Estetrol Prolongs Anagen Ex Vivo: Does E4 Have Potential as a Novel Strategy to Treat Female Pattern Hair Loss?

This study investigated the effects of Estetrol (E4) on hair follicle (HF) function using microdissected HFs from 4 healthy female donors over 50 years old. The application of 3μM E4 significantly prolonged the anagen phase, increased the number of proliferating hair matrix keratinocytes, and enhanced dermal papilla (DP) inductivity. E4 treatment also reduced DP stalk and dermal cup cell numbers, indicating protection from DP fibroblast emigration, and expanded the HF stem cell progeny pool. These findings suggest that E4 has the potential to prevent HF miniaturization and could be a promising treatment strategy for female pattern hair loss (FPHL).