NAD+ Research Overview: The Coenzyme on a Peptide Shelf
NAD+ is the odd one out on a research-peptide shelf. It is not a peptide. It is a coenzyme that every cell already makes, and it sits at the centre of how cells turn food into energy. Plenty of research shelves carry it anyway, because the NAD+ research literature is large and active. This overview clears up three things people often get wrong about NAD+, then covers the research areas, what the human trials actually tested, the formats a lab buys it in, and how a lot is tested.
Three things people get wrong about NAD+
1. "NAD+ is a peptide"
It is not. Nicotinamide adenine dinucleotide is a small molecule built from two nucleotides joined through their phosphate groups. One half carries nicotinamide, a form of vitamin B3. The other carries adenine. No amino acids, no peptide bonds. It is on peptide shelves because the people who study peptides often study metabolism too, not because it belongs to the same chemical family.
2. "The human trials tested NAD+"
Mostly they did not. Many human studies aimed at raising NAD+ used oral precursors, nicotinamide riboside (NR) and nicotinamide mononucleotide (NMN), rather than NAD+ itself. When you read a headline about an NAD+ trial, check which molecule was given. It is usually a precursor.
3. "More NAD+ means better function"
The data are mixed. Precursor trials do raise NAD+ metabolites in blood. Whether that changes how muscles or vessels perform is a separate question, and a 2025 meta-analysis of older adults found no significant muscle benefit. More on that below.
What NAD+ does in a cell
NAD+ has two jobs. The first is the one in every biochemistry textbook: it carries electrons in the redox reactions of energy metabolism, cycling between NAD+ and NADH as fuels are broken down. The second job is newer in the literature. NAD+ is consumed as a substrate by enzymes that are not about redox at all: sirtuins, poly(ADP-ribose) polymerases (PARPs) and CD38. Through those enzymes it is linked to DNA repair, chromatin regulation and immune cell function. Covarrubias et al., 2021 is a thorough review of both roles and of how they change with age.
NAD+ and NADH
The plus sign matters. NAD+ is the oxidised form, ready to accept electrons. NADH is the reduced form, carrying them. A cell cycles between the two constantly, and the balance between them is one readout of its redox state. When a paper reports "NAD+ levels", check whether it measured NAD+ alone, NADH alone, or the total pool, because the three numbers answer different questions. On a research shelf the material is NAD+, the oxidised form, which is also the form that is sensitive to light and to breakdown in solution.
The NAD+ research areas
- Cellular redox and energy metabolism. The classic role, studied in every tissue.
- Sirtuin, PARP and CD38 biology. How the consuming enzymes compete for the NAD+ pool.
- Age-related NAD+ decline. Tissue NAD+ levels have been reported to fall with age in rodents and humans. Why, and what it means, is an open question.
- NAD+ precursors in human trials. NR and NMN studies in people.
- Muscle and vascular function in older adults. The functional endpoints the precursor trials try to move.
What the animal and human work found
Rajman et al., 2018 reviewed the in vivo evidence for NAD-raising molecules in animals. The review contains strong claims about animal models that we will not repeat here, because animal work does not settle human questions, and our job is to say what is established.
In people, Martens et al., 2018 ran a crossover trial of nicotinamide riboside in healthy middle-aged and older adults. NAD+ in blood went up, and the precursor was well tolerated over the study period. That is a biomarker result. Prokopidis et al., 2025 then pooled randomised trials of NR and NMN in adults over 60 and found no significant effect on muscle mass, strength or gait speed. Put together: precursors reliably raise the metabolite; the functional payoff in older adults has not shown up in pooled data.
Status today
NAD+ is an endogenous metabolite and an investigational compound. It is not an FDA-approved drug for any indication. Human evidence is mostly about precursors, and the functional results are mixed. That is the honest summary, and it is a perfectly good reason to keep studying it. The open questions are specific: why tissue levels fall with age, which consuming enzyme drives the drop in which tissue, and whether raising the pool changes anything downstream. Those are bench questions, and they are the kind a lab can design around.
The formats a lab buys it in
Unlike most peptides, NAD+ sits on our shelf in three presentations. We list them as formats only. Which one a lab chooses depends on the experiment, and nothing here is guidance on use.
| Format | Presentation | Storage | House code |
|---|---|---|---|
| Vial | Lyophilised powder, 500 mg or 1000 mg, crimp-sealed glass vial with flip-top cap | -20 °C, desiccated, protect from light | PTY-NAD-500, PTY-NAD-1000 |
| Spray | 500 mg in a 10 mL spray bottle with pump and overcap | 2 to 8 °C, protect from light | PTY-NAD-SP-500 |
| Dissolving strips | 30 strips in a hinged tin | Room temperature, sealed, away from moisture | PTY-NAD-ST-30 |
Two storage notes stand out. Every format says protect from light or keep sealed, because NAD+ is sensitive to light and moisture. And the three formats have three different temperatures. A powder keeps best frozen; a solution keeps best cold; a dry strip keeps best dry at room temperature. Read the label for the format you have, not the one you expect.
How an NAD+ lot is tested
Because NAD+ is a small molecule rather than a peptide, the testing looks a little different. HPLC is still the main tool. It separates NAD+ from its breakdown products, which matters because the molecule degrades in solution and in light. Mass spectrometry confirms identity by exact mass. For the vial format, the certificate also records appearance and the fill weight. Each lot's certificate states its measured purity and identity. For the spray and the strips, documentation covers the finished format as well as the raw material that went into it.
Frequently asked questions
Does the NAD+ in a spray or strip differ from the vial?
The molecule is the same. The format, container and storage conditions differ, and so does the paperwork, because a finished spray or strip is documented as a format and not only as a raw powder.
Why do so many NAD+ papers mention sirtuins?
Because sirtuins consume NAD+ as a substrate rather than just borrowing it for an electron transfer. That links the NAD+ pool to chromatin regulation and DNA repair, which is why the sirtuin, PARP and CD38 enzymes come up in most reviews.
Has NAD+ itself been through a controlled human trial?
The human trials in our references used precursors, NR and NMN, rather than NAD+ itself. If you see a trial described as an NAD+ trial, check which molecule was actually given.
What should an NAD+ certificate show?
An HPLC chromatogram with the main peak and any breakdown products, mass spectrometry confirming identity, appearance, and the fill weight for a vial. The certificate states the measured purity and identity for that lot.
See it in the catalogue: NAD+.
For laboratory research use only. Products sold by Amino Party Peptides are not drugs, foods, supplements or cosmetics and are not for human or veterinary use. This article summarises published literature; it is not medical advice and not a usage guide.