I used this for energy during my mtn. bike rides and I have definitally noticed a difference. I have a more keen "drive" during those bitchin hills and my energy level stays consistent a little longer then normal.. However I used this just for one groggy morning for a little pep and didn't get much from it.. I like this product, used during taxing cardio it seems to make a difference, not to mention I dont get the jitters like Idid from a typical ECA |