561 Vellus-to-terminal hair follicle reconversion does occur in male pattern balding in a new humanized mouse model of androgenetic alopecia and is promoted by minoxidil and PRP

Based on trichogram evidence, it has been claimed that, once terminal (T) scalp hair follicles (HFs) have been fully miniaturized into vellus (V) HFs in androgenetic alopecia (AGA), these cannot be reconverted into T HFs, even under therapy (Rushton et al. Exp Dermatol 2022). If true, this would mandate early intervention in AGA management, and would render hair transplantation the only meaningful therapy for late-stage AGA. Given that hypertrichosis-inducing drugs and hormones can rapidly induce V-T HF conversion, we wished to probe the validity of this provocative postulate by generating irrefutable histological evidence, using our novel humanized AGA mouse model under long-term therapy with minoxidil (MXL) or platelet rich plasma (PRP).