I had this stuff sitting on the shelf for about a month after I ordered it and before I went to work last night (I was dead tired) I needed a pick me up...so what the hell I downed 2 of the pills with some water before leaving. Wow...I have never really been effected by caffiene before this, I mean seriously I can down a coffee with 4 shots of expresso and go to bed an hour later. I was shaking though and felt like I could run a couple hundred miles. It lasted a good two hours before it wore off. Pretty cool supplement... 
