NAD+ explained: what it does, injections vs precursors and what human studies show
NAD+ is a coenzyme central to cell energy. Here is what the human evidence says about NAD+ infusions, NMN and NR, and which claims are still unproven.
What NAD+ is
Nicotinamide adenine dinucleotide (NAD+) is a coenzyme found in every living cell. It carries electrons in the reactions that turn food into usable energy and is consumed by enzymes involved in DNA repair and cell signalling, such as sirtuins and PARPs.
Strictly speaking, NAD+ is not a peptide; it is a dinucleotide. It is often sold and discussed alongside peptides because of its use in longevity and wellness settings.
Why NAD+ is linked to ageing
Animal studies have shown that NAD+ levels decline in several tissues with age, and that raising NAD+ can improve some markers of metabolic health in rodents. These findings drove interest in NAD+ supplementation for people.
Raising a blood marker is not the same as slowing ageing. Human trials so far measure NAD+ levels, safety and selected biomarkers rather than lifespan or disease outcomes.
Precursors: NMN and NR
Oral supplements usually provide precursors rather than NAD+ itself, because the body converts them into NAD+. The two most studied are nicotinamide mononucleotide (NMN) and nicotinamide riboside (NR).
A 60-day randomized, double-blind, placebo-controlled trial in healthy middle-aged adults, published in GeroScience in 2023, found that oral NMN increased blood NAD concentrations and was well tolerated. Effects on functional outcomes were modest and need confirmation in larger, independent trials.
What we know about NAD+ infusions
Intravenous NAD+ is offered in wellness clinics, but controlled human data are limited. A 2019 pilot study in Frontiers in Aging Neuroscience followed plasma and urine NAD+ metabolites during a six-hour infusion and found that NAD+ was rapidly removed from plasma during the first two hours, with no adverse events observed at that infusion rate.
One small pilot cannot establish safety for other doses, infusion speeds or products. The evidence for health benefits of NAD+ injections or infusions remains preliminary.
Regulatory status
NAD+ is not an approved medicine for ageing or any general wellness indication. Precursors such as NR and NMN are sold as food supplements in some markets, with rules that differ by country; NMN's supplement status has been contested by regulators in some jurisdictions.
When reading NAD+ claims, check whether the product is a supplement, a compounded preparation or research material, because the quality and legal requirements differ for each.
Frequently asked questions
What are the proven benefits of NAD+?
Human trials show that precursors such as NMN can raise blood NAD+ and are generally well tolerated. Benefits for ageing or disease are not yet proven.
Is NAD+ a peptide?
No. NAD+ is a dinucleotide coenzyme, although it is often discussed alongside peptides.
Are NAD+ injections better than supplements?
There are no robust head-to-head trials showing better outcomes with injections or infusions. Evidence for both routes is preliminary.
Sources
- Yi L et al. Efficacy and safety of NMN supplementation in healthy middle-aged adults. GeroScience 2023 (PMC)
- Grant R et al. Changes in the Human Plasma and Urine NAD+ Metabolome During a 6 Hour Intravenous Infusion of NAD+. Front Aging Neurosci 2019
- The Safety and Antiaging Effects of NMN in Human Clinical Trials: an Update (PMC)
Editorial and source policy
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