I started losing at the same age, and while I do think minoxidil helps, it certainly doesnt stop it. I use spironolactone 5% once a day now.. unfortunately theres really no way of knowing if this works because you can't see an alternate version of yourself if you hadn't used it! But I do know that recently I travelled for 6 months and stopped it and when I came back my hair was very bad. Since going back on spironolactone and starting minoxidil again things have thickened up but I dont know which has helped. The problem with spironolactone is its just SO damn expensive.. a year on that stuff once a day (1/2 dose) will still cost you about $300-400 a year which is just outrageous to pay for something you dont even know is working..
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I should also add, your hair looks just about perfect so don't worry too much. As someone who has been in your exact situation, let me please impart some wisdom on you I wish someone had to me. Cherish the hair you have now, and don't worry about whatever thinning may be occuring because at your stage it is very minimal and most likely no one will even notice. Trust me. Dont let it bring you down. Love it while you've got it because in 5-10 years you'll probably be looking in the mirror and seeing a whole lot more scalp! I spent most of my time with hair worrying about it not being perfect rather than enjoying the fact I actually had it.. Its only gonna get worse so enjoy it and your youth while you can.
That said, now is also the time to seek treatment and potentially slow it down/stop it. You are the age where if you treat now, you quite possibly could never lose your hair if you keep up treatment (or by the time it gets worse in 10 years there'll probably be better treatments). So act now, just do your research into medication side effects etc.
