The International Scientific Association for Probiotics and Prebiotics (ISAPP) convened a panel of experts to review and update the definition of synbiotics. The panel revised the definition to "a mixture comprising live microorganisms and substrate(s) selectively utilized by host microorganisms that confers a health benefit on the host." They emphasized that synbiotics do not necessarily need to be designed for cooperative function, distinguishing between complementary and synergistic synbiotics. Complementary synbiotics combine probiotics and prebiotics to achieve health benefits, while synergistic synbiotics are designed to enhance the health benefits of co-administered microorganisms through selective substrate utilization. The panel also discussed the evidence required for synbiotic formulations, safety considerations, and implications for stakeholders. They recommended that synbiotic research should be conducted in randomized, double-blind, placebo-controlled trials, with specific guidelines for population selection, intervention design, outcome measurement, and statistical analysis. The consensus aims to provide clarity and guidance to ensure the scientific validity and safe use of synbiotics.The International Scientific Association for Probiotics and Prebiotics (ISAPP) convened a panel of experts to review and update the definition of synbiotics. The panel revised the definition to "a mixture comprising live microorganisms and substrate(s) selectively utilized by host microorganisms that confers a health benefit on the host." They emphasized that synbiotics do not necessarily need to be designed for cooperative function, distinguishing between complementary and synergistic synbiotics. Complementary synbiotics combine probiotics and prebiotics to achieve health benefits, while synergistic synbiotics are designed to enhance the health benefits of co-administered microorganisms through selective substrate utilization. The panel also discussed the evidence required for synbiotic formulations, safety considerations, and implications for stakeholders. They recommended that synbiotic research should be conducted in randomized, double-blind, placebo-controlled trials, with specific guidelines for population selection, intervention design, outcome measurement, and statistical analysis. The consensus aims to provide clarity and guidance to ensure the scientific validity and safe use of synbiotics.