Myths vs facts: Leaky Gut Test and Schlaf

The combination of 'leaky gut' testing and sleep is an area rife with myths but lacking robust evidence. 'Leaky gut' (increased intestinal permeability) is not a recognized clinical diagnosis. Tests measuring zonulin or lactulose/mannitol ratios in urine are offered by direct-to-consumer labs but lack standardized validation. There are no established reference ranges, and results vary with diet, stress, and time of day. Claims that a 'leaky gut' directly causes sleep disturbances are speculative. While impaired gut barrier could theoretically affect sleep via inflammatory pathways, rigorous human studies are absent. Sleep issues are multifactorial (stress, hormones, behavior, genetics). Single factors like CRY1 variants have only small effects. The evidence for such home tests is marketing-driven and not clinically confirmed. Consumers should be skeptical and avoid making health decisions based on these tests. Consulting a doctor for sleep hygiene and organic causes is more appropriate.