Both of these medicines have different mechanisms of action. , While Minoxidil promotes the regrowth of hair by increasing the blood flow to the scalp. , Finasteride is a DHT (dihydrotestosterone) blocker that prevents hair loss. DHT is formed from testosterone with the help of an enzyme called 5-alpha reductase, which is blocked by Finasteride. Normally, around 10% of testosterone is converted to DHT. But in some people, more DHT is formed from testosterone due to hereditary causes or other lifestyle factors such as stress, which results in hair loss. This is because high levels of DHT in the blood can shrink the hair follicles causing thinning and loss of hair.