Adrenal fatigue can cause improper cortisol regulation - Phosphatidyl Serine, when given at the correct time of day, can help alleviate high night-time cortisol level. High midnight cortisol levels denote stress maladaptation - the loss of the negative feedback inhibition whereby the brain and pituitary gland down-regulate inappropriately elevated cortisol.

Cortisol levels are supposed to decline through the day, and be lowest at midnight.

"When midnight cortisol levels are elevated, supplementation of an additional nutrient is indicated. High midnight cortisol levels denote stress maladaptation - the loss of the negative feedback inhibition whereby the brain and pituitary gland down-regulate inappropriately elevated cortisol. Supplements of phosphatidylserine have been found to result in reduction of midnight cortisol levels. Incorporation of phosphatidylserine into the membranes of brain cells apparently restores sensitivity to cortisol receptors."

Source:
http://digitalnaturopath.com/cond/C17649.html
http://digitalnaturopath.com/treat/T189033.html