AX-2025-020035 · Retatrutide · ERP lot ERP-2506-C7220

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, 15 min gradient, 214 nm	98.54	% area	≥ 96.5	PASS
Total impurities	RP-HPLC, sum of reported peaks	1.46	% area	≤ 3.5	PASS
Largest single impurity	RP-HPLC — des-Aib20 analogue	0.72	% area	≤ 1.00	PASS
Identity — theoretical monoisotopic mass	calculated from molecular formula	4728.4871	Da	—	NOT TESTED
Identity — observed monoisotopic mass	LC-MS, unit resolution (single quadrupole)	4728.4039	Da	—	NOT TESTED
Mass accuracy	observed vs theoretical	-17.6	ppm	± 15	FAIL
Peptide content	not ordered on this submission	not determined	—	required to check label claim	NOT TESTED
Water content	Karl Fischer, coulometric, duplicate	4.95	%	≤ 8.0	PASS
Counter-ion (TFA)	anion-exchange ion chromatography	8.66	%	≤ 12.0	PASS
Residual solvent + inorganic residue	estimated — see /methods/residual-solvents-q3c/	0.79	%	—	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	3.69	—	2.5 – 8.0	PASS
Retention time (observed)	RP-HPLC, 15 min gradient	11.32	min	11.18 ± 0.50 (normalised)	PASS
Peak asymmetry (10 % height)	Ph. Eur. 2.2.46	1.43	—	0.80 – 1.50	PASS
Plate count, main peak	N = 5.54 (t/w½)²	49,812	—	≥ 20,000	PASS
Resolution to nearest impurity	vs [D-Aib2]-diastereomer	0.53	—	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, 15 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 49,812, and skew follows the reported asymmetry factor of 1.43. 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 0.72 % impurity against a 98.54 % 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	11.32	4,789,349	98.54	—
2	des-Aib20 analogue	11.10	34,994	0.72	-85.053
3	aspartimide (−18 Da)	11.68	18,469	0.38	-18.011
4	truncated (5-39)	10.36	7,776	0.16	-428.201
5	[D-Aib2]-diastereomer	11.21	6,318	0.13	0.000
6	oxidised Trp (+16 Da)	10.99	2,430	0.05	+15.995
7	retatrutide dimer	13.38	972	0.02	+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 4728.4039 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	676.4935	-0.0119	8.2
6+	789.0885	789.0746	-0.0139	53.4
5+	946.7047	946.6881	-0.0166	100.0
4+	1183.1291	1183.1083	-0.0208	57.4
3+	1577.1696	1577.1419	-0.0277	7.6

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.

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)	99.0	98.54	divergence +0.46 pp vs batch median
Total impurities (% area)	1.00	1.46
Largest single impurity (% area)	0.65	0.72
Water (%)	not stated	4.95
Counter-ion (%)	not stated	8.66
Peptide content (%w/w)	91.7	not determined
Endotoxin (EU/mg)	0.52	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: Buyer-sourced
Evidentiary weight: Strongest available evidence in this index.
Chain of custody: Retail purchase → submitter (2–8 °C, 34 d) → laboratory (courier, ambient, 9 d) → assay.
Assay date: 08 Aug 2025
Submitted to the index: 23 Aug 2025
Laboratory: Kestrel Bioanalytical, Melbourne, Australia
Method basis: 15 min gradient · unit-resolution MS
Verification status: METHOD LIMITED

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 mass-identical impurities are absent. The gradient used is shorter than the index reference method and does not resolve the diastereomers named in the compound fingerprint. The purity figure is an upper bound.
How much of the named compound is in the vial. Peptide content was not determined, so recovered mass cannot be calculated and the label claim cannot be checked.
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 ERP-2506-C7220 n=3

Report	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Flags	Result
AX-2025-020033	ERP-2506-C7220	Janoshik	2025-Q3	98.55	4.97	101.4	Supplier-supplied	2	MARGINAL
AX-2025-020034	ERP-2506-C7220	Janoshik	2025-Q3	98.26	5.59	100.9	Supplier-supplied	3	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 ERP records in the index.
Report	Compound	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Flags	Result
AX-2026-042574	TB-500	ERP-2605-S8022	VendorInvestigate	2026-Q3	99.54	2.91	96.4	Buyer-sourced	1	MARGINAL
AX-2026-042535	Tesamorelin	ERP-2604-W7280	Janoshik	2026-Q3	99.19	3.89	92.7	Supplier-supplied	1	MARGINAL
AX-2026-042577	TB-500	ERP-2605-S8022	Janoshik	2026-Q3	99.51	3.45	—	Supplier-supplied	1	MARGINAL
AX-2026-042542	Tesamorelin	ERP-2604-W7280	Janoshik	2026-Q3	98.54	4.58	103.1	Supplier-supplied	2	FAIL
AX-2026-042547	Survodutide	ERP-2605-E7682	PeptideMeter	2026-Q3	98.25	5.44	93.0	Supplier-supplied	1	MARGINAL
AX-2026-042540	Tesamorelin	ERP-2604-W7280	Kestrel	2026-Q3	99.72	3.47	103.2	Supplier-supplied	1	MARGINAL
AX-2026-042575	TB-500	ERP-2605-S8022	Janoshik	2026-Q3	99.93	3.36	95.5	Supplier-supplied	0	PASS
AX-2026-042539	Tesamorelin	ERP-2604-W7280	Janoshik	2026-Q3	98.77	4.30	89.9	Buyer-sourced	2	MARGINAL