the DHEA thing got pushed during the 2000s by supplement guys like Ross Erstling pretty hard. I love Ross but the guy had a supplement company that sold it.
it is another useless supplement pushed by companies
if you want to prevent lethargy on cycle run conservative amounts, and make sure you go into every cycle in top shape. if you cannot run a mile in under 8 minutes then your conditioning sucks. so of course hopping on gear you will feel like shit