POSTBIOTICS: A SCIENCE-BASED, PLAIN-LANGUAGE Q&A GUIDE “Sometimes, gut health is shaped not only by ‘live bacteria’ but by the biological footprints they leave behind.” Postbiotic products are preparations built around inactivated microorganisms and/or their components, supported by evidence for a specific health benefit. Depending on the formulation, this may include heat-inactivated probiotic strains, defined cell fragments (e.g., cell wall components), standardized fermentation-derived biomass, or metabolite-rich fractions. Importantly, not every product marketed as “postbiotic” meets a consensus-style definition—what matters is a well-characterized composition, a plausible mechanism, and human data linking the preparation to a measurable outcome. When evaluating labels, look for strain identification (if applicable), the inactivation method, whether the preparation is standardized (dose-to-dose consistency), and a clearly stated target benefit. Postbiotics are not the same as probiotics or prebiotics: probiotics are live microorganisms; prebiotics are substrates selectively used by beneficial microbes. While postbiotics may reduce certain risks associated with live organisms, “non-live” does not automatically mean universally safe—people with complex conditions, medication use, pregnancy, or immunosuppression should still seek professional guidance to match product type, dose, and expectations.