Fibroblast Growth Factor-7 and Hair Biology: Bridging Basic Science and Therapeutic Applications.

Alopecia profoundly impacts psychological well-being and quality of life, yet current therapeutic options such as minoxidil and finasteride exhibit limited efficacy. Fibroblast growth factor 7 (FGF-7), also known as keratinocyte growth factor (KGF), is a paracrine growth factor secreted by dermal papilla cells that specifically activates the epithelial receptor FGFR2b. Receptor engagement triggers multiple downstream signaling cascades, including the MAPK/ERK, PI3K/Akt, and Wnt/β-catenin pathways, promoting keratinocyte proliferation, stem cell activation, and the transition of hair follicles into the anagen phase. Both in vitro and in vivo animal studies consistently demonstrate that FGF-7 accelerates telogen-to-anagen transition and enhances follicular regeneration. FGF-7 acts synergistically with insulin-like growth factor 1 (IGF-1) and vascular endothelial growth factor (VEGF) to sustain nutrient delivery and cell proliferation. Human scalp studies further reveal a strong association between the FGF-7/FGFR2b signaling and follicular activity; however, clinical trials remain scarce. Topical application of FGF-7 has demonstrated an excellent safety profile, whereas systemic administration necessitates careful monitoring. Future directions include the development of engineering to extend the systemic half-life, advanced delivery systems, and gene or mRNA-based therapeutic approaches. Thus, the FGF-7/FGFR2b axis is a highly compelling molecular target for next-generation hair regeneration therapies.