Impact of stress on hair pigmentation: Neurobiological depletion of melanocyte stem cells

Hair pigmentation is a complex biological process regulated by the number and activity of melanocytes in the hair follicle. Although the classical understanding of hair graying is that the aging process is the primary factor, modern research increasingly suggests that psychological and physiological stress also significantly contribute to premature depigmentation. Objective: This study aimed to analyze the biological mechanisms by which stress affects hair pigmentation, with a focus on the neural regulation of melanocyte stem cells. Methods: A mechanistic research approach was applied using a systematic review of experimental and translational studies published between 2000 and 2025. The emphasis was on neurobiological, cellular, and molecular data describing stress-induced changes within the hair follicle. Results: The study shows that stress activates the sympathetic nervous system, leading to excessive release of norepinephrine in hair follicles. This signal induces premature differentiation and depletion of melanocyte stem cells (McSCs), resulting in irreversible hair depigmentation. These results support the idea that stress-induced hair graying is a neurobiological process of aging and not a purely cosmetic or chronological phenomenon. A detailed overview of the processes may contribute to the development of future preventive or therapeutic strategies.