Rhodiola rosea had an immediately noticeable effect on my energy levels.
I also take NT Factor which according to their quote:
"is a proprietary blend of phospholipids and glycolipids whose mechanism of action is to repair cellular membranes by increasing cell membrane fluidity. By repairing the membranes of the mitochondria (the energy furnaces within our cells), we allow all of our cells to increase their nutrient uptake so that the mitochondria may product more ATP --- the body's energy fuel."
It wasn't an immediate boost like Rhodiola but it apparently has a loading period over a month. It was also created by Dr Garth Nicolson who is pretty legit - Nobel prize nominee./www.youtube.com/watch?v=zfTcuwXGuto
My energy is pretty good these days.