"If your cortisol drops too low during the night your blood Sugar drops too. Your body compensate by releasing adrenaline as an emergency measure to mobilize more sugar. This has the effect of waking you in an instant. This can be reduced by eating high protein snack before retiring e.g. sardines, nuts of high quality protein shake.
In early stages of adrenal fatigue cortisol levels tend to rise and if they are high at midnight they can energise you and keep you awake. Phosphorylated serine can be used to lower cortisol at these times due to its ACTH dampening effect."