6 months would be the minimum to run gh at... anything less and ur just wasting your money. And 5days per week, last time I checked there's 7 days in a week bro
4iu will do very little as far as fat loss, and won't do a thing as far as muscle growth.. the only other benefits of such a low dosage would be improved sleep and skin will get tighter. If u want the gh to help u with bodybuilding goals then ur gonna have to commit to running minimum 8 iu's EVERYDAY, for years, not months.
my advice would be to wait til you've reached a level with your physique that u NEED it... but if ur currently walking around at 5'10 250 and 10% then ur good to go... but if ur more like 180, then i'd suggest just running gear, eat a shit load and train, train train