DHEA is very confusing. No one quite understands everything it does.
I'm going to have a go at a better explanation. This ain't free of error. Where the errors are and where the truth is and what proportion of each is herein .... I haven't a clue but here goes:
DHEA blocks cortisol but gives an energy boost. It messes around with norephinephrine reuptake, I can't remember. Its a neurosteriod. I can look this up (or you can) via wiki... but I can't be bothered.
The gist is that its a bit like being on strong stims ... you're system starts shutting down cortisol. If you stop the stims you feel fatigued and thats 'cause your cortisol has taken up the slack. DHEA can cause a sort of adrenal fatigue. If you're cortisol is really high (post cycle) DHEA is useful for counteracting it (or just don't bother sleeping).
Pregnenolone is a standard supplement to kick start the adrenals back to life (adrenal fatigue), its in Reset AD, along with stuff like liquorice. Pregnenolone is also a neurosteriod - you seem to be able to take it without any adverse effects long term (unlike DHEA). I don't know why DHEA and preg. are used together in DTP and PP products, perhaps pregnenolone is off-setting the damage that DHEA could do (adrenal fatigue type damage, i.e. not serious). IMO its better to run them separately (first DHEA and then pregnenolone) but its not easy to do, 'cause most products have them in together. However if you over did it on DTP Dermacrine etc... and felt fatigued running Reset AD is the right thing to restore the system....
I dunno if that makes any sense, or exactly how acurate it is, but off the top off my head thats as good as I can do.