Abstract
This chapter critically examines current limitations and unresolved challenges in MSC–EV research and translation. It highlights issues related to biological heterogeneityBiological heterogeneity, standardization, dosing uncertaintyDosing uncertainty, delivery barriers, and safety concerns. Quantitative evidence from recent studies is used to illustrate variability and reproducibility challenges. The chapter proposes research priorities and practical strategies to address these limitations and advance the field toward clinical maturity.