NAD is a coenzyme found in all cells. And coenzymes function as catalysts to mediate metabolic reactions.
For some great detail on the function of NAD+ within the body’s energy pathways, visit the linked caption above.
Generally speaking, NAD shuttles electrons or energy “as a way to carry stored energy to produce ATP.”
So, this is another molecule related to optimal mitochondrial health and function.
Regarding Supplementation, any beneficial substance like this is going to work better in conjunction with regular physical activity or exercise, and a nutrient dense diet.
The following foods supposedly enhance NAD: Whole grains, Milk, Fish, Yeast, Green Vegetables, Mushrooms. https://thebiostation.com/bioblog/what-is-nad-and-how-can-i-increase-it/ It should also be noted: Mushrooms come up repeatedly in my search results on longevity related compounds!
My personal experience [as a masters weightlifter turning 40 next year] with the NAD+ supplement is that it puts more pep in my step on a deeper feeling level. I cut open the capsule, since I find cellulose annoying to digest, and put it in a shake or coffee. For me, I feel the effect pretty much immediately, like I could go jogging. Pleasant, not at all intense.
This is not something I take every day, just occasionally around my weightlifting and recovery. Since naturally produced by the body, NAD+ has been NSF sport certified. However it has not been approved in supplement form yet by the FDA, to my knowledge.
Again, it’s also important to bolster the food nutrients, exercise and sleep.