Hi all, first post here. I've searched quite a few posts on the topic of lethargy but haven't come across much that explains specifically what mechanism causes this to occur (if I've missed some obvious post please point me in the right direction). The closest thing I've found was a mention that it was due to ATP being shuttled to muscle cells rather than brain cells (when on cycle). Granted, I'm a bit older than most of the guys that post on here so maybe this is an "old guy thing"... dunno <that's why I'm posting in the 35+ forum>. Can anyone confirm or debunk the ATP-shuttling issue? It seems to me if it's an ATP issue (and assuming carbs are adequate for a cycle) then maybe adding a hefty dose of D-Ribose may lessen the effect. Any thoughts?