My friend takes it, and she does get heart palpitations and she honestly looks terrible. She doesn't hang out because she feels like crap; she's pale, her blood pressure is high and she's a mess. *But* her grades are awesome, way better than mine. So when I tell her she should lay off the drugs a bit, she always says she's in control of her dosage and the results are worth it. As for me, I'm always tempted when I see her grades, but I figure I'd rather risk having to work a little harder and maybe score a little lower than have heart palpitations.