Research Overview
The coenzyme
NAD+ is built from a nicotinamide mononucleotide half and an adenosine monophosphate half joined through a pyrophosphate bridge. Its nicotinamide ring accepts a hydride to give NADH, making the NAD+/NADH couple the principal redox carrier of central metabolism. Separately, NAD+ is cleaved as a substrate — not merely used catalytically — by sirtuins, PARPs and CD38, which is why cellular pools turn over continuously and why synthesis and salvage pathways receive so much attention in ageing research.
Why the oral format is studied
The dinucleotide is large, doubly charged at physiological pH and chemically labile: it hydrolyses in alkaline conditions and is a substrate for glycohydrolases in the gut. Published work therefore asks whether orally administered NAD+ is absorbed intact at all, or whether measured increases in tissue NAD reflect degradation to nicotinamide riboside, nicotinamide mononucleotide and nicotinamide followed by resynthesis through the salvage pathway. Studies comparing routes and precursors are a substantial part of this literature.
Common research endpoints
- Tissue and whole-blood NAD+ measurement by LC-MS/MS after different routes and precursors.
- NAD+/NADH ratio as a readout of cellular redox state in metabolic models.
- Sirtuin-dependent deacetylation and PARP activity following DNA damage.
- Mitochondrial function assays in aged or metabolically stressed cells.
- CD38 activity, a major NAD-consuming enzyme that rises with age in reported models.
