ROGAINE AFTER 12 HOURS REDDIT - DOES IT WORK?

Yo dudes, so I'm thinking on using Rogaine. Heard some talk about it helping after just a couple hours, but that seems kinda wild, right? Anyone else try this magic potion and actually see something in that time frame? Hit me up with your thoughts. Here's a few things I'm wondering: How much Rogaine do you gotta use? Should apply it to dry hair