As shape has pointed out, GH use is a long term proposition. I recommend loading up as much as you can afford to inject for the first 12 weeks to see an obvious change in body composition. Thereafter, as little as 2iu a day seems to maintain the results. You will start to see visible results in 6 to 8 weeks.
The change in leanness was quite dramatic for me, as an older bodybuilder.
For best results, stack with insulin, testosterone, and dbol or anavar.