NAD+ (Nadide): CAS 53-84-9, Structure Beside NADH and NADP+, and Free Acid vs Sodium Salt

The CAS number of NAD+ (nicotinamide adenine dinucleotide, INN nadide) is 53-84-9, the registry number for the free acid, recorded in PubChem as CID 5892 and in the FDA GSRS as UNII 0U46U6E8UK, with formula C21H27N7O14P2 and an average molecular weight of 663.43 g/mol. NAD+ is a dinucleotide, not a peptide: it contains no amino-acid residues. This page sets its structure beside NADH, NADP+ and NADPH, states which form and salt the Pepta Labs listing quotes, and explains why the sodium salt carries a different CAS number and mass.

How do NAD+, NADH, NADP+ and NADPH differ in structure?

NAD+, NADH, NADP+ and NADPH share one skeleton: an adenosine nucleotide and a nicotinamide nucleotide joined through a pyrophosphate (P-O-P) bridge, with both ribose units in the beta-D configuration. They differ at only two sites. The first is the nicotinamide ring, which is an aromatic pyridinium cation in the oxidized forms (NAD+, NADP+) and a neutral 1,4-dihydropyridine in the reduced forms (NADH, NADPH). The second is the 2'-hydroxyl of the adenosine ribose, which is free in NAD+ and NADH and carries an extra phosphate group in NADP+ and NADPH.

Formulas, average molecular weights and CAS numbers are as recorded in PubChem (PubChem gives NAD+ as 663.4 g/mol; 663.43 is the listing value to two decimals), and UNII codes as recorded in the FDA GSRS, checked on 2026-09-24. The NAD+ row matches the Pepta Labs identity record for the listing. Monoisotopic masses are calculated from each formula. Only NAD+ is listed at Pepta Labs; the other three rows are registry records for comparison and are not sold here.

NAD+ vs NADH: what changes in formula, mass and UV absorbance?

NAD+ is not the same compound as NADH: NAD+ is C21H27N7O14P2, 663.43 g/mol, CAS 53-84-9, and NADH is C21H29N7O14P2, 665.4 g/mol. NADH is NAD+ with two more hydrogens: the nicotinamide ring gains a hydride at its 4-position, which removes the pyridinium positive charge and changes the formula from C21H27N7O14P2 to C21H29N7O14P2. The calculated monoisotopic masses differ by 2.016 Da (663.109 against 665.125), so a mass spectrum separates the two directly. The two forms also differ in UV absorbance: both absorb near 260 nm from the adenine ring, but only the reduced dihydropyridine ring absorbs near 340 nm, so a 340 nm band indicates NADH or NADPH and its absence is consistent with NAD+.

NAD+ vs NADP+: what does the extra phosphate change?

NADP+ carries one extra phosphate group on the 2'-oxygen of the adenosine ribose, which adds HPO3 to the formula (C21H28N7O17P3) and 79.966 Da to the monoisotopic mass. The nicotinamide end is the same pyridinium ring in both, so the two oxidized forms share the 260 nm absorbance and are told apart by mass and by their registry numbers, 53-84-9 for NAD+ and 53-59-8 for NADP+.

Which form and salt does the Pepta Labs vial contain?

The Pepta Labs NAD+ listings state the oxidized free acid: CAS 53-84-9, formula C21H27N7O14P2 and molecular weight 663.43 Da, as shown on the NAD+ 500 mg and NAD+ 1000 mg product pages. The identity record gives the salt form as the free acid, a pyridinium inner salt (zwitterion): one phosphate proton is lost to balance the positive charge on the ring nitrogen, so the solid is electrically neutral without any added counter-ion. As a free acid NAD+ is a hygroscopic white to off-white powder. Both listings state the same compound, supplied as lyophilized powder in a sealed glass vial at a supplier-stated nominal quantity of 500 mg or 1000 mg.

How do the free acid and the sodium and lithium salts differ?

Chemical catalogs also carry NAD+ as a sodium salt and a lithium salt, each under its own CAS number and each a different solid from the free acid. In the salt forms the remaining phosphate proton is replaced by a metal ion, so the formula weight rises while the NAD+ content per gram falls.

Gram for gram, the sodium salt contains about 3.2% fewer moles of NAD+ than the free acid (663.43 divided by 685.4), and hydrated grades of either form weigh more again. A document quoting 685.4 g/mol therefore describes a different solid from one quoting 663.43 g/mol. The formula weight stated on the Pepta Labs listing is the free-acid figure, 663.43 g/mol; the monoisotopic 663.109 Da is the figure a mass spectrum reads.

Which ions should a mass spectrum of NAD+ show?

Electrospray mass spectrometry reads the monoisotopic mass, so an NAD+ spectrum shows the protonated or deprotonated molecule, never a peak at the average weight of 663.43. The table gives calculated values from C21H27N7O14P2.

A sodium adduct forms from the free acid as readily as from a sodium salt, so the salt form is read from the form a document states, not from adduct peaks. HPLC area percent cannot show the counter-ion either, since the free acid and the sodium salt give the same chromatogram. The same calculated-ion convention is applied across the catalog in the expected mass table.

Where are the NAD+ analytical report, storage conditions and US status covered?

Each NAD+ size with a live listing:

Prices are read from the catalog when this page loads; price per mg divides the single-unit price by the supplier-stated quantity. Multi-unit pack prices are shown on each product page.

• Analytical report: Independent third-party HPLC purity analysis and mass-spectrometry identity confirmation, commissioned through the purchasing group on a sampled production run from the source. Pepta Labs does not test in-house. The listings showed 99.5% reported HPLC purity for the sampled production run as of 2026-09-24; vial labels do not carry lot or batch numbers. The report is sent by email on request through the report request form, and each field is explained in the COA verification guide.
• Storage: the identity record gives 2-8 C short term and -20 C long term, protected from light and moisture; sealed-vial handling for hygroscopic powders is in the peptide storage guide.
• US status: in the FDA 503A bulk substances nominations list (updated May 14, 2026), nicotinamide adenine dinucleotide (NAD) is in Category 1, the substances under evaluation, and the beta-NAD disodium salt trihydrate is listed separately in Category 3, the nominations the agency regards as inadequately documented; NAD+ does not appear in Category 2. Those lists concern compounding pharmacies, not the sale of a research reagent. The categories are explained in FDA Category 2 Peptides 2026 and the research-reagent framework in Peptide Legal Status 2026.
• Price per milligram: NAD+ is listed as NAD+ 500 mg from $56.41 and NAD+ 1000 mg from $98.21, and the price per milligram of both sizes is in the table above and, next to every other non-incretin listing, in the research compound price-per-mg table.

Registry numbers and molecular weights for every other listed compound are collected in the CAS number and molecular weight table.

Frequently asked questions

Is NAD+ a peptide?

No. NAD+ is a dinucleotide with no amino-acid residues and no peptide bonds: it is built from adenine, nicotinamide, two ribose sugars and two phosphate groups, formula C21H27N7O14P2, 663.43 g/mol. Sequence and net peptide content do not apply to it. Pepta Labs lists it beside peptides as a non-peptide research compound; the difference is set out in What Are Research Peptides.

Is NAD+ the same as NADH?

No. NAD+ is the oxidized form, C21H27N7O14P2, 663.43 g/mol, CAS 53-84-9, PubChem CID 5892, and NADH is the two-electron reduced form of the same dinucleotide, C21H29N7O14P2, 665.4 g/mol, a separate registry entry; only NAD+ is listed at Pepta Labs.

What is the difference between NAD+ and NADH?

NADH is the reduced form of the same dinucleotide: the nicotinamide ring gains a hydride, giving C21H29N7O14P2 (665.4 g/mol, CAS 58-68-4) and removing the pyridinium positive charge. The calculated monoisotopic masses differ by 2.016 Da, and only NADH absorbs near 340 nm.

Is nadide the same as NAD+?

Yes. Nadide is the INN and USAN name for NAD+ in its oxidized free-acid form. PubChem CID 5892 is titled Nadide and carries CAS 53-84-9, and the FDA GSRS records it under UNII 0U46U6E8UK; beta-NAD and diphosphopyridine nucleotide (DPN) are older names for the same structure.

What is the CAS number of NAD+?

CAS 53-84-9, the registry number for nicotinamide adenine dinucleotide as the free acid (inner salt), formula C21H27N7O14P2. The sodium salt (CAS 20111-18-6) and the lithium salt (CAS 64417-72-7) carry their own numbers, and NADH (58-68-4) and NADP+ (53-59-8) are separate registry entries.

Does the NAD+ vial contain the free acid or a sodium salt?

The Pepta Labs listing states the free acid: CAS 53-84-9, C21H27N7O14P2, 663.43 Da, supplied as the pyridinium inner salt. A sodium salt would carry CAS 20111-18-6 and a formula weight of 685.4 g/mol.

Which molecular weight does the NAD+ listing state?

663.43 Da, the average molecular weight of the free acid C21H27N7O14P2, on both the 500 mg and 1000 mg listings. The calculated monoisotopic mass is 663.109 Da, and the calculated [M+H]+ ion is m/z 664.116.

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