I took 1 t-rex on day one and felt nothing. Took 2 the next day and felt like I drank a pot of coffee. I even took it on an empty stomach and was fine. 3rd day same thing, like a pot of coffee. After that the feeling has subsided. It's been a few weeks now so I'm going to try and up it to 2 in the morning and 2 in the afternoon. Body fat has dropped 2 % but that could be due to the added cardio. I will also keep the updates coming.