NMN and NR: raising NAD+ is established, what it buys is not

Two supplements with an unusually clean first half to their story and an unusually thin second half. They do raise NAD+ in people. Whether that produces anything you would notice is a separate question with a separate, much weaker answer.

What NAD+ does, and why it declines

Established clinical use Nicotinamide adenine dinucleotide is a coenzyme in hundreds of reactions and the electron carrier at the centre of energy metabolism. It is also consumed — not merely recycled — by three families of enzymes: the sirtuins, the PARPs that repair DNA, and CD38. Because those enzymes destroy NAD+ in the course of working, demand rises with damage and inflammation, and tissue levels fall with age in most animals measured.

Nicotinamide mononucleotide and nicotinamide riboside are precursors on the salvage pathway. NR is converted to NMN inside the cell; NMN is one step from NAD+. Both are sold orally, and the practical question for years was whether either survives digestion in a useful form.

Established clinical use That question is now answered. Human trials of both compounds have measured increases in blood NAD+ concentrations, dose-dependently and reproducibly, with good tolerability at the doses studied. This is the part of the story that is solid, and it is worth separating cleanly from the rest.

What the trials did not find

Animal-only or theoretical Beyond the biomarker, the human results are modest and inconsistent. Trials have reported small changes in insulin sensitivity in specific groups, some measures of muscle function, and inflammatory markers, and other trials looking at similar endpoints have found nothing. No human trial has measured anything that could be called a longevity outcome, because that would take decades and nobody has run one.

The animal picture is stronger and is where the enthusiasm comes from — improvements in metabolic and vascular measures in aged mice, and the sirtuin story that connects NAD+ to the caloric-restriction literature. Extrapolating from mouse lifespan work to a human taking a capsule is exactly the step that has failed for a long list of compounds.

The NMN-versus-NR argument is largely commercial. Both raise NAD+; neither has been shown superior on a clinical endpoint in a head-to-head trial, because there are almost no clinical endpoints to compare on. The regulatory status of NMN in the United States has also been contested, which is a supply question rather than a safety one.

The caveat that deserves saying out loud

Animal-only or theoretical NAD+ is required by proliferating cells, and tumours proliferate. The concern that raising NAD+ systemically could support an existing malignancy is theoretical — there is no human evidence of harm — but it is not fringe, it appears in the app’s own drawbacks list, and it is a reasonable thing to raise with an oncologist rather than resolve from a supplement label. The same reasoning applies to anyone under active cancer surveillance.

Beyond that these are well tolerated in trials, with flushing largely absent (that is niacin, a different precursor) and gastrointestinal effects uncommon. There is no monitoring panel: the app records none, because nothing on a routine panel tracks this. Specialty NAD+ assays exist and are not standardised well enough to follow a trend against.

The reasonable position is that this is a low-risk supplement with a well-demonstrated biochemical effect and an undemonstrated clinical one, which is a perfectly respectable thing to be as long as it is described that way. Anyone with a cancer history should raise it with the clinician who manages that.

The dosing rows the app records

Off-label or community practice Reproduced from the app’s reference so you can see what it holds, not as a recommendation. Which row applies to a particular person, if any, is a clinical decision this page does not make — and rows describing supraphysiological or post-cycle use are filtered out before this table is built, so what you see here is a subset.

What the app monitors alongside it

The panel below is the app’s own monitoring note for NMN / NR (NAD+ Precursors), verbatim. The analytes in it that have a page here are linked; those pages cover what each one measures, which assay produced it and how to read a trend.

• Hematocrit on testosterone therapy
• HbA1c and fasting glucose

Drawbacks and risks the app records

From the app’s own entry, and unusually candid: most of these are statements about the state of the evidence rather than adverse effects, which is the accurate emphasis.

• Expensive for quality products
• Optimal dose for longevity benefits not established
• NMN vs NR debate ongoing — unclear which is superior
• Some debate whether oral NMN survives digestion without IV
• Long-term human longevity data still accumulating
• Theoretical concern: NAD+ feeds cancer cell metabolism

Questions people actually ask

Does oral NMN actually reach the bloodstream?

The endpoint that matters is whether NAD+ rises, and in human trials it does, for both NMN and NR. The mechanistic argument about which transporter carries what is unresolved and, for this purpose, secondary.

NMN or NR?

No head-to-head trial has separated them on a clinical outcome, largely because there are so few clinical outcomes to compare. Both raise NAD+. Availability and regulatory status differ, and that is a more practical basis for choosing than the biochemistry.

Is there a test to see if it is working?

Not a routine one. Specialty NAD+ assays exist but are not standardised well enough to follow a trend, and nothing on a standard panel reflects it. The app records no monitoring for this compound, which is honest.

How does it relate to NAD+ IV infusions?

Different route, different regulatory status and a much weaker evidence base — an infusion of NAD+ itself is not the same intervention as an oral precursor, and it is not an approved therapy for anything. That is a separate entry in the app.

Where the load-bearing numbers come from

Named rather than linked. Publisher URLs move, and a citation that resolves to a 404 two years from now is worse than one you can search for by name — every entry below is findable from the title and year alone.