ROGAINE AFTER 12 HOURS REDDIT - DOES IT WORK?

Yo dudes, so I'm thinking on using Rogaine. Heard some stuff about it helping after just 12 hours, but that seems kinda sketchy, right? Anyone else try this magic potion and actually see changes in that time frame? Hit me up with your experiences. List a few things I'm curious: What much Rogaine do you gotta use? Should apply it to clean hair?