Tom, I've tried it, not before a show, but a buddy of mine had an extra bottle left over and were were going to a pool party that day, lol, so my buddy told me to try it, he kept raving about it, so I take it, not really expecting much. I start to get a little short of breath, but nothing big, so we head out to that pool party and holy ****, it was like I had "come talk to me about bodybuilding on my forehead", lol, it got to the point that by the end of the time at that pool, if another person came up to me to tell me how peeled I was I was gonna cut them open, lol, absolutely Vascular as hell. It was pretty cool I gotta say, and lasted for 5 or 6 hours. 2 Big thumbs up from me.
But, like one guy in this thread said, I wouldn't use anything you're not used to as you never know how YOU are gonna respond to it. That is good advice from that guy.