Though this is not for everyone, I've found that taking caffeine seems to help with the "hit by a truck" feeling in the morning. I can actually take caffeine just before bed and still fall asleep (!). Per
Myhill, caffeine helps with AMP. Combined with
D-ribose for ATP, it can potentially assist with energy levels.
For some, caffeine can have unfortunate side effects. The same with d-ribose, which I would recommend taking after eating carbohydrates to avoid hypoglycemia - and I'd be careful if diabetic.
Previously, I was also taking pseudoephedrine, which I found is actually a potential medicine for POTS. I would not recommend it for anyone with higher blood pressure, or even normal blood pressure, perhaps. It can cause hypertension (high blood pressure), tachycardia (fast heartrate), and anxiety. It can help via vasoconstriction. For me, I found it about doubled what I could do in a day, perhaps by addressing blood volume/brain oxygen level issues.
If you are drinking a lot of water and taking lots of salt, it can make you feel
awful and keep you awake for the entire run of the medication. So, something to be used in very select circumstances!
If the body is attempting to repair itself and archive memories from the day during sleep, then maybe that is more energy-intensive than being awake? Just a theory.