It seems my replies are getting lost. I will try again.
Probably better to take oral supplements that can promote body's own production of GH than directly inject synthesized chemicals. However the downside may be that some oral supplements are useless, and some may contain harmful ingredients.
The above says that GH is increased with exercise but it drops later so the overall daily production stays the same. Unless you exercise multiple times a day, which I presume means multiple 45 minute sessions rather than one.
And the above says that GABA helps promote GH production.
What I have so far is the above, multiple training sessions per day and GABA supplements.