Diagnostic Blood Test: DHEA, Serum DHEA is the master sex hormone necessary for libido, energy levels, and immune function. It’s the body’s natural counterbalance to stress hormones like cortisol. Sufficient levels of DHEA are associated with improved cardiovascular health, reduced belly fat, a healthy metabolism, improved mood, enhanced memory, and better sleep. While DHEA-S testing provides information about overall wellness, DHEA tests reflect current stress levels.