^ Seeing your experience brettshk, it made me take notice as some of my experience as of late is so opposite yours. Headaches, well, I used to have them a lot when I was young. Now, the ONLY reasons I get one nowadays is either a good knock on the noggin (bang my head on something), or too much alcohol. I'd look into that, it's not right at your age, maybe to do with your dieting?
My weight was 160 in Jan, 150 in Jun, and then it seemed to stay there no matter what I did. I was 147 when 30yrs old, so I thought that wasn't awful at 69. But body shape changes with age, and I wanted to get rid of some stomach fat that didn't budge even losing 10 lbs. But I was stuck. Then started taking NMN, and since July, and mostly with higher NN intake, the pounds are disappearing, and I'm at 145 today, a modest miracle in my mind! The only real change has been with NMN, so maybe it's that? Hard to know.
As for energy, NMN seems to give it in spades, both for exercise, and things like not even thinking about afternoon naps much any more. I just have energy to spare. I do try to get 8 hrs sleep, and am more and more a flexitarian (mostly veges, chicken, and some fish). IOW, lots of protein, some carbs and good fat, and a healthy dose of dark chocolate every day.
Everyone is different, but if something doesn't work for you as you want... I would stop and consider what going wrong and try something new.