If you have to use it stick with the herbal form Ma Haung not standardized extracts or synthetic version as I recall there are other components in the herbal form that counter the dangerous negative side effects(though not the wired feeling).It is more useful as a fat burner(speeding up metabolism)rather than an energizer and I definately would only use it with low intensity activity/exercise.I could never tolerate it on an empty stomock when it is reportedly most effective or during activity more intense than walking and use to occasionally drink it in a bodybuilding formula that contained 20 grams of whey protein and 20 grams of complex/simple carbs and viewed it as more a meal replacement when I was away from home and engaged in low intensity activity such as beach or mall.I don't miss that they no longer make the formula and have not used ma haung in a number of years.