We used to give Christian his in the evening.. main reason was because my husband is a nurse and works nights and when he left for work, he would give it to him as he would not be there in the morning when I would have to take him to daycare.
Nicholas has been on growth hormone for almost four months. I give him the shot at about 8:30 every night. It was recommended by the nurse to do it at night (maybe because kids grow during the night). Not sure if she is right or not - but it works for us. I don't know how much (if any) Nicholas has grown - it's hard to tell. We have follow up in October with Dr. Rutter (but we get the hgh through our insurance here in California). He is almost 14 - I don't know if that makes a difference in the effectiveness of it either. Anything is better than nothing at this point - he is only 48" tall and hasn't grown in years. Good luck :)