Effects of Gymnema sylvestre Leaf Extract Formulation on Hair Growth Inhibition in C3H mice

This study was done to evaluate the hair growth inhibitory effect and underlying mechanism of Gymnema sylvestre leaf extract (GSLE). Vehicle, L-product, or 5% GSLE formulation was topically applied to the dorsal skin of C3H mouse daily for 4 weeks. Hair growth was assessed in visible changes and morphometric histology. Macroscopic observation revealed that the 5% GSLE formulation group exhibited significantly delayed hair regrowth compared to the vehicle group. Immunohistochemical analysis demonstrated that the expression of TGF-β1 and TGF-β2 was significantly increased in both L-product and 5% GSLE treated groups, with the highest levels observed in the 5% GSLE group. Conversely, β-catenin expression was significantly decreased in the L-product and 5% GSLE groups, showing the greatest reduction in the 5% GSLE formulation group. These results suggest that 5% GSLE formulation may exert hair growth inhibitory effects by dual regulation: upregulation of TGF-β1, TGF-β2 pathways and suppression of Wnt/β-catenin signaling, thereby disrupting the maintenance anagen phase of hair follicle. This study provides scientific evidence for the mechanism of GSLE in hair growth inhibition and offers a potential foundation for the development of hair growth inhibitors from natural source.