Nature Reviews Neuroscience, Published online: 14 May 2026; doi:10.1038/s41583-026-01049-x Many physical, social, lifestyle and systemic body factors — collectively termed the ‘exposome’ — can influence brain and behavioural phenotypes across the lifespan. In this Perspective, Sarah Genon and colleagues examine how we can gain a better understanding of the exposome’s neurocognitive effects.