remem u have to experiement....
start low then see how it worx, like most things in life including foods and other things do not just take a bunch. Start slow and low then see and monitor how it worx, little or no change, well then up the anty. But anything that involves the heart and palpitations be CAREFUL. I remem once taking the old speed stack and after a great workout I felt my heart go off cycle once and it is freaky. Some are super sensitive to caffiene, some ephedra, some the new stuff. Be careful when it comes to that and start light and slow then build up the process. What worx with well with some sux for others, that is where u need to experiment and see how it worx for u.
gooey