NMN (Nicotinamide Mononucleotide).

NMN raises NAD+, the coenzyme that sirtuin enzymes must consume to carry out their regulatory activity. Resveratrol is a well studied sirtuin activator, so the pair meets on the same pathway from two ends, one supplying the substrate and the other prompting the enzyme.

As NAD+ turns over, the body disposes of the leftover nicotinamide by tagging it with a methyl group, which draws on its pool of methyl donors. Betaine (trimethylglycine) is a methyl donor, so it helps replenish the methylation capacity that NMN metabolism leans on.

NAD+ from NMN enters the mitochondrial electron transport chain as NADH and hands its electrons to the first complex, which passes them to coenzyme Q10 at the next step. Both are sequential carriers in the same chain that supports normal cellular energy production.

CD38 is one of the main enzymes that degrade NAD+, and apigenin slows CD38 activity. Alongside NMN it works from both directions, NMN adding to the NAD+ pool while apigenin restrains a route that draws it down.

NMN adenylyltransferase adds an adenylyl group to NMN to make NAD in a single step. NMN is the last intermediate before the finished cofactor.

NR is dephosphorylated NMN, and the two interconvert through nicotinamide riboside kinase and extracellular phosphatases before entering cells. They reach NAD by the same final step.

NAMPT condenses nicotinamide with PRPP to make NMN, so nicotinamide sits one enzyme upstream. That NAMPT step is the bottleneck NMN supplementation bypasses.

Nicotinic acid builds NAD through the Preiss-Handler enzymes rather than through NMN. Combining them loads the pool from two independent directions.

Nicotinamide released as NAD is consumed gets methylated using S-adenosylmethionine, and methylfolate helps regenerate that donor. Sustained NMN intake raises the methyl demand, which is why methyl support is standard in these formulas.

Pterostilbene raises sirtuin activity and each deacetylation spends one NAD, so it creates demand that the NMN supply meets. It is the methylated analogue of resveratrol used for the same reason.

CD38 on the cell surface hydrolyses NMN and NAD, and quercetin inhibits it. Slowing that enzyme leaves more of a given NMN dose intact.

Spermidine promotes autophagy through hypusination of eIF5A and inhibition of EP300, a mechanism independent of NAD supply. Formulators pair it with NMN so cellular renewal and cofactor supply are both covered.

Urolithin A drives mitophagy, the removal of worn mitochondria, while NMN supplies the cofactor those mitochondria need to run. The two act on quality and capacity separately.

NMN's own backbone is nicotinamide joined to ribose-phosphate, and PRPP derived from ribose-5-phosphate is the co-substrate NAMPT needs. Ribose availability is part of what limits salvage output.

Lipoate-dependent dehydrogenase complexes reset by handing electrons to NAD, so their throughput depends on the pool NMN feeds. The pairing links cofactor supply to the enzymes that spend it.

NAD+ is built by two routes: salvage from nicotinamide-containing precursors such as NMN, and de novo synthesis from tryptophan via the kynurenine pathway to quinolinic acid. The two converge on the same nucleotide pool. Tryptophan supply therefore sets one of the two inputs to that pool and is the reason NAD+ status is not determined by B3-family intake alone.

Converting tryptophan into the NAD+ precursor quinolinic acid requires kynureninase, a pyridoxal-5-phosphate enzyme. When B6 status falls, flux down that branch drops and the salvage route carries proportionally more of the load. This is textbook cofactor dependence, not a claim that added B6 raises NAD+.

The de novo NAD+ pathway includes an FAD-dependent monooxygenase step, and the reduced nucleotide NADH transfers its electrons to the flavin of Complex I. Riboflavin adequacy is therefore built into both the making and the using of NAD+. The relationship is structural biochemistry rather than a supplement combination with trial support.

Surplus nicotinamide is cleared by nicotinamide N-methyltransferase, which spends a methyl group from S-adenosylmethionine on every molecule it processes. Regenerating that methyl pool runs through methionine synthase, a B12-dependent enzyme. Sustained high intake of nicotinamide-family precursors therefore draws on one-carbon metabolism, which is why B12 and folate status are relevant to the pathway.

S-adenosylmethionine is made from methionine and ATP, and it is the methyl donor consumed when nicotinamide is methylated for excretion. Methionine availability therefore sits directly upstream of the disposal arm of NAD+ metabolism. Naming the link is a completeness point about the pathway, not a recommendation to add methionine.

CD38 is a major consumer of NAD+ and of NMN itself, and several dietary flavones inhibit it in enzyme assays. Slowing the consumer is a different lever from adding precursor, which is why flavones appear alongside NMN in formulas. The evidence is enzymatic and preclinical, so the row is mechanistic rather than a human outcome.

PQQ is a redox cofactor associated with mitochondrial biogenesis signalling, and NMN feeds the NAD+ pool those mitochondria run on. A published trial administered the two together and reported interoception measures, which are perceptual measures rather than clinical outcomes. The pairing has been studied as a combination, which is more than most NMN stacks can say.

Beta-oxidation of fatty acids generates NADH, and carnitine is the shuttle that gets those fatty acids into the mitochondrion. NAD+ availability sets how fast the oxidative steps can run. The two inputs act on adjacent parts of the same process and have not been tested together in people.

Converting NMN into NAD+ is an adenylyl transfer from ATP catalysed by NMNAT, and the substrate that enzyme actually binds is the magnesium-ATP complex. Nicotinamide riboside kinase, which phosphorylates the dephosphorylated form, has the same requirement. Magnesium adequacy is part of the machinery rather than an additive effect.

5-methyltetrahydrofolate donates the methyl group that methionine synthase transfers to homocysteine, restarting the SAM cycle that nicotinamide methylation draws down. Heavy use of nicotinamide-family precursors therefore intersects with folate status. The stored partner list already carries methylfolate; this row names the parent vitamin for completeness of the pathway.

Extracellular conversion of NMN to nicotinamide riboside is carried out by CD73, an ecto-5'-nucleotidase, and many of the dehydrogenases that use NAD+ downstream are zinc-containing enzymes, alcohol dehydrogenase among them. Zinc status is therefore embedded in both the handling and the use of the nucleotide. This describes cofactor dependence and not an added benefit from extra zinc.