Well I've never used a pre-workout stim b4... And I took 2 cap's today about 45 mins b4 I worked out... I think I felt a placebo effect but as far as cardio goes I still felt I had the same energy that I've always had. Next time I do cardio I'll try 4 and see what that does. However the effects I felt was I wasn't as tired as I was earlier, and it did supress my appetite in that I didn't feel like eating but when I got home and had that first bite of chicken pot pie I couldn't stop. Anyways looking forward to trying 4.