There are clearly some significant misconceptions about the hormonal changes that DHEA supplementation actually brings about. The common wisdom out there is that DHEA can “choose a pathway,” either testosterone and estradiol and you never know which one it will be. Some men will get a boost in testosterone and some men will get a boost in estradiol. Now there aren’t a lot of studies on DHEA and hormones in men, but, after I discuss the research, I think that you will agree with me that the above testosterone-or-estradiol-pathway theory is simply not true. Yes, occasionally a man may get a small boost in estradiol, but this is the uncommon exception.
So am I saying that DHEA does nothing? Actually, I am saying the opposite: DHEA does profoundly affect certain hormones – just not the ones that most men think about. Let’s start with a study where they gave HIV-positive men a large dose of DHEA (usually 400 mg / day) and monitored the key hormonal changes that occured:
Hormones That Did NOT Change:
1. Total Testosterone. This did not change at all from week 1 to week 8 (600 ng/dl). This has been echoed in a couple of other studies: DHEA simply does not change total testosterone significantly with either moderate or, as in this case, massive doses. Need one more example? Here are couple of more:
a) 50 mg in Men Aged 40-70. According to this study, some change in IGF-1 occurred, but none in testosterone.  This dosage is kind of the standard dosage that I see most men taking on The Peak Testosterone Forum with 25-100 mg being the range.
b) 100 mg in Men Aged 55-70. A followup study by the lead author of the above study for a longer period (6 months) and double the dose again found no difference in testosterone (or DHT) in men. 
CAUTION: In my opinion, no one should consider taking DHEA without first testing to see if he is low. For labs that will do this reasonably, see my page Testosterone Labs. I always recommend working with a doctor, naturopath, or an organization like Life Extension Foundation if you are dealing with hormones to make sure adequate testing is done and that you have no contraindications. DHEA falls off with aging, so many men over 40 will have low levels of DHEA
2. Estradiol. This changed minimally from 37 pg/ml to 35 from week 1 to week 8. This is less than a 10% change and probably within the lab error range. Notice, by the way, that not only did estradiol not increase, it dropped! The second study mentioned in #1 also found no change in estradiol with a 100 mg daily dose.  Again, I know of no evidence that DHEA increases estradiol in most men. If you want to play it safe, you can test before and after. See my page Which Estradiol Test is Best? for more information.
3. Cortisol. DHEA has a yin and yang relationship with cortisol, so, obviously, giving this large of a DHEA lowered cortisol significantly right? Again, the answer is ‘no:’ 14 ug/dl before and 13 after, again less than 10% change.
So the hormones that were supposed to be flying into orbit or imploding scarcely budged. Yes, you have to watch out for that “bro science.”
Hormones That DID Change:
Clearly, though, DHEA is affecting something right? As I describe in my page on The Benefits of DHEA, it has likely restored morning erections in a couple of our posters at relatively small doses. Keep in mind that the study was using LARGE doses of DHEA (400 mg) that should be taken by most men and so the hormonal changes are likely MUCH larger than one would achieve at smaller doses.
To give you an idea, post-supplementation plasma DHEA-S levels went from 875 to 17,775 ng/ml. Most low DHEA men are in the 100-250 range and the usual target with normal DHEA supplementation is 350 to 500 from what I have seen. So these men actually had respectable DHEA levels and supplementation sent them through the roof. But this is an important study, because it shows what hormones actually can be altered through with DHEA usage:
So let’s look at just what hormones were changed by DHEA.
1. Free Testosterone. This rose significantly just as expected from 17 to 29 pg/ml from weeks 1 to 8. I say expected, because there is a well-known study out there that echoes these results. In fact, this study showed that, when combined with HIIT, it doubled free testosterone levels. See my page on How to Increase your Testosterone Levels Naturally for the specific study involved.
2. SHBG. It is no secret that DHEA drops SHBG, but what is not as well known is that it does not lower it by all that much. In this study, and keep in mind that this with a large dose, SHBG only dropped from 55 to 49 nmol/l from weeks 1 to 8. This is just a little over 10%. Nevertheless, it did go down as expected.
3. DHT. Dihydrotestosterone (DHT) is a major male androgen that has significant effects on libido. It can also negatively impact the prostate and the hair line in some sensitive men. In this study DHT jumped from 640 to 3,392 pg/ml from week 1 to 8. (Remember this was with a very large dose of DHEA.)
4. Estrone. This estrogen tripled from 163 to 498 pg/ml from weeks 1 to 8. Of course, this is odd, because estradiol scarely changed, but this estrogen changed dramatically. This estrogen is much less studied in men. If you are diabetic, it may not be good to increase your estrone for example. 
5. Androstenedione. This skyrocketed from 2 to 13 ng/ml from weeks 1 to 8.
6. IGF-1. A few studies show changes in IGF-1, which is potentially dangerous, although I would argue that the changes are pretty small for lower dosage. See my page on DHEA and IGF-1 for more information.
The DHT may scare some of you. Again, keep in mind that most men are taking much smaller doses that these HIV men, who have a clinical need for higher doses of DHEA. The typical doses for us guys that I see out there are either 25 mg or 50 mg daily. The former is 1/16th of the typical dose in this study. So I recommend monitoring before and after with one of these Testosterone Labs.
Notice the profound hormonal changes that occur from week 1 to week 8. Several men on the Peak Testosterone Forum have successfully, tried DHEA supplements only to find that the effect fades after a few weeks. Could this be the reason? (There are also transdermal / topical DHEA products out there as well now and these bypass the liver. Some men do better on these.)