The skin microbiome in aging from ecological dysbiosis to molecular therapeutics

Skin aging is a progressive process driven by cumulative alterations in skin structure and function, resulting in a distinct clinical phenotype characterized by wrinkles, loss of elasticity, pigmentary changes, and impaired barrier integrity. Although intrinsic aging and environmental stressors are well-established contributors, the skin microbiome is increasingly recognized as an important regulator of cutaneous homeostasis through its roles in modulating immune responses, maintaining barrier function, and regulating metabolic homeostasis. Age-associated physiological changes in the host selectively reshape the composition and function of the skin microbiome, while the resulting microbial dysbiosis may, in turn, contribute to the development of skin aging phenotypes. Here, we summarize the mechanistic crosstalk between the aging host and the skin microbiome, with particular emphasis on how these bidirectional interactions contribute to the pathogenesis of geriatric dermatoses. We further evaluate emerging microbiome-based therapeutic strategies, ranging from ecological restoration to precision microbial modulation. Viewing skin aging through this ecological framework may provide a foundation for developing translational strategies aimed at promoting healthier skin aging.