Kaempferol Enhances Hair Growth by Regulating JAK3/STAT6 and TGF-β/Smad Signaling in Human Dermal Papilla Cells and a C57BL/6 Mouse Model

Kaempferol, a flavonoid found in hair growth-promoting plants, was studied for its effects on hair loss prevention. It significantly enhanced human dermal papilla cell proliferation in a dose-dependent manner, surpassing the effects of minoxidil. Kaempferol inhibited TGF-β1-induced Smad-binding activity by 65.8% and IL-4-induced STAT6 activity by 72.5%, compared to finasteride and tofacitinib. Western blot analysis showed suppression of phosphorylated Smad2/3 and STAT6, and upregulation of CDK2, CDK4, cyclin D3, ERK1/2, IGF-1R, and VEGFR-2. In C57BL/6 mice, topical application of Kaempferol significantly promoted hair growth, increased follicle numbers, and improved hair thickness. These results suggest that Kaempferol enhances hair growth by modulating TGF-β/Smad and JAK3/STAT6 pathways, indicating its potential as a natural therapeutic agent for hair loss treatment.