NAD+ has become the most discussed molecule in longevity medicine — and for good reason. Nicotinamide adenine dinucleotide is a coenzyme present in every living cell, essential for energy metabolism, DNA repair, and the activity of sirtuins, the family of proteins most closely associated with lifespan regulation. The problem: NAD+ levels decline approximately 50% between ages 40 and 60.
The Preclinical Promise
The animal data is compelling. In mice, NAD+ repletion via precursors like NMN and NR has demonstrated improved mitochondrial function, enhanced DNA repair, reduced inflammation, and — in some studies — extended lifespan. David Sinclair's lab at Harvard showed that NMN could reverse age-related vascular dysfunction in aging mice, restoring blood vessel density to youthful levels.
But mice are not humans. And the leap from preclinical promise to clinical proof is where most longevity interventions stumble.
“The question is not whether NAD+ matters — it clearly does. The question is which delivery method, at what dose, for which patient, produces meaningful clinical outcomes.”— Dr. Elise Weber, Head of Regenerative Medicine
IV vs. Oral: The Bioavailability Question
Oral NMN and NR supplements have gained massive consumer popularity, but their bioavailability remains a subject of debate. First-pass liver metabolism significantly reduces the amount of intact NAD+ precursor reaching systemic circulation. A 2022 study in Nature Metabolism confirmed that oral NMN does raise blood NAD+ levels, but the magnitude and tissue-specific distribution vary considerably between individuals.
Intravenous NAD+ bypasses the gut entirely, delivering the molecule directly to the bloodstream. Clinical protocols typically infuse 250-750mg over 2-4 hours. While this approach is more costly and time-intensive, it achieves plasma NAD+ concentrations that oral supplementation cannot match. At AURUM, we use IV NAD+ as part of targeted protocols, not as a standalone intervention.
What the Human Trials Show
As of early 2026, several human RCTs have been completed or are underway. The VITALITY-NAD trial (n=120) showed significant improvements in walking speed and grip strength in adults over 65 receiving 600mg oral NMN daily for 60 days. A smaller trial at Washington University found that 250mg NMN daily improved insulin sensitivity in prediabetic women. IV NAD+ studies are fewer but growing — a pilot at Duke showed improved cognitive processing speed in a 10-session protocol.
The evidence base is real but still maturing. NAD+ therapy is not a miracle cure — it is one tool in a larger toolkit. The institutions that will deliver the most value are those that integrate NAD+ into comprehensive, measurement-driven protocols rather than offering it as an isolated service. That distinction matters more than most patients realize.
