I've used 500 mgs/day-yes 500 mgs-not a typo-but I was crazy and young-that's 10- 25mg pills pre workout AM and 10- 25mg pills pre workout PM. These days I use 50 mgs pre workout AM and 50 mgs pre workout PM. 100mgs/day total. Any more than that and I get headaches. It sucks getting old. Also eph was way cheaper back then. I'd buy 3 bottles of 1000 25 mg pills for about the cost of 2 new release DVD's-shipping incl.