Many things gradually reduce natural GH release:
1) Insulin levels going up.
2) Glucose levels going up.
3) Fatty Acids levels going up.
4) Lack of exercise.
5) Increasing BMI.
6) Free radical damage of the control systems.
Restoring Melatonin levels at night will help to restore night time GH
But your Insulin and Fatty Acids levels also need to be reduced. That's
where a low carb, high protein diet with moderate exercise comes in.
Read Protein Power for a good primer.
I take by amino based GH booster mix in the morning as that is a good
time when Insulin and FFA levels are naturally low. This time is what I
call a "Growth Hormone Friendly Zone".
I believe the good GH pulse I get, helps the body to stay in a burn FFA
mode most of the day. Eating carbs for breakfast tells the body to
switch into a burn glucose mode. I prefer my body to naturally burn FFA
(this is not Ketosis) instead of Glucose.