Stem cell–derived conditioned medium for alopecia: A systematic review and meta-analysis

Background: Alopecia is a common and distressing medical condition that has been related to psychiatric disorders. Stem cell–derived conditioned medium (CM), a novel therapy for hair regeneration, has shown effectiveness in several trials. Methods: This meta-analysis aims to explore the effectiveness of stem cell–derived CM in improving hair growth for patients of alopecia. We prospectively registered this systematic review and meta-analysis in PROSPERO (CRD42023410249). Clinical trials that the enrolled participants suffering from alopecia applied stem cell–derived CM were included. We calculated the mean and standard deviation for the hair density and thickness. Results: Ten clinical trials were included in our analysis. On the basis of eight clinical trials (n = 221), our pooled results indicate that stem cell–derived CM is effective in increasing hair density (mean difference [MD]: 14.93, confidence interval [95% CI]: 10.20–19.67, p < 0.0001) and thickness (MD: 18.67, 95% CI: 2.75–34.59, p < 0.0001) (μm) in patients with alopecia. Moreover, our findings suggest that longer treatment duration is associated with significantly greater improvement than shorter treatment duration (p = 0.02). Three of the included studies were randomized controlled trials (RCTs), and when we specifically analyzed these RCTs; statistical significance could also be observed in terms of hair density (MD: 9.23, 95% CI: 1.79–16.68, p < 0.00001). Key messages: Stem cell–derived conditioned medium can effectively increase hair density and thickness for alopecia, and there is no difference between each method (topical application, microneedling, or injection).