NAD+ benefits get described as energy, and that word is doing two different jobs at once. One is literal biochemistry, where NAD+ is central to how cells extract energy from fuel and is not optional. The other is a subjective feeling, which is what people buy.
The vendor we point lifters to
NAD+ from Ascension Peptides
Independently assayed material, dispatched from the US. The vial drops by half with the code below.
Quoted per 100 mg because NAD+ is dosed in hundreds of milligrams, not the single milligrams a peptide vial holds. Buying 3, 5 or 10 takes 3%, 5% or 10% off the list price. Free shipping starts at $250.
- Two independent lab reports per batch
- Free delivery above $250
- Same-day dispatch on orders before 2pm CST
Research material, laboratory use only, not for human consumption. Affiliate links: we may earn a commission at no extra cost to you. Pricing verified August 20, 2026.
The first is not in dispute. The second is where the evidence gets thin, and where the interventions studied stop matching the interventions sold.
Nothing in either category is a muscle benefit. No trial of oral precursors or of injected NAD+, in any species, has reported an increase in muscle mass or strength.
What the molecule actually does in a cell
NAD+ is a coenzyme present in every cell, and it holds two roles that are worth separating because they behave differently.
In the first, it is an electron carrier. It cycles between an oxidised form, NAD+, and a reduced form, NADH, accepting and donating electrons through glycolysis, the citric acid cycle and oxidative phosphorylation. In this role it is not consumed. It shuttles back and forth, and the total pool is what matters.
In the second, it is a substrate that gets used up. Enzymes including sirtuins, PARPs and CD38 cleave NAD+ as part of their normal function, releasing nicotinamide. The salvage pathway then rebuilds NAD+ from that nicotinamide, which is where dietary and supplemental precursors enter the system.
The consequence is that the size of the NAD+ pool reflects a balance between consumption and resynthesis. That is a real and interesting piece of cell biology, and it is the honest basis for the whole field.
NAD+ benefits sorted by which intervention produced them
| Claimed benefit | Intervention that was actually studied | What was found | Organism |
|---|---|---|---|
| Raises NAD+ levels in the body | Oral nicotinamide riboside or nicotinamide mononucleotide | Blood NAD+ metabolites rise reliably | Human |
| Improves mitochondrial function in muscle | Oral precursors, in trials examining muscle | Effects limited or absent despite the blood rise | Human |
| Improves metabolic and mitochondrial measures | Precursors in animal models | Reported improvements | Mouse |
| Increases subjective energy | Mostly intravenous NAD+ in clinic settings | Uncontrolled reports, no placebo comparison | Human |
| Slows ageing | Nothing that measures ageing as an outcome | No such demonstration | None |
| Builds or preserves muscle | Neither form has been tested for this | No outcome reported | None |
Read the first two rows together. The marker moved and the tissue largely did not, in the same species, with the intervention that has the best evidence behind it.
The decline story, and how firm it is
The premise underneath every sales page is that NAD+ falls with age and that restoring it reverses something.
The first half has support. Declining NAD+ levels with age have been reported in rodent tissues and in human tissue measurements, and there are plausible mechanisms, including increased consumption by CD38 and by DNA repair enzymes as damage accumulates.
The second half is the leap. A measured decline in a molecule is a description of ageing, not necessarily a cause of it, and correcting a measurement is not the same as correcting the process that produced it. Plenty of things decline with age. Restoring one of them to a youthful reading does not restore the tissue it was measured in.
That distinction is not hypothetical here. It is exactly what the muscle trials ran into.
What happened when precursors met skeletal muscle
This is the most useful body of work for anyone on this site, and it is not encouraging.
Trials of oral nicotinamide riboside in older adults have reported that NAD+ related metabolites rose in blood, while measures taken in skeletal muscle showed limited or no change. The intervention did what it was designed to do at the level of the marker, and the tissue that the whole rationale points at did not follow.
There are several possible explanations. Muscle may maintain its own NAD+ supply largely through the salvage pathway and be relatively insulated from what circulates. The doses or durations may have been insufficient. The participants may not have been depleted enough to show a change.
Any of those could be true. None of them is a result, and the result that exists is a null one in the relevant tissue.
The energy claim, and why it resists testing
The most common reported benefit, particularly from infusion clinics, is a subjective lift in energy and clarity.
This is the hardest kind of claim to evaluate, and not because people are lying. Someone who has paid a substantial sum, spent hours in a clinic chair, been attended to, and been told what to expect is in close to ideal conditions for a placebo response. The reported effect is real to them and tells you almost nothing about the compound.
Untangling it requires a placebo controlled design with blinded participants. In this corner of the field, those designs are largely absent for the infused and injected forms.
The benefit that is real and is not for sale
There is a version of this subject with genuine human evidence in the relevant tissue, and it is training.
Skeletal muscle maintains its NAD+ supply largely through the salvage pathway, and exercise training has been reported in humans to increase expression of the salvage pathway enzyme NAMPT in skeletal muscle. That is a direct measurement, in human muscle, from an intervention that costs nothing.
It does not prove supplementation is pointless, since nobody has properly tested the combination. It does mean that the reader asking this question is already performing the intervention with the better evidence, and that a vial is being sold into a space training already occupies.
Why the injected form cannot inherit the oral evidence
A reader who has followed this far will notice that almost every benefit with human data attached came from a capsule, and the product being marketed comes in a vial. Those cannot be treated as the same intervention, for a specific biochemical reason.
NAD+ is a large, charged dinucleotide. Published biochemistry describes extracellular NAD+ being acted on by enzymes at the cell surface, including CD38 and ectonucleotidases, which break it down into smaller components such as nicotinamide riboside and nicotinamide. Those smaller pieces are what get taken up and rebuilt into NAD+ inside the cell.
If that is the dominant route, then injecting NAD+ is an expensive and invasive way of delivering precursors, and it would be reasonable to expect an outcome no better than the oral versions produced, which in skeletal muscle was not much.
This is a mechanistic argument rather than a settled finding, and it should be labelled as one. It has not been resolved by a trial comparing the two routes with tissue level outcomes in humans. But it is enough to block the inheritance. Anyone claiming the injected form benefits from the precursor literature is asserting an equivalence the biochemistry actively questions, and no study has established it.
What is left when the claims are sorted
A coenzyme that genuinely matters, a decline with age that is genuinely measured, an oral precursor that genuinely raises a blood marker, and a muscle level result that has repeatedly failed to appear.
For injected NAD+ specifically there is less again: no approved product in any market, no controlled trial base, and the unresolved uptake question described above.
That is a defensible summary of where the field currently stands, and it is a considerably narrower one than the summary printed on any label or clinic website.
Questions about the benefit claims
Does NAD+ increase muscle mass?
No trial of oral precursors or of injected NAD+, in any species, has reported an increase in muscle mass. There is also no described mechanism connecting it to myostatin, satellite cells or muscle protein synthesis.
Is the evidence for NAD+ or for something else?
Most of the human trial evidence concerns oral precursors, nicotinamide riboside and nicotinamide mononucleotide, rather than injected NAD+. Statements about extensive human study almost always refer to those.
Does raising blood NAD+ mean it is working?
It means the marker responded. In older adults the same trials that raised the blood marker reported limited or absent effects inside skeletal muscle, so the marker has already failed as a proxy for the outcome.
Could improved mitochondrial function help me train harder?
That is the coherent hypothesis and the reason the research is worth following. It has not been demonstrated in human muscle following supplementation, so it remains a hypothesis rather than a benefit.
Is the energy people report genuine?
The experience is genuine. Whether the compound caused it is unresolved, because the settings in which it is most often reported lack placebo controls and are unusually favourable to expectation effects.