Dihydrotestosterone (DHT) is widely accepted as the as the main cause of male pattern baldness.
DHT is produced when the enzyme 5 alpha reductase combines with testosterone.
DHT then attaches itself to the hair follicle shrinking them, making them progressively smaller.
Over time the follicles produce thinner and thinner hairs and they grow for a shorter time than normal.
Eventually the follicle ceases to produce hair, leaving the area bald.
By inhibiting DHT production the hair follicle is allowed to grow normally and produce thick healthy hair.