Estetrol Prevents Catagen Progression in Healthy and Female Pattern Hair Loss Hair Follicles Ex Vivo

The study investigates the effects of Estetrol (E4) on hair follicles from healthy females and female pattern hair loss (FPHL) patients. E4 treatment prolonged the anagen phase, increased keratinocyte proliferation, and enhanced dermal papilla (DP) activity in healthy hair follicles. In FPHL patients, E4 showed benefits such as prolonging anagen and increasing keratinocyte proliferation, despite variability among patients. E4 also supported the proliferation of K15+ stem cells in the bulge area of involved hair follicles. These results suggest that E4 could be a promising hormone replacement therapy (HRT) to prevent hair loss and follicle miniaturization in postmenopausal women with FPHL.