Minoxidil

Etki Mekanizması

Minoxidil is a potassium channel opener that acts on ATP-sensitive potassium channels in vascular smooth muscle cells, causing vasodilation. When applied topically or taken orally, it is converted to its active metabolite minoxidil sulfate by the enzyme sulfotransferase (SULT1A1) in hair follicle outer root sheath cells. The sulfated form opens potassium channels in dermal papilla cells and vascular smooth muscle surrounding hair follicles, increasing local blood flow and nutrient delivery. Beyond vasodilation, minoxidil upregulates vascular endothelial growth factor (VEGF) expression, extends the anagen (growth) phase of the hair cycle, increases follicle size, and stimulates the transition of resting follicles from telogen into anagen. It also has anti-fibrotic properties that may benefit the perifollicular environment. Notably, minoxidil's hair growth effects are androgen-independent, making it effective regardless of DHT levels and complementary to 5-alpha reductase inhibitors like finasteride.