<![CDATA[Facial skin health results from a complex interaction between intrinsic biological processes and extrinsic environmental exposures, extending beyond the effects of topical skincare alone. This narrative review synthesizes evidence from original studies published between 2015 and 2025, retrieved from PubMed and Google Scholar using targeted search terms related to internal factors such as hydration status, hormonal regulation, and genetic variation, as well as external influences including ultraviolet radiation, air pollution, and light absorption. Eligible studies were full-text original articles in English or Indonesian that examined skin-active ingredients or physiological mechanisms affecting facial skin. The literature consistently identifies hydration as a fundamental determinant of skin elasticity, smoothness, and luminosity, mediated through corneocyte organization, lipid barrier integrity, and aquaporin-3–regulated water transport. Hormonal factors, particularly estrogen, play a critical role in maintaining dermal quality by stimulating collagen synthesis, enhancing skin thickness, and reducing oxidative damage. Genetic variability further contributes to individual differences in skin characteristics by influencing collagen density, antioxidant defense systems, pigmentation pathways, and inflammatory responses. External stressors significantly modulate these intrinsic processes, with ultraviolet radiation and air pollution accelerating skin aging through oxidative stress, collagen degradation, barrier disruption, and pigmentary alterations. In addition, light absorption and reflection at the skin surface, affected by sebum composition and optical properties of the stratum corneum, influence perceived skin tone and radiance. Collectively, the evidence underscores the importance of understanding how intrinsic and extrinsic factors interact to shape facial skin health. A holistic, evidence-based approach that integrates topical treatments with internal health optimization, hormonal balance, lifestyle modification, and personalized care strategies is essential for achieving and maintaining optimal facial skin condition.]]>
