Comparison Between Subcutaneous vs. Combined Subcutaneous and Intramuscular Application of Botulinum Toxin for Androgenetic Alopecia: A Randomized Clinical Trial

This randomized clinical trial involving 15 men assessed the efficacy of botulinum toxin A for androgenetic alopecia (AGA) by comparing subcutaneous (SC) application alone to combined subcutaneous and intramuscular (IM+SC) application. Over 6 months, both groups experienced a significant reduction in hair thickness in the frontal region, but no significant changes in hair density or the ratio of vellus to terminal hair. The IM+SC group showed a significant decrease in terminal hair in the frontal region, unlike the SC group. No significant differences were observed between the groups in any evaluated parameters, including global photographic assessment. The study concluded that botulinum toxin A may not significantly improve hair density or thickness in AGA patients, highlighting the need for alternative treatments with proven efficacy. Mild to moderate pain was reported during the procedure, but no serious adverse effects occurred. Limitations include a small, heterogeneous patient population and lack of a placebo or control group.