You may have heard of so called ‘NAD boosters,’ compounds that you can easily buy online like nicotinamide riboside (NR) and others. There’s even a high profile company offering monthly subscriptions to supplements including NR that may boost your NAD levels. It makes sense: NAD levels decline as we age, and giving NAD boosting molecules like NR (which is just a metabolite precursor to NAD) can improve health parameters and extend lifespan in mice1–3.
What’s it going to do in humans?
Basically, more studies are needed, but here’s a clinical trial in humans (NCT02835664) that found that after 6-weeks of supplementation of NR, there were no effects on insulin sensitivity, mitochondrial function, hepatic and intramyocellular lipid accumulation, cardiac energy status, cardiac ejection fraction, ambulatory blood pressure, plasma markers of inflammation, or energy metabolism4. Mind you, usually treatments in mice are for longer on a relative scale, so treatment periods of years for humans may be needed to see an effect at all.
So, do I take it myself? No. But I also don’t think that I belong to a group that would really benefit from it, I’m in my 30s, non-sedentary, non-obese, and non-diabetic. Perhaps a more relevant question is, would I recommend it to my parents? They are like me, but just older, and NR should be something to help with aging, right? Well, when intervening in your biology, there’s always a risk assessment needed, a cost-benefit analysis. What are the odds that it does anything helpful for me, and is that worth it, considering the odds that it might harm me? One of the most detailed risk assessments I’ve seen about NAD boosting you can find from the Forever Healthy foundation. Personally, and especially when considering family and loved ones, I prefer to err on the side of caution.
The bottom line is that we just need more studies in humans. Though not too many tissues have been described to have NAD levels decline in human aging yet5,6, I’d still bet that people who are ‘biologically younger’ for their (chronological) age will have higher NAD levels. Whether that’s a cause or a consequence of other aging processes (e.g. see article 7), and how to achieve higher NAD levels effectively and safely, are open questions.