Therapeutic Effect of Botulinum Toxin on Scalp Alopecia: Physiopathology and Reported Cases - A Systematic Review

The systematic review from December 2019 assessed the potential benefits of botulinum toxin as a treatment for scalp alopecia, examining 6 studies with a total of 94 patients. The majority of these patients had androgenetic alopecia, with a few cases of alopecia areata and one case of radiation-induced alopecia. Treatment protocols varied, with doses ranging from 30 to 150 units and 1 to 12 sessions. While four studies reported improvements in hair growth and two showed increases in hair density, the review highlighted the low level of evidence and the heterogeneity among the studies, including differences in patient populations, treatment protocols, and evaluation methods. The largest study included only 50 patients, and objective measurements such as hair density and growth rate were often lacking. Despite high patient satisfaction and no significant adverse effects reported, the review concluded that there is not enough scientific data to confirm the efficacy of botulinum toxin for alopecia treatment, emphasizing the need for more rigorous randomized controlled trials.