Topical 4-Aminopyridine 5% in Male Androgenetic Alopecia: A Split-Scalp Exploratory Series

In a split-scalp exploratory series involving 10 male patients with androgenetic alopecia (AGA), topical 4-aminopyridine (4-AP) 5% solution combined with microneedling did not demonstrate any significant improvement in clinical, dermoscopic, or trichometric parameters. The study found no visible improvement in hair density or caliber, with a mean hair density increase of only +1.2 hairs/cm² on the 4-AP side compared to +0.8 hairs/cm² on the saline side, which was not statistically significant. The study highlights a translational gap between the regenerative effects of 4-AP observed in animal wound models and its lack of efficacy in treating AGA in humans. The small sample size and short follow-up period limit the generalizability of these findings, and the results do not support the use of 4-AP in AGA with the tested formulation and protocol.