I was confronted with hairloss at the age of 16. Went to several docters and specialists and ended up by having Minoxidil prescribed which I took for years. After a few months the loss stopped and a couple of months later the hair came back.
I took it for years and it used to cost me a fortune (about 25 U$ for every three weeks.)
I have not taken it for many years now but the side effect which New End describes still remains. The Minoxidil has affected my skin which still itches quite regulary.
General notice here: I admit it is worth its money but ... take into account the irritation of the skin which you might get. If you take it a long time, that iritation might not go away that easily.