Abstract
Skin aging is a complex biological process influenced by the interplay of intrinsic (chronological) and extrinsic (environmental) factors, culminating in visible changes such as wrinkles, laxity, and dyspigmentation. Intrinsic aging results from endogenous oxidative stress and cellular senescence, leading to reduced fibroblast proliferation, diminished collagen synthesis (notably types I and III), and fragmentation of elastin fibers. Concurrently, extrinsic aging, primarily mediated by chronic ultraviolet (UV) exposure (photoaging), exacerbates these effects through upregulation of matrix metalloproteinases (MMPs), degradation of extracellular matrix (ECM) components, and accumulation of abnormal elastin (solar elastosis). Additional contributors include decreased hyaluronic acid production, impaired barrier function, and accumulation of advanced glycation end products (AGEs). Modern anti-aging strategies target these pathways via retinoids, antioxidants, and cosmeceuticals aimed at collagen stimulation, oxidative stress neutralization, and epidermal rejuvenation. Understanding these mechanisms is critical for developing evidence-based interventions to mitigate cutaneous aging.
