Targeting skin barrier repair: mechanisms of action, therapeutic evidence, and clinical translation challenges of mesenchymal stem cell-derived exosomes

• MSC-exos restore skin barrier integrity by modulating physical, immune, microbial, neural, and pigmentary components through molecular cargo transfer. • Exosome efficacy is influenced by MSC source and preconditioning, with bioengineering approaches enhancing therapeutic potential. • Preclinical evidence supports MSC-exos as a promising cell-free therapy for skin barrier repair, comparable or superior to parent cells. • Key translational challenges include standardization, scalable manufacturing, and regulatory pathways, which must be addressed for clinical application.