NAD+
NAD+ (nicotinamide adenine dinucleotide) is an essential redox cofactor and substrate for sirtuins and PARP enzymes whose levels decline with age; oral precursor supplementation (NMN, NR) and direct NAD+ infusion both reliably raise blood NAD+ levels in humans and appear generally well tolerated in short-term trials, but as of 2025 the evidence that this translates into meaningful anti-aging or disease-modifying clinical benefit remains preliminary and inconsistent across studies.
This page is a research-orientation summary, not a dosing guide. For anything beyond general background, read the primary literature or talk to a qualified clinician — specifics like amount, frequency, or administration aren't something we publish here.
What it does & how it works
NAD+ is generated mainly via the salvage pathway from nicotinamide, nicotinamide riboside (NR), or nicotinamide mononucleotide (NMN) — a pathway rate-limited by the enzyme NAMPT — and to a lesser extent via de novo synthesis from tryptophan. As an obligate cofactor, NAD+ and its reduced form NADH drive cellular redox reactions and fuel NAD+-consuming enzymes including sirtuins (SIRT1-7), poly(ADP-ribose) polymerases (PARPs), and CD38, which regulate mitochondrial biogenesis, DNA repair, and metabolic gene expression. Because tissue NAD+ pools decline with age and in some chronic diseases, raising NAD+ availability — directly or via precursor supplementation — is hypothesized to restore sirtuin- and mitochondria-linked signaling capacity.
Typical results seen in research
In human trials, oral NMN and NR supplementation consistently raise blood NAD+ metabolome markers and are generally well tolerated at studied doses, with some trials reporting modest improvements in measures such as arterial stiffness, while others show no significant change in insulin sensitivity or physical performance. Direct intravenous NAD+ is used in some clinical and wellness settings, but rigorous placebo-controlled efficacy data specific to IV NAD+ (as distinct from oral precursors) remain sparse, and a 2025 review of the human ageing literature concluded that clinical evidence for meaningful healthspan benefit is still preliminary and inconsistent across trials.
How it’s commonly used
NAD+ and its precursors are used via oral supplementation (capsules or tablets of NR or NMN) or by intravenous or subcutaneous infusion of NAD+ itself, typically in clinic- or wellness-center-based settings for the infused form. Oral precursor forms are widely sold as over-the-counter dietary supplements, while IV administration is generally delivered under practitioner supervision.
- Nature Metabolism · 2025 NAD+ precursor supplementation in human ageing: clinical evidence and challenges
- Scientific Reports · 2022 Safety evaluation of β-nicotinamide mononucleotide oral administration in healthy adult men and women
- Scientific Reports · 2023 Nicotinamide adenine dinucleotide metabolism and arterial stiffness after long-term nicotinamide mononucleotide supplementation: a randomized, double-blind, placebo-controlled trial
Curated from published literature for research orientation. Not an exhaustive review, and not a substitute for reading primary sources.