Found this doing a search...
I've lately come more to the conclusion that I've suspected from the beginning of researching on adrenal fatigue, that supplementing with DHEA, will help low DHEA levels but usually doesn't help with low cortisol. Maybe in some patients it does help to raise cortisol, once the circle of conversion goes completely around but there's conflicting info about DHEA out there. What will help the adrenals to produce more cortisol, are vitamins that support adrenal function, rest and adequate sleep and if needed, the safe and cautious use of licorice extract and adrenal glandular extracts. Some Doctors also sometimes prescribe; pregnenolone to adrenal fatigue patients or other combinations of hormones. A lot of medical resources say that the majority of women can safely take 25mg or less of DHEA and there is very low risk of it causing their androgen levels (male hormones) to go too high and men are supposed to be able to take up to 50mg safely. I don't feel DHEA would suppress cortisol to a significant degree at these doses but the point is that they also might not help raise cortisol, so that taking it alone, could cause more of a DHEA to cortisol ratio imbalance. This isn't true of people who have low DHEA but normal cortisol levels because DHEA is all they need in these cases. The Journal of Pharmacology has a research article that states that patients with Crohn's Disease and Lupus, are one example of low DHEA, that when supplemented, improves symptoms of these diseases but DHEA can become low for other reasons as well.