The problem is that taking more in one dose isn't going to work much better you have to spread it out through the day. Too much at once pushes toward anxiety and jittery but a nice even spread thought the day is going to work better. So bascially you need to replace it once your body metabolizes it away but at baseline you only need so much to get an adrenaline boost. You can actually get the same effect from exercise as well. Think of it like tylenol or advil if you have 4 extra strength pills at once you can end up killing your liver but if you dose those same 4 pills evenly thought the day you stop a headache for the whole day. Past a certain point pain killers don't become more effective they just become more toxic...same with caffeine.