Cellular energy co-factors that decline with age — widely studied for metabolic health and longevity.
NAD+ (nicotinamide adenine dinucleotide) is a coenzyme found in every living cell, essential for energy production (ATP synthesis), DNA repair (via sirtuins and PARP enzymes), and regulation of circadian rhythms. NAD+ levels decline significantly with age — by 50% or more by age 50 — correlating with many age-related metabolic changes.
Rather than administering NAD+ directly (which has poor bioavailability), clinicians use NAD+ precursors: NMN (nicotinamide mononucleotide) and NR (nicotinamide riboside), which are converted to NAD+ inside cells. IV NAD+ infusions directly raise blood NAD+ levels. NMN is also available as injectable formulations from compounding pharmacies.
The scientific rationale for NAD+ supplementation is supported by David Sinclair's research at Harvard and multiple longevity labs. However, translating compelling animal data to meaningful human benefits remains an active area of investigation. NMN was briefly a gray area between food supplement and drug before FDA intervention in 2023, clarifying that NMN requires investigation as a drug if making health claims.
Human clinical trials have established safety and ability to raise NAD+ levels. Studies in older adults show improved muscle function, cognitive performance metrics, and metabolic markers with NMN or NR supplementation. The ENERGY trial and studies from the Sinclair lab have generated substantial data, though effect sizes in humans are modest compared to animal studies.
IV NAD+ protocols have been used in addiction medicine for decades and more recently in anti-aging and performance contexts. Rapid IV infusion can cause significant side effects. Injectable NMN offers a middle ground. The evidence for dramatic longevity effects in humans remains preliminary.
📚 Key Reference: PMID: 32231347 (NMN human study), PMID: 30415938 (NR muscle function)
Oral NMN and NR are generally well-tolerated at supplement doses. Skin flushing can occur (niacin-like effect). IV NAD+ infusions can cause chest tightness, shortness of breath, and nausea at rapid infusion rates — slower infusion reduces these effects. IV NAD+ should be administered in a clinical setting with monitoring. Quality of oral supplements varies widely — third-party testing is important.
NMN and NR are sold as dietary supplements. The FDA issued guidance in 2022-2023 indicating NMN cannot be marketed as a dietary supplement because it was first investigated as a drug — regulatory status evolving. IV NAD+ is used clinically. Injectable NMN is available through compounding pharmacies. No FDA drug approval for any form.