There are so many factors that that contribute to hair loss. Hormonal inbalance, poor diet and a lot more (I won't bore you with the full list)
For me, I'm sure it was chemical related. The crown area of my head had very less hair and you could actually see my scalp playing peek-a-boo with everybody. Many people asked me why I was BALD! :O
The reason was I was doing too much to my hair. Straightening, coloring (at one time 3 times a month!). I stopped coloring my hair for about 5 months and now I've started seeing baby hairs poking up.
Tugain ~ It is basically the same as Rogain because they both contain Minoxidil.
Usage: Apply 1 ml twice a day, at 12-hour intervals, starting at the center of affected area and spread evenly with fingertips (do not massage)