Even if minoxidil has been known for over 30 years as "hair growth stimulator" the precise mechanism of its action is not completely elucitated. Minoxidil shortens telogen, accelerates telogen-exogen phase and causes the premature entry of resting hair follicles into anagen phase. Moreover, minoxidil increases hair follicle size. A large part of hair treatment scientific literature confirms the efficacy of topically applied minoxidil in humans. In particular, patients treated with minoxidil showed a significant increase in "non vellus" hair count starting from baseline. Preparation of minoxidil requires molecule stability and solubility. Today are available on the market minoxidil-based formulations having low-concentration of propylene glycol to obtain preparations with a better cosmetical acceptance and dermatological safety. The body of evidences indicates that minoxidil still represent a milestone in the treatment of androgenetic alopecia and that its story is going on.