I've tried doing the whole vial all at once everyday, and splitting the vial up into 2-3 doses throughout the day. I seemed to grow better on the one big dose (especially when I ate most of my calories as the GH was peaking... Not so much when dosing at night and it was peaking during sleep with no food being eaten while it peaks), but fat loss seemed a bit smoother when I split it up throughout the day. Though I have a feeling, and this is probably stupid, but I don't feel like 1-2iu in a single injection would do much for me. Afterall I think thats basically what the body already produces on its own, isn't it? At least, for us younger guys. Older guys may benefit more from the lower dose since, as i understand it, they don't produce much of their own.