Healthy skin, Healthy brain

Skin aging extends beyond aesthetic concerns and is increasingly recognized as a key contributor to brain aging through neuroendocrine, inflammatory, and neurochemical mechanisms. Traditionally considered as a peripheral barrier, the skin is now recognized as a neuroendocrine organ capable of communicating with the central nervous system (CNS) via hormone secretion, cytokine signaling, and neurotransmitter modulation. Recent literature has begun to formalize the concept of the skin-brain axis as a bidirectional communication system, particularly within the contexts of psychodermatology and neuroimmunology. This review highlights how extrinsic factors such as ultraviolet (UV) radiation and intrinsic aging disrupt skin homeostasis and trigger systemic effects on brain functions. Chronic UV exposure activates the cutaneous hypothalamic-pituitary-adrenal (HPA) axis and increases systemic cortisol levels, impairing hippocampal neurogenesis and cognitive function. UV-induced alterations in neurotransmitters including glutamate, dopamine, and β-endorphins affect learning, memory, and emotion regulation. Importantly, both photoaging and natural skin aging are associated with reduced synthesis of brain-derived neurotrophic factor (BDNF) in the skin, potentially diminishing systemic BDNF availability, and contributing to cognitive decline. Recent studies explored the protective effects of sunscreen and moisturizers in mitigating cutaneous inflammation and reducing neurodegenerative risk. Additionally, topical or dietary interventions, such as plant-derived polyphenols, may restore skin BDNF levels and enhance skin-brain resilience. Collectively, these findings support a paradigm shift: preserving skin health is not only a dermatological goal, but also a promising strategy for mitigating brain aging and promoting cognitive resilience.