Homeodynamic Rejuvenation: an adaptive framework for resetting skin aging.

Skin aging reflects not only the accumulation of molecular damage, but also a progressive decline in the skin's ability to restore equilibrium under continuous environmental stress. Classical models distinguishing intrinsic and extrinsic aging do not fully capture this dynamic process. In this article, we introduce Homeodynamic Rejuvenation as the restoration of functional competence and biological vitality, achieved not through reversal of visible signs of aging, but by re-establishing the skin's ability to detect stress, coordinate adaptive responses, and recover efficiently following perturbation. Central to this framework is the concept of homeodynamic plasticity, which reflects the skin's intrinsic capacity to dynamically sustain function under environmental and metabolic stress. By integrating principles of homeodynamics with exposome biology, this approach targets the reactivation of the cellular systems that govern stress sensing, repair, and recovery. Five core biological processes, namely, intracellular quality control, regenerative competence, metabolic resilience, cellular integrity, and structural integrity, underpin homeodynamic plasticity. Disruption or failure of one or more of these processes results in progressive functional decline, culminating in skin aging, of which dermatoporosis, a chronic cutaneous insufficiency syndrome, represents a terminal manifestation. These interconnected processes provide a coordinated basis for both restoring and assessing skin function. We propose that Homeodynamic Rejuvenation is best evaluated through dynamic perturbation-recovery kinetics, which quantify the skin's ability to respond to and recover from stress. By linking these biological processes to measurable functional and clinical outcomes, Homeodynamic Rejuvenation offers a structured and translational framework for quantifying and restoring skin resilience.