A NAD+ certificate of analysis is readable in six blocks: identity and the method behind it, purity with its detection wavelength, net content and the basis it is stated on, the lot number matched to the vial, the date of analysis, and the issuing laboratory. Verify it with that laboratory, not the seller.
- A certificate of analysis records measurements on one lot on one date, and applies to your vial only if the lot numbers match.
- NAD+ purity is almost always chromatographic area percent, which is blind to water, counterions and non-absorbing residues.
- The free acid is roughly 663.4 g/mol and the disodium salt roughly 707.4, so salt form must be stated before molar arithmetic can be closed.
- Absorbance near 340 nm indicates the reduced form NADH and should be flat in material sold as NAD+.
- Verification means contacting the issuing laboratory with the report number, using details found independently of the seller.
- Free nicotinamide is the impurity that flags hydrolysis in a lot stored warm or damp.
What the document claims, and what it does not
A certificate of analysis is a record of measurements made on one lot of material on one date by one laboratory. That is the whole of it. It is not a guarantee of what is in the vial on your bench, because the vial on your bench may or may not have come from the lot the certificate describes, and nothing on the paper can close that gap for you.
NAD+ certificates read differently from the peptide certificates that fill most of this section. β-nicotinamide adenine dinucleotide is a dinucleotide coenzyme, not a peptide, so there is no amino acid analysis, no peptide content by nitrogen determination, no sequence confirmation by MS/MS fragmentation of a backbone. What replaces those is a strong UV chromophore, a well-behaved reversed-phase or ion-pairing separation, an enzymatic activity assay if the supplier bothers with one, and a set of impurities that are hydrolysis products rather than deletion sequences.
The practical consequence: a certificate that has clearly been produced by pasting a peptide template over a nucleotide is telling you something about the supplier before you read a single number. Look for an identity method that suits the molecule.
- Lot number — does it match the vial, not the bag
- Identity — instrument named, salt form stated, oxidation state clear
- Purity — method, wavelength, largest impurity identified
- Net content — as-is or anhydrous, water measured
- Dates — manufacture and analysis, both present
- Issuing laboratory — findable independently, report number quotable
The identity block
Identity is where most weak certificates fail, and they fail quietly, by naming the compound in a way that does not pin down what was actually weighed.
NAD+ in its free-acid form has the molecular formula C21H27N7O14P2 and a molecular weight near 663.4, with CAS 53-84-9 assigned to the oxidized β form. PubChem carries the formula, mass and synonym set for that entry. Salt forms are separate substances with their own registry numbers, and the disodium salt is the one most commonly supplied. A certificate that says only NAD or NAD+ (98%) has not told you whether you are holding free acid, monosodium or disodium material, which matters the moment anyone converts mass to moles.
Also watch the oxidation state. NADH is a different compound with a different CAS number and a diagnostic absorbance near 340 nm that NAD+ lacks. A UV scan showing meaningful absorbance at 340 nm in a sample sold as NAD+ is either contamination with the reduced form or a labelling error, and it takes about two minutes on a spectrophotometer to check.
| Method | Establishes | Limitation |
|---|---|---|
| LC-MS, positive or negative mode | Molecular mass consistent with C21H27N7O14P2 | Does not distinguish salt form or isomeric impurities |
| RP-HPLC retention time against a reference standard | Co-elution with authentic material | Worthless without the standard identified on the certificate |
| UV spectrum, maximum near 259 to 260 nm | Adenine chromophore present; reduced form absent if 340 nm is flat | Nicotinamide and ADP-ribose also absorb near 260 nm |
| Enzymatic assay, typically alcohol dehydrogenase coupled | Cofactor activity, which no spectrum can show | Reports activity units, not chemical purity |
| 1H or 31P NMR | Structure and, with care, phosphate environment | Rare on commercial reagent certificates |
A certificate carrying mass confirmation plus a chromatographic identity check against a named standard is doing the job. One carrying neither, and simply asserting Conforms, is a statement of intent.
The purity block, and the basis it is stated on
Almost every purity figure you will see for NAD+ is chromatographic area percent: the peak of interest divided by the sum of all integrated peaks, expressed as a percentage. It is a useful number and it is not mass purity. Area percent is blind to water, blind to counterions, blind to inorganic salts, and blind to anything that does not absorb at the detection wavelength. USP General Chapter <621> sets out the chromatography and system suitability expectations that make such a number defensible in the first place.
So read the purity line together with its footnotes. A defensible one names the method, the column chemistry, the mobile phase or at least the ion-pairing approach, the detection wavelength, and the integration threshold. Detection at 260 nm will see nicotinamide, adenine, ADP-ribose and ADP, the usual hydrolysis and phosphatase products. It will not see a sodium phosphate residue at all.
Related substances deserve their own line. NAD+ hydrolyses at the nicotinamide-ribose bond, and free nicotinamide is the marker to look for in a lot that has been stored warm or damp. A certificate that reports a single largest impurity plus a total is more informative than one reporting only 99.1% by HPLC, because the identity of the largest impurity tells you which degradation route the lot has been down.
Where a supplier claims mass purity rather than area percent, the arithmetic has to close. Chromatographic purity, water content by Karl Fischer or loss on drying, residual solvents against ICH Q3C limits, and inorganic residue should sum to something near one hundred percent. If they do not, one of the numbers is decorative.
Net content, water and counterion
This is the block that quietly changes every concentration in your notebook. A vial labelled 100 mg may contain 100 mg of disodium salt as weighed, including whatever water the hygroscopic solid has taken up, or 100 mg of NAD+ calculated on the anhydrous free-acid basis. Those are different amounts of the molecule you care about.
The conversion is straightforward once the certificate states the salt form. The free acid sits at 663.4 g/mol; replacing two acidic protons with sodium gives roughly 707.4 g/mol for the disodium salt.
100 mg disodium salt × (663.4 ÷ 707.4) = 93.8 mg free-acid equivalent
100 mg ÷ 707.4 g/mol = 0.1414 mmol = 141.4 µmol
Now add water. A certificate reporting 5.0% water by Karl Fischer on an as-is basis leaves about 95 mg of actual salt in that vial, or 0.134 mmol. Brought into 2 mL of diluent the nominal figure is 50 mg/mL, while the honest molar figure is closer to 67 mM than to the 70.7 mM the label arithmetic suggests.
| Basis stated on the certificate | Content of a vial labelled 100 mg | Molar amount |
|---|---|---|
| Disodium salt, as-is, no water correction | 100 mg salt | 141.4 µmol |
| Disodium salt, anhydrous, 5.0% water measured | 95 mg salt | 134.3 µmol |
| Free acid equivalent, anhydrous | 89.1 mg NAD+ | 134.3 µmol |
A five percent discrepancy will not matter in a solubility screen. It will matter in an enzyme kinetics run where the cofactor concentration is the independent variable. The vial concentration calculator handles the mg per mL step; the basis correction is yours to apply, and it belongs in the preparation record alongside the certificate reference. The cost per mg tool is worth running on the corrected figure too, since a salt-form quote and a free-acid quote are not comparable prices.
Lot number, dates and the issuing laboratory
Three administrative fields carry more weight than the analytical ones, because they determine whether the analytical fields apply to your material at all.
| Field | Question it answers | Failure mode |
|---|---|---|
| Lot or batch number | Does this document describe the vial in my hand? | Lot absent from the vial label, or printed only on the shipping bag |
| Manufacture date | How old is the material, independent of when it was tested? | Omitted entirely, leaving age unknowable |
| Date of analysis | When were these measurements actually taken? | Conflated with the date the PDF was generated |
| Retest or re-evaluation date | When does the supplier expect the figures to need repeating? | Stated as an expiry with no stability study behind it |
| Issuing laboratory and report number | Who is accountable, and can I ask them? | A logo with no address, no report number, no analyst |
| Signature or authorised release | Did a named person take responsibility? | An image of a signature reused across every certificate |
The date pair matters more than people expect. A lot manufactured in March and tested in November has an eight-month handling history that the November purity figure absorbs silently. A lot manufactured in March and tested in March, then sold in the following January, has an unmeasured ten months. Neither is disqualifying. Both are things you want in the record, because when a result drifts, material age is the first variable to check.
Retest dates on reagent-grade material are usually conventions rather than measurements. A supplier who has run a real stability programme on the lot can say so; most cannot, and the honest reading of a bare retest date is that it reflects the supplier default. Our own position on what documentation should accompany a lot is set out in the quality standard.
Verifying the document at the laboratory
A certificate is a PDF, and a PDF is trivially editable. Verification means going around the seller.
- Read the issuing laboratory name and report number off the certificate. Ignore any contact details printed on the document.
- Find that laboratory independently, through its own site or an accreditation register. ISO/IEC 17025 accreditation bodies publish searchable scopes; a laboratory accredited for microbiological work is not thereby accredited for chromatographic assay of a nucleotide.
- Contact the laboratory with the report number and the lot number and ask them to confirm that the report exists, that it was issued to the named client, and that the results match what you are holding. Many contract laboratories will confirm existence to a third party even where they will not release content.
- Ask the supplier for the raw chromatogram as issued, not a cropped image. What you want is the integration table with retention times and areas, the injection timestamp, the column and method identifier, and the system suitability injections.
- Where the material matters, re-test. An independent identity and purity check on your own receipt is the only document that describes the vial you actually opened.
Step four separates careful suppliers from the rest quickly. A genuine chromatogram has baseline noise, labelled axes, a solvent front and an integration table that reconciles with the reported percentage. Compare two lots: if the noise pattern is identical, you are looking at one chromatogram wearing two lot numbers.
One aside on receipt inspection. NAD+ is hygroscopic, and a lot that has taken up water in transit will not match its own water-content figure any more, whatever the certificate says. Diluent choice belongs to the protocol rather than to the certificate, though the notes on bacteriostatic water cover why the diluent lot deserves its own line in the preparation record.
Red flags
- Purity stated without a method, or with a method but no detection wavelength.
- Identity given as
Conformswith no instrument named. - No salt form anywhere on the document, so molar arithmetic cannot be closed.
- Water content absent on a hygroscopic solid, alongside a mass purity claim.
- A purity figure of 99.9% or higher on a reagent lot with no supporting chromatogram.
- Lot number on the certificate that appears nowhere on the vial.
- Date of analysis later than the date you received the material, or earlier than the manufacture date.
- An issuing laboratory that cannot be found to exist independently of the seller.
- Identical chromatogram traces, retention times to three decimals, across supposedly separate lots.
- Language on the certificate describing suitability for human use, which no reagent certificate has any basis to assert.
None of these individually proves the material is wrong. Two or three together mean the document is not evidence, and material without evidence is material of unknown identity, which is a different line item in a protocol.
Regulatory position
NAD+ is an endogenous coenzyme and a long-established laboratory reagent. It is not an FDA-approved drug substance in the United States, and material supplied against a reagent certificate of analysis carries no sterility, endotoxin or lot-release assurances of the kind that a licensed medicine does, unless those tests appear on the certificate by name.
NAD+ has been the subject of FDA review under the section 503A bulk drug substances process for pharmacy compounding, and the agency maintains and periodically revises the lists arising from that process. Anyone whose work depends on the current classification should read the agency's current list directly rather than any secondary summary, including this one. Related compounds in the same metabolic family, notably nicotinamide mononucleotide, have their own distinct and separately determined regulatory status.
Status verified 26 August 2026.
FOR LABORATORY AND IN-VITRO RESEARCH USE ONLY. NOT FOR HUMAN OR ANIMAL CONSUMPTION. NOT FOR PERSONAL, MEDICAL, DIAGNOSTIC, THERAPEUTIC, OR RECREATIONAL USE.
What is NAD+ studied for?
Published research on NAD+ investigates the areas below, which is a different question from what NAD+ will do for anyone, a claim about a living system that nothing on this site is sold for.
What it is. Nicotinamide adenine dinucleotide, a helper molecule rather than a peptide.
What the research looks at. A very large basic-science record on how cells make energy, on oxidation and reduction, and on enzymes. Most of it is about what the molecule does inside cells rather than about any product sold in a vial.
How it is thought to work. It carries hydrogen back and forth in the reactions that make energy, switching between two forms, and it is also used up as raw material by two families of enzymes, the sirtuins and the PARPs. Its basic biochemistry is textbook material and nobody disputes it.
What is not established. Well-understood biochemistry says nothing about any particular preparation in a vial. NAD+ is chemically different from the precursors it is often lumped in with, and material of this kind pulls in water from the air and degrades in light, which makes the handling paperwork matter more than usual.
The full record, including the certificate for the lot in stock, is on the NAD+ product page.
Common questions
Is HPLC area percent the same as purity by weight?
How can I tell NAD+ from NADH on a certificate?
Why does the salt form change my calculations?
The certificate has no manufacture date. Does that matter?
Should I re-test material that arrives with a certificate?
How do I check that the issuing laboratory is real?
More documentation guides
Sources
- PubChem compound record for beta-nicotinamide adenine dinucleotide. Establishes the molecular formula C21H27N7O14P2, molecular weight near 663.4, and the CAS registry number 53-84-9 for the oxidized free acid; supports the salt-form and molar-mass arithmetic.
- United States Pharmacopeia, General Chapter <621> Chromatography. Defines system suitability, integration and reporting expectations that make a chromatographic area-percent purity figure defensible.
- ICH Q3C guideline on residual solvents. Establishes solvent classes and concentration limits referenced when a certificate reports residual solvent data as part of a mass-balance purity claim.
- ISO/IEC 17025:2017, general requirements for the competence of testing and calibration laboratories. Basis for checking that an issuing laboratory is accredited and that the accreditation scope covers the test being reported.
