Hair biology and minoxidil:
Minoxidil stimulates hair regrowth. Vasodilatation and increased blood flow to the dermal papilla, or possible local irritation related to minoxidil or to one or more components of the vehicle used for topical application have been suggested ha mechanisms of action.. Direct drug effects include on the dermal papilla or hair matrix cells or possibly both. Biopsies in androgenetic alopecia (pattern hair loss) show miniaturization of terminal hair follicles along with Shortening and diminution of follicle, shortening of the hair regrowth cycle. The dermal papilla controls both regrowth and differentiation of hair matrix cells. The most probable site of minoxidil action in hair loss treatment is the dermal papilla.