Intradermal Injection in Balding Region Versus Intramuscular Injection in Surrounding Muscles: A Split-Scalp, Randomized Trial on Botulinum Toxin for Androgenetic Alopecia

This split-scalp, randomized trial involving 29 patients compared intradermal versus intramuscular botulinum toxin (BoNT) injections for androgenetic alopecia (AGA). Intramuscular injections significantly improved hair density more than intradermal injections (p<0.001), though both methods increased hair diameter similarly (p=0.433). Intradermal injections were more painful (p=0.036), and one case of alopecia areata was reported. The study suggests the need for personalized treatment approaches and further research to optimize BoNT injection protocols for AGA.