It works by increasing blood flow to the area that you apply the medicine to. As the blood flow increases it slowly starts to simulate hair growth in previously dormant hair follicles, but it’s a slow process. At about 3 months I started to notice new small fine new hairs coming in. At 6 months those small hairs had grown into longer, larger hairs, and at the same time new small fine hairs were forming underneath them. At a year, most of the patches that had no hair in them before now have a pretty decent amount of hair and you can’t really tell they used to be completely bare. It’s a long process