Mazdutide

1 Identity

Acylated lipopeptide bearing a long-chain fatty diacid on a spacer, and carrying a non-proteinogenic residue - not a plain peptide, and not classifiable by residue count. Approved as a medicine in China in 2025; not approved in the United States. CAS 2259884-03-0 (commonly published, carried on both institutional datasheets). Class descriptors used in the literature - dual glucagon-receptor and GLP-1-receptor agonist, oxyntomodulin analog - describe pharmacology and are not identity statements. Not synonyms and each a different article: retatrutide, survodutide, tirzepatide.

Sequence

H-His-Aib-Gln-Gly-Thr-Phe-Thr-Ser-Asp-Tyr-Ser-Lys-Tyr-Leu-Asp-Glu-Lys-Lys-Ala-Lys(AEEA-AEEA-gamma-Glu-eicosanedioyl)-Glu-Phe-Val-Glu-Trp-Leu-Leu-Glu-Gly-Gly-Pro-Ser-Ser-Gly-NH2. Thirty-four residues, not thirty-nine: a glucagon(1-29) scaffold carrying 2-aminoisobutyric acid (Aib) at position 2, extended at the C-terminus by Gly-Pro-Ser-Ser-Gly, and terminating as a primary glycinamide - not a free acid. Lys20 bears a side-chain conjugate of two 8-amino-3,6-dioxaoctanoic acid (AEEA) spacers, one L-gamma-glutamyl unit and a C20 fatty diacid (eicosanedioic acid) attached through one carboxyl, leaving a free carboxylic acid at the distal end. No cysteine, no disulfide. Four lysines are present in the chain, which is why acylation position is a release attribute rather than an assumption.

Molecular formula

C210H322N46O67. Des-acyl backbone amide C173H257N43O55. The C19-monoacid article that one institutional datasheet's written structure actually describes: C209H322N46O65.

Average mass

4,563.14 Da (C210H322N46O67); the formula on IUPAC 2021 abridged conventional atomic weights gives 4,563.141. One institutional datasheet prints 4563.1 and the other prints 4563.06; the formula value reconciles with the first exactly and with the second to within an atomic-weight revision. Des-acyl backbone amide 3,819.21, i.e. 743.94 Da lighter. C19-monoacid article 4,519.13, i.e. 44.01 Da lighter - exactly one CO2.

Monoisotopic mass

4,560.32034 Da neutral (C210H322N46O67). [M+3H]3+ 1,521.11406; [M+4H]4+ 1,141.08736; [M+5H]5+ 913.07124. Release measurement on a 4.6 kDa conjugate is the deconvoluted average mass from a multiply-charged envelope with the charge states printed, not a monoisotopic peak. Des-acyl backbone amide 3,816.86352. C19-monoacid article 4,516.33051. All values follow from the stated formulas.

Salt / variant note

Two articles plus a published-descriptor error worth recording in full, because it is the same failure mode this catalog documents elsewhere: a name in wide circulation, no settled structure in the sales channel, and a price band wide enough to hide a cheaper molecule inside it. The error: the datasheet that prints 4563.06 writes the acyl group as 'Nonadecanoic acid', a C19 mono-acid. Atom-counting that written structure returns C209H322N46O65 = 4,519.13 average / 4,516.33051 monoisotopic - 44.01 Da, exactly one CO2, short of the formula and the mass printed on that same datasheet. Substituting the C20 fatty diacid (eicosanedioic acid) reproduces the published C210H322N46O67 = 4,563.14 exactly. So the published formula is right and the written acyl name on the datasheet is wrong. Separately, the other datasheet's own description of a '39-amino acid backbone' does not match the 34-residue chain that reproduces the formula either. Two institutional suppliers, one correct formula, two incorrect prose structures. (1) Mazdutide as specified, C210H322N46O67, 4,563.14 / 4,560.32034. (2) The C19-monoacid mis-acylated article that the datasheet prose actually describes, C209H322N46O65, 4,519.13 / 4,516.33051 - a manufacturer building to the written datasheet rather than to the formula would produce exactly this, and it would be a different molecule sold under the name. (3) Des-acyl backbone amide C173H257N43O55, 3,819.21 / 3,816.86352 - 743.94 Da lighter, the product of a failed acylation. (4) Program-adjacent substitution candidates that would arrive under a dual- or triple-agonist label - retatrutide, survodutide, tirzepatide, cotadutide - are named here without masses, because no formula for them was checked against a primary source, and no mass is printed here that is not tied to a formula that was checked. (5) acylation positional isomers: four lysines are present in the chain, and an acyl on the wrong one is exactly isobaric with the correct molecule and invisible to intact mass at any resolution. (6) D-epimers at residues neighboring Aib2 are likewise exactly isobaric. (7) C-terminal free acid instead of the glycinamide, +0.98 Da.

2 Class & testing panel

Form

Single article

Testing panel

P2 — panel definition

3 Primary sources & evidence

The index reports the design and provenance of the literature, not a conclusion about effect.

Published literature exists and is a recent, substantial sponsor-run clinical program. What exists, by study type: Phase 2 and multiple Phase 3 studies conducted by Innovent Biologics in China, with peer-reviewed publication of the pivotal results, and Chinese NMPA approval in 2025. There is no United States approval and no FDA review record. Registry identifiers for the Chinese trials are taken from the sponsor's registrations and are re-verified rather than carried forward on trust. The citation index carries the published Phase 3 reports and the approval record together. No statement is made anywhere in this record about what the molecule does; the entries above are statements about which documents exist.

4 Storage & specification

Storage

Lyophilized solid held at -20 degrees C plus or minus 5 degrees C, desiccated and protected from light, in low-adsorption glass, because acylated peptides bearing a C20 diacid are surface-active and adsorb to borosilicate - a property that biases low-concentration recovery and is therefore an analytical attribute rather than a handling nicety.

Shelf life

Each lot is dated from its date of manufacture and carries a retest interval set on that lot's own stability data rather than a catalog-wide figure. The attributes that limit it are the acyl group and the C-terminal amide: loss of the C20 fatty diacid gives the des-acyl backbone amide 743.94 Da lighter, and hydrolysis of the glycinamide gives the free acid at +0.98 Da. Both are followed by accurate mass on the deconvoluted average.