Few molecules have attracted as much attention in longevity and regenerative science over the past decade as NAD+. From academic research institutions to major clinical trials, nicotinamide adenine dinucleotide has emerged as one of the most studied compounds in the fields of cellular metabolism, ageing biology, and mitochondrial function. This post provides a research-focused overview of what NAD+ is, why it has become so central to longevity science, and what the current clinical literature tells us. All content is provided strictly for educational and research purposes only.
What Is NAD+?
Nicotinamide adenine dinucleotide — NAD+ — is an important coenzyme essential for metabolism, energy production, gene regulation, and cellular communication. MDPI
NAD+ plays a pivotal role in cellular metabolism and is a co-substrate for enzymes that play key roles in pathways that modify ageing. Metabolomics-based studies of ageing have identified NAD+ as a central metabolic intermediate linked to many of the hallmarks of ageing. PubMed Central
It exists in two forms — NAD+ (oxidised) and NADH (reduced) — and cycles between these states during cellular energy production, making it indispensable to virtually every living cell.
Why Does NAD+ Decline With Age?
Extensive research has demonstrated that NAD levels decline with age across multiple species, correlating with various hallmarks of ageing including mitochondrial dysfunction, genomic instability, and altered cellular communication. PubMed Central
NAD+ concentrations in humans may be 10% to 80% lower with advancing age. Additionally, numerous diseases are associated with reduced NAD+ levels, including metabolic disorders, cancer, and neurodegenerative diseases. PubMed Central
A wealth of evidence now demonstrates that a decline in cellular NAD+ is a feature of ageing and may play a role in the process. PubMed Central
This age-related decline has driven significant scientific interest in compounds that can restore or boost NAD+ levels — making it one of the most active areas of longevity research globally.
NAD+ and Mitochondrial Function
One of the primary reasons NAD+ has become so important to researchers is its role in mitochondrial health. Mitochondria are the energy-producing organelles of every cell, and NAD+ is essential to their function.
NAD+ has emerged as a central metabolic cofactor and signalling molecule that regulates processes fundamental to health and longevity, including energy metabolism, mitochondrial function, inflammation, and DNA repair. Importantly, intracellular NAD+ levels decline with age across multiple tissues and organ systems, and restoring NAD+ content has been shown to reinstate cellular and physiological function in various model systems. Sciexplor
NAD+ and DNA Repair
Beyond energy metabolism, NAD+ plays a critical role in DNA repair mechanisms. NAD+ depletion is a key molecular characteristic observed in certain cellular models of premature ageing, contributing to mitochondrial dysfunction and impaired DNA repair pathways. PubMed Central
Enzymes called PARPs — poly-ADP-ribose polymerases — consume NAD+ as part of the DNA repair process. When DNA damage is extensive, PARP activation can significantly deplete cellular NAD+ stores, creating a cycle that researchers are actively investigating.
NAD+ Precursors in Research
Because direct administration of NAD+ faces bioavailability challenges, much of the current research has focused on NAD+ precursor compounds — molecules that the body converts into NAD+ through metabolic pathways.
The most common candidates in investigations of NAD+-boosting compounds include nicotinamide riboside, nicotinamide riboside co-administered with pterostilbene, and nicotinamide mononucleotide — identified as the most common candidates in investigations for improving physiological function. PubMed Central
What Does the Clinical Evidence Show?
A PRISMA-guided systematic review of peer-reviewed human and rodent intervention studies between January 2010 and October 2025 identified 113 eligible studies — 33 human intervention studies and 80 rodent studies. In rodent models, NAD+ augmentation was frequently associated with improvements in metabolic, mitochondrial, inflammatory, and functional outcomes. In humans, oral NR and NMN consistently demonstrated biochemical target engagement. ScienceDirect
A double-blind, randomised, crossover trial found that increasing NAD+ concentration in whole blood was associated with an increase in SIRT1, lower concentrations of pro-inflammatory cytokines in plasma including a reduction in interleukin 2, and a shift in the glycosylation profile of immunoglobulin G toward a younger biological age — all of which are likely to promote a healthier ageing trajectory. Nature
Emerging Research Areas
Most of the upcoming human trials involving NAD+ supplementation revolve around neurodegenerative disorders like Alzheimer's and Parkinson's disease. There is also a handful of trials testing the effects of boosting NAD+ on obesity and type 2 diabetes. Sciexplor
NAD+ research is also expanding into cardiovascular health, skeletal muscle function, reproductive biology, and liver regeneration — reflecting the molecule's fundamental role across virtually every major organ system.
NAD+ Research Grade Supply from BioSupply UK
BioSupply UK supplies NAD+ as a research grade compound at 99%+ purity, independently third party lab tested and HPLC verified. Available in 500mg vials with Certificates of Analysis available on request. Strictly for laboratory and in-vitro scientific research only.
This content is provided for educational and research purposes only and does not constitute medical or health advice. NAD+ supplied by BioSupply UK is intended solely for research applications.