Skin aging reflects both intrinsic biological decline and extrinsic influences collectively known as the skin exposome, including ultraviolet (UV) radiation, air pollution, psychosocial stress, fatigue, sleep disruption, and suboptimal lifestyle behaviors. These factors contribute to cumulative molecular and structural damage, positioning the skin as both a visible marker of whole-body aging and a target for longevity strategies. This review examines the validity of an integrative "In and Out" a...