I recently started a experiment with 25 mg oral DHEA daily to try to boost my low levels (108 mcg/dl DHEAS). As of this writing, I’ve only been taking DHEA for about three weeks to a month, but I would definitely call it a success. It seemed to lower anxiety and produce a relaxing effect, which is fairly common with oral DHEA at reasonable dosages (in low DHEA men). However, I was concerned, because I had read that DHEA can raise IGF-1 levels. I had a high PSA read at one time and did not want to take any chances, since elevated IGF-1 levels are a known risk factor for certain types of cancer. Furthermore, lowering IGF-1 is actually a strong anti-aging strategy that has considerable research behind it. (Of course, you don’t want be too low in IGF-1 either.) In other words, boosting IGF-1 was not something I was interested in doing, especially at age 55.
I decided to do a little digging, because I knew that often very large dosages of DHEA are given and studies on men are less common. Basically, I was wondering how applicable the research was. And I was also only interested in the effect from physiological dosages of DHEA, i.e. dosages of DHEA that would not boost DHEA-S levels beyond normal youthful levels. For the typical middle-aged or senior man, this will be in the 25-50 mg per day range, but it is important to do blood draws before and after.
What I found was that at these kind of lower DHEA dosages, the effect on IGF-1 was fairly small more than likely. Below is a summary of the resarch that I came across:
1. 50 mg Daily in Middle-Aged and Senior Men. A study using a 50 mg dose in healthy men aged 40-70 for 3 months resulted in the following:
“Although 24-h GH pulse parameters and IGF binding protein-3 (IGFBP-3) levels were unchanged, serum IGF-1 levels increased by 10% and IGFBP-1 levels decreased by 20%, resulting in a significant increase in the IGF-1/IGFBP-1 ratio. These changes were accompanied by an improvement in perceived physical and psychological well-being for both men and women without discernible changes in serum lipid profiles, insulin sensitivity or percentage body fat.” 
The decreased IGFBP-1 levels basically mean that IGF-1 was more bioavailable. Again, I was taking half of this amount.of DHEA, so I would expect the change to be even less for me. And, if you read the next study, you’ll see the IGFBP-1 did not change with an even great dose of DHEA, calling into question that aspect of the chnage.
2. 100 mg Daily in Early Senior-Aged Men. A followup study with a 100 mg daily dose in men 55-70 resulted in a slightly greater change in IGF-1 (16%), but this time no significant change in IGFBP-1.  Of some concern is the fact that both of the studies had the same lead author. Of course, the most important thing is to take your IGF-1 measurement before and after supplementaiton and verify your own personal results. Studies just deal in averages and so it is good to confirm with your own labwork anyway. Please note that I do would not take 100 mg daily anyway: this is going to be a non-physiological dose for most men.
CONCLUSION: My conclusion is that 25 mg per day as I am doing is probably a fairly prudent and non-aggressive protocol. Assuming linearity, then IGF-1 would increase on average by only 5%. This seemis like an acceptable risk for me considering that oral DHEA lowers anxiety for me from what I can tell.
It should also be pointed out that DHEA has been found in many animal studies to be cancer protective. An example of this, and one that is near and dear to my heart, is a study looking at DHEA levels in prostate cancer-free men with and found that “although mean levels of DHEA were 11% lower among cases than controls and DHEA-S levels were 12% lower than among controls, no dose-response association was noted for either DHEA or DHEA-S. It seems unlikely that serum levels of DHEA or DHEA-S are important risk factors for prostate cancer.”  If this is true, then the primary argument against raising IGF-1 levels with DHEA is anti-aging.
CAUTION: Always talk to your doctor first before taking any supplement if you have any medical condition or are on any medications.
1) Metabolism Clinical and Experimental, 2006, 55:858-870, “Endocrine effects of oral dehydroepiandrosterone in men with HIV infection: a prospective, randomized, double-blind, placedbo-controlled trial”
3) J Clin Endocrinol Metab, 1994 Jun, 78(6):1360-7, “Effects of replacement dose of dehydroepiandrosterone in men and women of advancing age”
4) Clin Endocrinology, 1998, 49:421-432, “The effect of six months treatment with a 100 mg daily dose of dehydroepiandrosterone (DHEA) on circulating sex steroids, body composition and muscle strength in age advanced men and women”
5) Cancer Epidemiol Biomarkers Prev, 1993 May-Jun, 2(3):219-21, “The relationship of serum dehydroepiandrosterone and its sulfate to subsequent cancer of the prostate”