Advances in skin aging: integrating epigenetic, cellular, and immune mechanisms for targeted therapy

As the largest and most externally exposed organ, the skin is particularly vulnerable to aging, rendering skin aging a widespread clinical and aesthetic concern. Driven by both intrinsic and extrinsic factors, skin aging is characterized by progressive functional decline and structural remodeling that compromise barrier integrity, disrupt dermal homeostasis, and ultimately diminish quality of life. At the upstream regulatory level, skin aging-associated epigenetic modifications drive epigenetic drift that compromises transcriptional fidelity and primes cells toward senescence. At the cellular level, regulatory mechanisms converge on cellular senescence and profound mitochondrial remodeling. At the microenvironmental level, the failure of senescent cell clearance (immunosenescence) and the emergence of a chronic pro-inflammatory milieu (inflammaging) create a self-reinforcing immune-inflammatory axis. This axis exacerbates cytokine production, extracellular matrix remodeling, and progressive tissue degeneration. We further highlight emerging mechanism-targeted interventions, including epigenetic and mitochondrial modulators, senotherapeutics, biologics, immunotherapies, regenerative and device-based therapies. A deeper understanding of these interconnected molecular mechanisms and targeted therapies may offer a roadmap for future therapeutic innovation and translational research in skin aging.