I took 3 at once one time and two more a few hours later, and i didn't sleep for 2 days, I almost had a heart attack. These things mess with your system a lot. A lot of people I know took these in school all the time, you do get quite a buzz from these things, but they're just horrible. I know a girl that got addicted to these things, she lost a lot of weight and stayed that way, just skinny as hell. Just be carefull with these shitty things.