More than a simple probiotic-prebiotic combination, synbiotics are a mixture of live microorganisms and substrate(s) that  confer health benefits to the host either by complementary or synergistic effects.¹

Pro- and prebiotics in a mixture can each work independently to achieve certain health benefits within one formulation. However, depending on their type and nature, the live microbes and selectively-utilized substrate can also synergistically work together to bring health benefits that are not possible with microbes, or their substrates, when used alone.¹

1- Swanson et al, 2020; Nat Rev Gastroenterol Hepatol