I tried this eca stack with ephedra by American weight loss group and I have to say that I experienced what eca stack really is. I recommend you to use it only for serious workouts. I felt everything, extreme energy, sweats, I was focused and it made me feel like I was an animal in the cage trying to get away. Immediately when I started working out, I felt really awesome pumps. I was super vascular and I felt a lot of energy. A+!