I used these while on Tren ace to help get through cardio. I took one amp about 30 minutes to an hour before cardio. They gave me a really good,clean energy and focus. I hate cardio, especially on Tren but these had me going strong. Each time I used them I easily knocked out an hour on the elliptical or stairs and still felt my lifts were not hampered TOO much by that amount of cardio. They gave me crazy sweats but that I'm sure is them Combined with Tren. Even after that and weights, I felt like I could go home and get my honey-do list taken care of. I definitely need more of these for next Tren run.