I bought this bottle last week, and tried it twice.
The first dose was on wednesday while i was at school, at around 10 45am on a fairly empty stomach (2 pills). Around 20 minutes later i had a small bite to eat, then was in gym to do my regular shoulder workout. Noticed an increase in focus and intensity which resulted in taking less time to between sets. The energy increase lasted for another two hours give or take after my workout, and helped my focus while studying, shortly thereafter for a physics test.
It was friday, first football game of the season and decided to up the dosage to 3 pills, and see its effects could withstand a whole football game. The AMP definately kicked in before kickoff, and stayed with me throughout the game, very energy without the jitters, and great mental focus.
This product is definately a great pre-workout energizer, worth the money imo.