Biologic Improvement of Skin: Pathways and Activation of Stem Cells, Growth Factors, and Peptides.

Skin aging manifests as loss of collagen, thinning of the dermis, diminished epidermal turnover, and accumulation of senescent cells. Recent advances highlight the potential of biologic therapies-including stem cell secretomes, growth factors, peptides, and exosomes-to restore skin health at the molecular and cellular level. This review summarizes peer-reviewed evidence on biologic skin improvement, with emphasis on Klotho, growth factors, exosomes, bioactive peptides (including defensins), sirtuins, and senolytic approaches. Mechanistic pathways are presented, clinical outcomes are discussed, and practical considerations for facial plastic surgery are highlighted. Takeaway points underscore the synergy of combining biologic agents with established aesthetic procedures.