ABSTRACT Introduction: Alopecia, including androgenetic alopecia and alopecia areata, significantly impacts quality of life. Current treatments such as minoxidil and finasteride show variable efficacy and may be associated with adverse effects. Exosome-based therapies have emerged as promising cell-free regenerative approaches; however, their clinical efficacy and safety remain incompletely defined. Methods: We systematically reviewed the clinical efficacy and safety of exosome-based therapies for the treatment of alopecia. This systematic review was conducted in accordance with PRISMA 2020 guidelines and registered in PROSPERO. Searches were performed in PubMed/MEDLINE, Embase, Scopus, the Cochrane Library, and LILACS/SciELO up to September 2025. Randomized controlled trials, non-randomized comparative studies, and observational studies in humans were eligible. Study selection, data extraction, and risk-of-bias assessment were performed independently by two reviewers. Results: Seven clinical studies involving 323 participants were included, along with one additional pre-clinical study used to provide mechanistic context. The exosome-based interventions evaluated included preparations derived from mesenchymal stem cells, adipose tissue, platelet-rich plasma–associated vesicles, or follicular sources, and were delivered via intradermal injection, microneedling, or topical application. Across controlled and single-arm studies, exosome therapies were associated with improvements in hair density and thickness in several studies; however, the certainty of evidence was low, and results were heterogeneous. Reported adverse events were predominantly mild and transient, including erythema, edema, and injection-site discomfort, with no serious adverse events observed. Conclusion: Exosome-based therapies demonstrate promising signals of clinical benefit in alopecia, particularly regarding hair density and thickness, and appear to be well tolerated in the short term. Nevertheless, the overall certainty of the evidence is low, limited by small sample sizes, methodological heterogeneity, incomplete outcome reporting, and the absence of long-term safety data. Well-designed, large-scale, randomized controlled trials using standardized exosome characterization and delivery protocols are required to confirm these findings and support safe clinical translation.
Penha et al. (Sun,) studied this question.