Stem Cell Therapy for Stress Urinary Incontinence: Why Has Clinical Success Remained Limited?

Abstract Introduction and Hypothesis Stem cell therapy for stress urinary incontinence (SUI) has been pursued for more than a decade, supported by a compelling regenerative rationale and reassuring early-phase safety data. Yet clinical efficacy has remained modest, complete continence uncommon, and durability uncertain. Method In this Clinical Opinion, we argue that translation has stalled for reasons that are both biological and conceptual: heterogeneous cell products and manufacturing variability undermine reproducibility; endpoints and follow-up are insufficiently harmonized to benchmark against surgical standards; chronically fibrotic periurethral tissue may be biologically quiescent and poorly permissive for regenerative activation; and, fundamentally, continence is a biomechanical phenomenon that cell injections alone cannot replicate. Results We propose that future progress will depend on validated potency assays, mechanism-driven trial design, microenvironment priming strategies, and integration of regenerative biology with biomechanical reinforcement (e.g., scaffolds or biologically enhanced support constructs). Conclusion Until such integration occurs, stem cell therapy for SUI should remain investigational.