I've done IGF-1 at 40mcg every training day. It did make me feel lethargic, interestingly that was the kind of lethargy that I simply couldn't shake, but nothing too bad. I tried training at night and do the IGF when I have nothing left important to do in my day, it was perfect that way. Made me sleep like a baby. I think I remember having a trace of headache the first day or two, nothing too important, and it was soon gone.
Moreover, I need to state that now, 6 months after taking IGF-1 as my ONLY exogenous hormonal growth enhancer EVER, I have retained 100% of gains. It is amazing stuff, definitely recommended and totally worth the sides. Remember, it will grow NEW CELLS that you keep FOREVER. It also makes your next gear cycle better. Go for it, dude.