NAD+
Nicotinamide Adenine Dinucleotide
NAD+ (nicotinamide adenine dinucleotide) is a coenzyme found in every living cell, essential for mitochondrial energy production, DNA repair, sirtuin activation, and hundreds of other enzymatic reactions. NAD+ levels decline significantly with age — by up to 50% between ages 40 and 60 — and this decline is now considered a hallmark of biological aging. Researchers study NAD+ because replenishing cellular NAD+ addresses one of the most upstream and universal mechanisms of age-related decline.
Aliases: Nicotinamide Adenine Dinucleotide, NAD
- Research score
- 8/10
Key fact
Participates in 500+ enzymatic reactions; levels drop ~50% between ages 40-60
Mechanism
Nicotinamide adenine dinucleotide (NAD+) is an essential coenzyme in every living cell, participating in 500+ enzymatic reactions. It serves as an electron carrier in mitochondrial oxidative phosphorylation (energy production), a substrate for sirtuins (SIRT1-7, NAD-dependent deacetylases that regulate cellular aging, DNA repair, inflammation, and metabolism), a substrate for PARPs (poly-ADP-ribose polymerases for DNA repair), and a signaling molecule for CD38-mediated calcium signaling. NAD+ declines with age due to increased CD38 activity, decreased NAMPT expression, and increased DNA damage driving PARP consumption. Subcutaneous NAD+ injection bypasses first-pass metabolism and the absorption limitations of oral precursors (NMN, NR).
Evidence note
Emerging — NAD+ biology is extremely well-established (Nobel Prize-level science). Clinical use of IV NAD+ has decades of history (addiction medicine since the 1960s). Subcutaneous injection is newer but increasingly common via compounding pharmacies. The gap is in rigorous RCTs specifically for SC NAD+ in healthy aging populations.
Studies
NAD+ and sirtuins in aging
Declining NAD+ levels drive age-related sirtuin dysfunction, contributing to metabolic and neurodegenerative disease.
Open source · PMID 24360282NAD+ supplementation in aging
NAD+ restoration improved mitochondrial function, stem cell renewal, and lifespan in animal models.
Open source · PMID 29514064NAD+ in human clinical trials
Oral NAD+ precursors safely raised blood NAD+ levels and improved physical performance in older adults.
Open source · PMID 33037420
FAQ
Is NAD+ the same as niacin/vitamin B3?
NAD+ is the active coenzyme that niacin (B3) is used to produce. Niacin is a precursor; NAD+ is the functional molecule.
Why is it more expensive?
NAD+ requires significantly higher doses (750mg vs. 5-10mg for most peptides) and has higher synthesis and stability costs.
Why not just take NMN or NR supplements?
Oral precursors (NMN, NR) must be converted to NAD+ in the body, with variable absorption. Direct NAD+ administration bypasses conversion steps. Both approaches have research support.
For research and educational use only. This content is not medical advice.