It was absolutely bizzarre, some days it was extremely calming i could barely lift my head, some days it would be amping me up like no end...but the THIRST was there..but if it makes you tired, I would class that as a good thing. Especially as you said you have high cortisol....invoking a parasympathetic state is always a good thing in AF?
I took D-Ribose as part of Dr Lams protocol, Dr Myhill uses it in her Chronic-Fatigue-Syndrome protocol, so must be something good in it. But its not really about what we take, its when we take it, thats the tough bit to figure out.