Honestly the only things that work are finasteride and minoxidil. You also have other drugs like CB and RU but those are basically chemicals you have to source form China yourself. A large number of people will say take finasteride and you'll be fine, but just know that it comes with pretty awful side effects. Some people dont get them, some people do. I am having to taper off of finasteride at the moment after being on for 5 months.
You've also got Trinov which has recently been released although its still too early for any of us to truly know if it does anything, so i would suggest you follow in the research section yourself.
Sorry man i know its tough especially at your age. Im 24 now and it can be pretty depressing.
Hi, im also 19 and since i was 17 i started losing my hair. I recommend you go to a dernatologist so he can help you and guide you. Sorry for bad english(im from México)