How To Stop Hair Fall?

Hello sir, i m 21 years old.Upto a year ago i had long hair,but about then my hair started to fall.I didn't do anything and during my stay at pune,they fell in large chunks.Then i started an homeopathic course.It stopped falling of hair and regrew hair at front of the scalp but not sideways and behind.I am worried and want to know the possibilty of an alopathic course.Since homeopathy was largely succesful,i am confident of getting my hair back given my young age.Please give me instructions and possibilty of getitng my hair back.