many labs as indicators of increased intestinal permeability. However, the scientific evidence is weak: stool zonulin does not reliably correlate with actual permeability, and standardized reference ranges are lacking. No current clinical guidelines (e.g., DGVS, AGA) recommend these tests for routine diagnosis. They can produce false positives or negatives, leading to unnecessary diets or supplements. A more evidence-based approach is medical evaluation for persistent GI symptoms, using established methods like lactulose/mannitol testing or endoscopy with biopsy. The provided context contains no validated studies on leaky gut tests; evidence is therefore rated as marketing/unclear. Consumers should be cautious and not base major health decisions solely on such tests.