Educational content only. This article is for informational purposes and does not constitute medical advice. Erica is not a physician. Always consult a qualified healthcare provider before making any health decisions.
NAD+ might be the most talked-about molecule in the longevity space right now. It's in every supplement stack, every biohacker's protocol, every longevity clinic's IV menu. But when I went through the actual peer-reviewed literature, the picture is more nuanced than the marketing suggests — and more interesting, too.
NAD+ (nicotinamide adenine dinucleotide) is a coenzyme present in every cell of your body. It plays a central role in energy metabolism — it's essential for the electron transport chain, the process by which cells generate ATP. It's also a required substrate for sirtuins (a family of proteins associated with longevity and stress resistance) and PARPs (enzymes involved in DNA repair).
The key observation driving the NAD+ longevity hypothesis: NAD+ levels decline with age. In humans, NAD+ levels in tissues appear to fall by roughly 50% between young adulthood and middle age, with continued decline thereafter. The question is whether this decline is a driver of aging or a consequence of it — and whether supplementing can meaningfully reverse it.
You can't meaningfully supplement NAD+ directly — the molecule doesn't cross cell membranes efficiently. Instead, the supplement market has focused on precursors that cells convert into NAD+:
Here's where I want to be precise, because the gap between animal data and human outcomes is significant.
In animal models, particularly mice, NAD+ precursor supplementation has produced impressive results: extended lifespan, improved metabolic function, better muscle performance, reduced neurodegeneration markers. The mechanistic case is compelling.
In humans, the trials are smaller and the outcomes more modest. What we have solid evidence for:
What we don't have solid human evidence for yet: extended lifespan, meaningful cognitive protection, reduced cancer risk, or most of the dramatic outcomes seen in mouse studies. These may come — the research is young — but anyone presenting NAD+ supplementation as proven anti-aging therapy is overstating the current evidence.
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IV NAD+ infusions have become popular at longevity clinics, typically at significant cost per session. The proposed benefit is bypassing the oral absorption and conversion process entirely.
The honest assessment: there's very limited published data on IV NAD+ specifically. Anecdotally, many people report significant energy effects during infusion — though some of this may be the experience of the infusion itself rather than a lasting metabolic change. I'd want to see more rigorous data before concluding IV delivery provides meaningful advantages over well-formulated oral precursors.
The NAD+ hypothesis is scientifically legitimate and the mechanistic rationale is strong. The animal data is compelling. The human data is early but promising in specific areas like muscle function and metabolic health.
For someone in their 40s or older interested in longevity, adding an NAD+ precursor (NMN or NR) is a reasonable, low-risk intervention with a plausible biological rationale. But go in with accurate expectations — you're not guaranteed the dramatic lifespan extensions seen in mice, and the supplement industry has gotten well ahead of the human evidence.
