Evidence check: Stuhlprobe in the context of longevity

Stool sample analysis (microbiome testing) is increasingly marketed in the context of longevity, but the scientific evidence remains limited. The gut microbiome influences inflammation, metabolism, and immune function—all factors linked to aging. However, robust longitudinal studies proving that microbiome-based interventions extend human lifespan are lacking. Many commercial tests report only relative abundances of bacterial species without standardized reference ranges or clinical validation for 'longevity.' Additionally, the microbiome fluctuates significantly with diet and time of day, so a single stool test cannot reliably assess biological aging. The evidence is best described as 'mixed': there are mechanistic associations and some observational studies, but no strong clinical endpoints. Consumers should view these tests as exploratory and not base medical decisions on them. Safety note: if stool contains blood or persistent symptoms occur, consult a physician.