I am 20 on GH. Two months is completely worthless. I am 4 months in and I am starting to notice a considerable difference. I haven't gained any weight since I went off four weeks ago but I kept all I gained and overall I look a lot different. I would do it for six months at the least.
From what advice I was always told is that 30 yrs old is a guide as to when you should start with GH . ANd then only if you have gained all that you can by other means. IMO