This study examines how ultraviolet (UV) radiation influences the molecular aging process of human skin by comparing sun-exposed neck skin with sun-protected chest skin across various age groups. UV exposure accelerates and fundamentally alters aging pathways. Photoaged neck skin shows faster and more severe age-dependent transcriptomic dysregulation than chest skin. The transcriptomic dysregulation was observed in major pathways related to DNA damage response, stress signaling, metabolic programming, and oncogenic transformation. Sirtuin (SIRT1 and SIRT5) depletion is a hallmark of photoaging, with SIRT1 specifically linked to attenuated AMPK signaling in middle age. While Intrinsic aging is more gradual and homeostatic, sun-protected chest skin shows a progressive decline in metabolism and immune vigilance. Measurements of collagen fibers and autofluorescence intensity were conducted using a label-free, non-invasive two-photon imaging system.