OK --first thing first
etiology of hair loss may be-genetic,infection,pollution,stress,Poor nutrition,Hormonal changes or idiopathic--
use good anti dandruff shampoo don't buy clinic all clear stuff--
go for medicative shampoo--one with ketroconazole and selenium.
2nd thing you can use minoxidil--but it would show its action only after 6 months-
it basically increases the blood supply to your hair root. and it would slightly affect your sex which i think may be concern for you--
-------topical minoxidil, systemic finasteride 1 mg tablet per day
finasteride --here the side effects is that you may see hairs on unwanted areas
but hair loss aint simple problem--you would need to see a doctor before taking medicine-
general measures--avoid smoking,take nutritious food,and pay homage to salman and himesh
if you are interested i can give you exact doses and all side effect--i have to look my books