This producrt works Great for me becuase during my workouts i like to have energy and get hyped, but i dont like the jitters. Only con with effectivness is that if you don't drink it right on time like the directions say, it doesn't last the entire workout. The taste is kinda bad but if you mix it with blue Gatorade or powerade it taste great. It's a little pricy but can be worth the price. Deffinatly worth a try. try cycling off every 4th week. That will help increase the effectivness.