AX-2026-042976 · Retatrutide · KP lot KP-2511-K4263

Section 1

Results

Measured against the index acceptance specification for the incretin analogues and co-agonists class. A specification is a decision the index made; a result is a measurement. See where each threshold came from.

Parameter	Method	Result	Unit	Index spec
Purity	RP-HPLC, 25 min gradient, 214 nm	97.25	% area	≥ 96.5	PASS
Total impurities	RP-HPLC, sum of reported peaks	2.75	% area	≤ 3.5	PASS
Largest single impurity	RP-HPLC — incomplete Fmoc removal (+222 Da)	1.82	% area	≤ 1.00	FAIL
Identity — theoretical monoisotopic mass	calculated from molecular formula	4728.4871	Da	—	NOT TESTED
Identity — observed monoisotopic mass	LC-MS, unit resolution (single quadrupole)	4728.5230	Da	—	NOT TESTED
Mass accuracy	observed vs theoretical	+7.6	ppm	± 15	PASS
Total peptide content	by difference from the gravimetric mass balance	86.26	%w/w	—	NOT TESTED
Target-compound content	total peptide content × purity	83.89	%w/w	—	NOT TESTED
Gross fill (as weighed)	five-place balance, under nitrogen	11.79	mg	10 mg declared	NOT TESTED
Recovered target peptide	gross fill × target content	9.891	mg	10 mg claim	NOT TESTED
Recovery against label claim	recovered ÷ claim	98.9	%	90.0 – 110.0	PASS
Water content	Karl Fischer, coulometric, duplicate	3.51	%	≤ 8.0	PASS
Counter-ion (TFA)	anion-exchange ion chromatography	9.78	%	≤ 12.0	PASS
Residual solvent + inorganic residue	estimated — see /methods/residual-solvents-q3c/	0.45	%	—	NOT TESTED
Endotoxin	not ordered on this submission	not determined	—	≤ 5.0	NOT TESTED
Sterility	not ordered on this submission	not determined	—	no growth	NOT TESTED
Appearance	visual, diffuse light, black and white background	Off-white lyophilised cake, intact	—	white to off-white intact cake	PASS
Reconstitution clarity	reconstituted per submitter procedure	Clear, colourless, no visible particulates	—	clear, no visible particulates	PASS
pH (reconstituted, 1 mg/mL)	potentiometric, two-point calibration	4.38	—	2.5 – 8.0	PASS
Retention time (observed)	RP-HPLC, 25 min gradient	17.66	min	17.53 ± 0.50 (normalised)	PASS
Peak asymmetry (10 % height)	Ph. Eur. 2.2.46	1.17	—	0.80 – 1.50	PASS
Plate count, main peak	N = 5.54 (t/w½)²	36,436	—	≥ 20,000	PASS
Resolution to nearest impurity	vs [D-Aib2]-diastereomer	0.48	—	no index criterion	REPORTED

Section 2

Chromatogram and peak integration

The figure is drawn from the table. It is not an independent illustration — if a number in the table changed, the trace would change with it.

Figure 1. RP-HPLC trace, 25 min gradient, 214 nm. Drawn from the peak-integration table below: peak positions are the reported retention times, peak areas are the reported area percentages, peak widths follow the reported plate count of 36,436, and skew follows the reported asymmetry factor of 1.17. Baseline noise is seeded from the report ID and is illustrative. The lower panel is the same trace at a stated vertical expansion with the slow gradient drift subtracted, because at full scale a 1.82 % impurity against a 97.25 % main peak is a line two pixels tall; the main peak runs off-scale there by design.

#	Peak	RT	Area (µV·s)	% area	Δ mass (Da)
1	Retatrutide — main peak	17.66	4,726,651	97.25	—
2	incomplete Fmoc removal (+222 Da)	19.67	88,458	1.82	+222.068
3	aspartimide (−18 Da)	18.25	18,955	0.39	-18.011
4	truncated (5-39)	16.06	17,983	0.37	-428.201
5	[D-Aib2]-diastereomer	17.48	5,346	0.11	0.000
6	des-Aib20 analogue	17.29	1,458	0.03	-85.053
7	retatrutide dimer	21.09	1,458	0.03	+4728.487
Closure check — purity + Σ impurities				100.00	CLOSES

Reporting threshold 0.05 % area. Peaks below it are not reported and are therefore excluded from the total, which overstates purity by their sum — see peak integration.

Section 3

Mass spectrum and identity

Theoretical monoisotopic mass 4728.4871 Da, computed from C221H342N46O68. All ppm figures on this site are against monoisotopic values — see why that matters.

Figure 2. ESI charge-state envelope, unit-resolution instrument. Sticks are placed at m/z = (M + z × 1.007276)/z for the observed neutral mass of 4728.5230 Da. Sodium (+21.982/z) and potassium (+37.956/z) adducts are shown where the parent charge state exceeds 25 % relative abundance; they are adducts of the same molecule and are not impurities.

Charge	Theoretical m/z	Observed m/z	Δ m/z	Rel. abundance (%)
7+	676.5054	676.5106	0.0052	8.5
6+	789.0885	789.0944	0.0059	55.0
5+	946.7047	946.7119	0.0072	100.0
4+	1183.1291	1183.1380	0.0089	61.7
3+	1577.1696	1577.1816	0.0120	9.4

Section 4

Gravimetric mass balance

Water, counter-ion, residual and total peptide content are exhaustive and mutually exclusive categories. They must account for 100 % of the cake mass. The index closes this to within 0.02 pp and the build asserts it.

Component	Determination	%w/w of cake
Water	Karl Fischer	3.51
Counter-ion (TFA)	ion chromatography	9.78
Residual solvent + inorganic residue	estimated	0.45
Total peptide content	by difference	86.26
Total		100.00 CLOSES

Supplier certificate, as declared

The supplier's own figures for this lot, beside the independent measurement. Divergence is assessed against the batch median, not against this single report — see rule AX-R05.

Figure	Supplier COA	This report	Index note
Purity (% area)	97.46	97.25	divergence +0.34 pp vs batch median
Total impurities (% area)	not stated	2.75
Largest single impurity (% area)	not stated	1.82
Water (%)	not stated	3.51
Counter-ion (%)	not stated	9.78
Peptide content (%w/w)	not stated	86.26
Endotoxin (EU/mg)	0.35	not determined
Method stated on certificate	NO	—	no method section — the result cannot be reconciled against any other

Section 5

Provenance and caveats

Where a sample came from changes the weight of the evidence. The index treats it as a first-class field.

Sample provenance: Supplier-supplied
Evidentiary weight: Weaker evidence. Read with the caveat below.
Chain of custody: Supplier despatch → laboratory direct (courier, cold pack, 8 d) → assay. Submitter did not handle the vial.
Assay date: 11 Feb 2026
Submitted to the index: 13 Feb 2026
Laboratory: Medutest, Ljubljana, Slovenia
Method basis: 25 min gradient · unit-resolution MS
Verification status: IDENTITY CONSISTENT

What this report does not establish

That the compound is not a near-isobaric alternative. Identity was confirmed at unit mass resolution, which cannot exclude species differing by 1 or 2 Da. The specific alternatives not excluded are named in the identity block above.
That the material is free of bacterial endotoxin. Endotoxin was not measured. No chromatographic result bears on it.
That the material is sterile. Sterility was not tested.
That any other vial in the same lot has the same composition. One vial was tested. Within-lot vial-to-vial variation in this index has a median of 0.28 pp and a 90th percentile of 0.74 pp.
That any other lot from the same supplier has the same composition. Batch-to-batch variation is larger than within-batch variation for every supplier here.
That the material is suitable for administration to a human or an animal. These are research compounds. No result on this site is a safety assessment and the index takes no position on use.
That the material was manufactured by the supplier that sold it. Contract synthesis is normal in this market and twenty-nine batches in the index fingerprint to a bulk from a different company than the one named on the label.

Section 6

Annotations

No annotations on this record. Annotations are short signed technical comments from index contributors; see how to contribute.

Section 7

Related records

Same batch — lot KP-2511-K4263 n=9

Report	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Flags	Result
AX-2026-042972	KP-2511-K4263	Janoshik	2026-Q1	96.65	3.75	107.2	Supplier-supplied	2	MARGINAL
AX-2026-042973	KP-2511-K4263	Nordanalyt	2026-Q1	97.08	3.64	105.1	Supplier-supplied	2	MARGINAL
AX-2026-042974	KP-2511-K4263	Janoshik	2026-Q1	97.05	3.63	99.2	Buyer-sourced	2	MARGINAL
AX-2026-042975	KP-2511-K4263	Janoshik	2026-Q1	96.71	3.37	92.7	Supplier-supplied	2	MARGINAL
AX-2026-042977	KP-2511-K4263	Janoshik	2026-Q1	97.12	3.55	106.1	Supplier-supplied	2	MARGINAL
AX-2026-042978	KP-2511-K4263	Nordanalyt	2026-Q1	97.67	3.30	—	Supplier-supplied	2	MARGINAL
AX-2026-042979	KP-2511-K4263	Medutest	2026-Q1	97.28	3.97	98.5	Supplier-supplied	2	MARGINAL
AX-2026-042980	KP-2511-K4263	Janoshik	2026-Q1	97.23	4.39	—	Supplier-supplied	2	MARGINAL

Batch rollup and reproducibility assessment →

Cross-sections

Other recent Retatrutide records in the index.
Report	Supplier	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Flags	Result
AX-2026-043029	KP	KP-2607-H5219	Medutest	2026-Q3	95.45	5.71	—	Supplier-supplied	2	FAIL
AX-2026-043030	KP	KP-2607-H5219	Kestrel	2026-Q3	95.97	6.95	97.1	Supplier-supplied	2	FAIL
AX-2026-041453	QYB	QYB-2604-B5660	VendorInvestigate	2026-Q3	98.02	2.55	—	Buyer-sourced	1	MARGINAL
AX-2026-041454	QYB	QYB-2604-B5660	Janoshik	2026-Q3	98.84	2.77	—	Supplier-supplied	1	MARGINAL
AX-2026-041538	QYB	QYB-2602-G6308	Medutest	2026-Q3	98.50	2.85	—	Supplier-supplied	2	MARGINAL
AX-2026-041456	QYB	QYB-2604-B5660	Janoshik	2026-Q3	98.23	3.24	—	Supplier-supplied	1	MARGINAL
AX-2026-041452	QYB	QYB-2604-B5660	Nordanalyt	2026-Q3	98.50	3.36	—	Supplier-supplied	1	MARGINAL
AX-2026-043039	KP	KP-2607-H5219	Janoshik	2026-Q3	96.14	5.62	—	Supplier-supplied	2	FAIL

Other recent KP records in the index.
Report	Compound	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Flags	Result
AX-2026-043029	Retatrutide	KP-2607-H5219	Medutest	2026-Q3	95.45	5.71	—	Supplier-supplied	2	FAIL
AX-2026-043030	Retatrutide	KP-2607-H5219	Kestrel	2026-Q3	95.97	6.95	97.1	Supplier-supplied	2	FAIL
AX-2026-043106	Tirzepatide	KP-2608-D5921	PeptideMeter	2026-Q3	98.90	5.45	105.4	Supplier-supplied	2	MARGINAL
AX-2026-043108	Tirzepatide	KP-2608-D5921	Janoshik	2026-Q3	99.70	5.45	—	Supplier-supplied	2	MARGINAL
AX-2026-043039	Retatrutide	KP-2607-H5219	Janoshik	2026-Q3	96.14	5.62	—	Supplier-supplied	2	FAIL
AX-2026-043100	Tirzepatide	KP-2608-D5921	VendorInvestigate	2026-Q3	98.27	5.31	94.4	Buyer-sourced	2	MARGINAL
AX-2026-043090	Ipamorelin	KP-2606-D5887	Janoshik	2026-Q3	98.18	3.07	101.2	Laboratory-retained	1	FAIL
AX-2026-043028	Retatrutide	KP-2607-H5219	Janoshik	2026-Q3	96.52	6.09	—	Supplier-supplied	2	MARGINAL