If your goal is to gain muscle mass, it will help to be able to combine your GH with carbs. If you are only taking one dose, and the goal is to gain muscle, I would take it at your workout. At this point, your body is going to do a lot more to use the hormone, especially while insulin is higher, vs when you are sleeping. If your goal is HRT, then night time would be fine. Personally though, I would prefer to take a single dose, first thing in the morning for general health or fat loss. When going for fat loss, I will take GH on an empty stomach before fasted cardio. No matter what, it is still going to work.