4. Brain Booster. In my opinion, HRT works not because it can (sometimes) improve erectile function or restore morning erections, but instead because it is such a brain booster for hypogonadal men. For a man who has low testosterone, Testosterone Can Restore Brain Dopamine and increase brain-benefitting estradiol and DHT levels as well. Therefore, libido and mood usually increase on a well-done HRT program. Depression scores improve. And even mental performance can improve – working and verbal memory for example. Basically, this is not always the case, but usually in my opinion testosterone is a great “brain tonic” for a man that is deficient.
Now let’s go back to DHEA. Does it exert similar brain-boosting characteristics? The answer is that it probably does not for most men, simply because there are quite a few studies who found that in men no increased libido, mood or memory. (Women do a little better in the studies.) However, there was one study that found that it “was associated with a remarkable increase in perceived physical and psychological well-being for both men (67%) and women (84%).”  Unfortunately, there was no increase in libido. Like most of the studies, the participants were give 50 mg per day. The bottom line is that some men, for reasons unknown, may get a boost in well-being, mood and the like, but don’t expect it. This brain boost may be responsible for some of the good reports I am getting.
5. Sleep Aid. DHEA can lower cortisol and is considered a “stress tonic” by some. Perhaps for this reason, DHEA seems to help with sleep in the sense that it increases REM sleep.  Interestingly enough, morning erections generally occur during the REM sleep phase, so perhaps this explains why the man above enjoyed improved morning erections? (A very large dose, 500 mg, was given in this study and it was on healthy young men. So more study work needs to be done in this area.)
6. Cortisol Reduction. DHEA can lower cortisol as well in some men. Generally, this is not the case though according to a number of studies
Did you know you can inexpensively do your own testing for most hormones? The industry leader is Discounted Labs..
CAUTION: DHEA should not be given in my opinion if you are not low in DHEA. It should also not be given in higher dosages. See my page Potential DHEA Dangers for more information. While DHEA levels plummet with aging, it is important to get a DHEA read before. You can pull your DHEA inexpensively here: Testosterone Labs.
Testosterone Therapy (HRT / TRT) and DHEA
Above I documented the studies that show that DHEA does not significantly increase total testosterone on average but likely does increase free testosterone in many men. But what about the other way around? What if a man significantly boosts his testosterone through HRT (TRT)? Will that raise or lower his DHEA?
Unfortunately, my answer to that question is anecdotal: there are several knowledgeable HRT physicians who have stated that decreased DHEA is a common side effect in the medium and long term testosterone therapy. The reason given for this is that testosterone tends to shut down the body’s HPA (hypothalamus-pituitary-adrenal) axis, and the theory is that this “shutdown” can leave some men with lower DHEA.
Can I prove this or back it with some references from the medical journals? No, I cannot. However, I can tell you that my DHEA was every low after being on testosterone cypionate for a couple of years. My DHEA-S was right around 100 ug/dl last year (2014) and a typical range for a man my age would be about 109-208 (25th, 75th percentile). 
On a practical level, it would be prudent for men on TRT to measure their DHEA-S before and after TRT. For more information on DHEA, see my Index Page on DHEA.