DHEA is made from another steroid hormone, pregnenolone, which is made out of cholesterol. In humans, DHEA is the second most common steroid after its sulfate ester, DHEA-S. Rather than DHEA levels, blood tests usually measure DHEA-S levels, which are about a hundred times higher and fluctuate less during the day.
DHEA production decreases with age. People in their 70s have less than 20% of the peak DHEA-S levels of young adults. In men and women who don’t produce enough DHEA (older people, usually), supplemental DHEA can raise androgen and estrogen levels (rarely above the normal range). It can also reduce the risk of colon cancerPMD:10815698 and improve body composition, bone health, cardiovascular health, insulin sensitivity, and mood.
DHEA seems to be well tolerated, but in postmenauposal women, rare acne and rarer facial growth have been reported.
DHEA serves to make other hormones, notably the sex hormones, androgens and estrogens. It can also affect the body directly (e.g., it can weakly stimulate androgen and estrogen receptors).