I'm 25 right now with 26 approaching fast and have been losing my hair since around 18. I tried rogaine by itself by just applying it to the crown like they recommend. I did not see any improvements or slow down in my hair loss.
After speaking with 2 HT doctors, they told me to apply rogaine to my whole scalp twice a day, not just the crown. I am doing this as well as taking procerin. I've been doing this now since thanksgiving (around 3 months now) and have noticed my hair actually filling in and it now definitely seems thicker then it was before I started.
I really wanted to use propecia with rogaine, but after being on propecia I had very sever sexual side effects that made me stop after a month. I'm still thinking about getting a HT sometime within the next year, but have been researching like crazy to make sure that is something I definitely want to do.