ok, 2 methods to stop it and even to make them grow more: (no kidding)
1. start taking Zinc (u can take over-dose, no problem, it's good for man, my brother had experience of taking it, so, don't worry of side affects, bcoz, there isn't.hehe)
2. if u r not lazy enough, get ginger from the market. everyday, u cut several slices and rub them on ur scalp until the juice is absorbed.

after a month, ur problem no longer exist.
after all, better keep a good timetable for ur life. not to sleep too late. this kind of problem normally comes from the stress and disorder of hormones.