PDGFs stimulate the growth of dermal mesenchyme. PDGF signals are involved in both epidermis–follicle interaction and the dermal mesenchyme interaction required for hair canal formation and the growth of dermal mesenchyme, respectively 5 VEGF belongs to a family of powerful growth factors with action on mitotic cells and the endothelial cells of blood vessels, and increases vascular permeability. The hair follicle is an avascular structure, the growth of which depends on the vessels and capillaries that form the vascular plexus in the dermal papilla. Yano et al6 identified VEGF as a significant mediator of hair follicle growth and cycling, providing the first direct evidence that improved follicle vascularization promotes hair growth, as well as increasing follicle and hair size.