NAD+
Nicotinamide adenine dinucleotide, a ubiquitous coenzyme, not a peptide; precursor research targets age-related NAD decline.
Overview
NAD+ (nicotinamide adenine dinucleotide) is a fundamental coenzyme found in every cell, where it shuttles electrons in redox reactions and serves as a substrate for sirtuins, PARP enzymes, and other signaling proteins. It is a dinucleotide small molecule, not a peptide, but it appears in peptide catalogs because of intense research interest in the decline of NAD+ levels with age and in precursors such as nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN).
Mechanism
NAD+ is required for ATP production through glycolysis and oxidative phosphorylation and is consumed by enzymes that regulate DNA repair, inflammation, and gene expression. The aging hypothesis holds that falling NAD+ availability impairs sirtuin activity and mitochondrial function; precursor supplementation is proposed to restore intracellular NAD+ pools.
Dosing
Human trials of the precursors NR and NMN have used a wide range of oral doses, generally from hundreds of milligrams to about one gram daily, with the specific regimens reported in each study. NAD+ itself is poorly absorbed orally and is mostly studied by intravenous infusion in early human protocols.
Expected Effects
- reliable increases in blood NAD+ levels after precursor supplementation in human trials
- improvements in some metabolic and mitochondrial markers in rodent studies
- clinically meaningful anti-aging outcomes in humans remain unproven
Side Effects & Tolerability
Short-term trials of NR and NMN report good tolerability with mild gastrointestinal symptoms at higher doses. Long-term safety, especially regarding NAD-consuming pathways such as PARP and potential effects on tumor biology, is not yet established.
Storage
NAD+ and its precursors are moisture- and light-sensitive; research-grade material should be stored per the supplier label, typically frozen or refrigerated, desiccated, and protected from light.