Injectable Therapy for Androgenetic Alopecia: A Systematic Review.

BACKGROUND: Androgenetic alopecia (AGA) is the leading cause of patterned hair loss. Current therapies are limited, and injectable therapy has emerged for intradermal delivery of bioactive agents. Despite increasing use, protocols and outcomes remain heterogeneous. OBJECTIVE: To systematically evaluate the agents, techniques, efficacy, and adverse effects of injectable therapy for AGA. MATERIALS AND METHODS: A systematic review was conducted in July 2025 following Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. PubMed, Embase, and Scopus were searched using the terms "mesotherapy" and "AGA." Studies were screened for relevance, with 30 meeting inclusion criteria. RESULTS: Included studies comprised 7 interventional, 11 observational, and 12 descriptive reports. The most frequently studied agents were multivitamin and peptide formulations, followed by dutasteride, minoxidil, bicalutamide, growth factors, and finasteride. Techniques varied in needle type, depth, and dosing schedules. Reported outcomes ranged from increased hair density and shaft diameter to stabilization of shedding. Adverse events were generally mild but included paradoxical alopecia, scarring, and acute dermatitis. CONCLUSION: Injectable therapy may provide cosmetic benefit in AGA, particularly with dutasteride, but current evidence is limited by small sample sizes, variable protocols, and short follow-up. Standardized randomized trials are required before injectable therapy can be recommended as routine therapy.