AX-2026-042401 · Retatrutide · Homopeptide lot HOMO-2601-J3763

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, 28 min gradient, 214 nm	99.00	% area	≥ 96.5	PASS
Total impurities	RP-HPLC, sum of reported peaks	1.00	% area	≤ 3.5	PASS
Largest single impurity	RP-HPLC — truncated (5-39)	0.59	% area	≤ 1.00	PASS
Identity — theoretical monoisotopic mass	calculated from molecular formula	4728.4871	Da	—	NOT TESTED
Identity — observed monoisotopic mass	LC-MS, high resolution (ESI-TOF/QTOF)	4728.4880	Da	—	NOT TESTED
Mass accuracy	observed vs theoretical	+0.2	ppm	± 15	PASS
Total peptide content	by difference from the gravimetric mass balance	88.74	%w/w	—	NOT TESTED
Target-compound content	total peptide content × purity	87.85	%w/w	—	NOT TESTED
Gross fill (as weighed)	five-place balance, under nitrogen	5.25	mg	5 mg declared	NOT TESTED
Recovered target peptide	gross fill × target content	4.612	mg	5 mg claim	NOT TESTED
Recovery against label claim	recovered ÷ claim	92.2	%	90.0 – 110.0	PASS
Water content	Karl Fischer, coulometric, duplicate	4.84	%	≤ 8.0	PASS
Counter-ion (TFA)	anion-exchange ion chromatography	5.53	%	≤ 12.0	PASS
Residual solvent + inorganic residue	estimated — see /methods/residual-solvents-q3c/	0.89	%	—	NOT TESTED
Endotoxin	kinetic chromogenic LAL	3.15	EU/mg	≤ 5.0	PASS
Sterility	not ordered on this submission	not determined	—	no growth	NOT TESTED
Appearance	visual, diffuse light, black and white background	White cake, partially collapsed	—	white to off-white intact cake	FAIL
Reconstitution clarity	reconstituted per submitter procedure	Faint haze, clearing on standing	—	clear, no visible particulates	FAIL
pH (reconstituted, 1 mg/mL)	potentiometric, two-point calibration	3.14	—	2.5 – 8.0	PASS
Retention time (observed)	RP-HPLC, 28 min gradient	19.43	min	19.44 ± 0.50 (normalised)	PASS
Peak asymmetry (10 % height)	Ph. Eur. 2.2.46	1.08	—	0.80 – 1.50	PASS
Plate count, main peak	N = 5.54 (t/w½)²	44,181	—	≥ 20,000	PASS
Resolution to nearest impurity	vs [D-Aib2]-diastereomer	0.54	—	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, 28 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 44,181, and skew follows the reported asymmetry factor of 1.08. 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 0.59 % impurity against a 99.00 % 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	19.43	4,811,707	99.00	—
2	truncated (5-39)	17.64	28,676	0.59	-428.201
3	retatrutide dimer	23.28	11,665	0.24	+4728.487
4	incomplete Fmoc removal (+222 Da)	21.68	5,346	0.11	+222.068
5	C18 diacid regioisomer	19.97	1,458	0.03	0.000
6	[D-Aib2]-diastereomer	19.22	1,458	0.03	0.000
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, high-resolution instrument. Sticks are placed at m/z = (M + z × 1.007276)/z for the observed neutral mass of 4728.4880 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	676.5056	0.0002	8.4
6+	789.0885	789.0886	0.0001	55.6
5+	946.7047	946.7049	0.0002	100.0
4+	1183.1291	1183.1293	0.0002	54.7
3+	1577.1696	1577.1699	0.0003	8.4

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	4.84
Counter-ion (TFA)	ion chromatography	5.53
Residual solvent + inorganic residue	estimated	0.89
Total peptide content	by difference	88.74
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)	99.32	99.00	divergence +0.28 pp vs batch median
Total impurities (% area)	0.68	1.00
Largest single impurity (% area)	0.40	0.59
Water (%)	3.6	4.84
Counter-ion (%)	not stated	5.53
Peptide content (%w/w)	91.6	88.74
Endotoxin (EU/mg)	3.48	3.15
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: Domestic warehouse despatch → submitter (2–8 °C, 11 d) → laboratory (courier, cold pack, 10 d) → assay.
Assay date: 19 Mar 2026
Submitted to the index: 29 Mar 2026
Laboratory: PeptideMeter, Tallinn, Estonia
Method basis: 28 min gradient · high-resolution MS
Verification status: VERIFIED

What this report does not establish

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 2

Signed technical comments from index contributors. Not a discussion forum — annotations question or contextualise the result, and the data team replies where a reply is warranted.

isotope_cluster29 Mar 2026

The isotope pattern is consistent with the elemental composition of Retatrutide. That is a second, independent check on identity and it agrees with the mass.

tbu_residual29 Mar 2026

No +56 Da satellite in the envelope, which is the residual-protection signature. Its absence is worth as much as the parent mass being right.

Section 7

Related records

Same batch — lot HOMO-2601-J3763 n=16

Report	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Flags	Result
AX-2026-042395	HOMO-2601-J3763	Janoshik	2026-Q1	99.12	5.41	—	Buyer-sourced	0	PASS
AX-2026-042396	HOMO-2601-J3763	PeptideMeter	2026-Q1	99.41	5.23	103.5	Supplier-supplied	0	PASS
AX-2026-042397	HOMO-2601-J3763	VendorInvestigate	2026-Q1	98.82	5.32	—	Buyer-sourced	0	PASS
AX-2026-042398	HOMO-2601-J3763	Nordanalyt	2026-Q1	98.95	5.44	94.2	Buyer-sourced	1	FAIL
AX-2026-042399	HOMO-2601-J3763	Janoshik	2026-Q1	99.03	5.36	94.0	Supplier-supplied	0	PASS
AX-2026-042400	HOMO-2601-J3763	Janoshik	2026-Q1	99.23	4.74	—	Buyer-sourced	0	PASS
AX-2026-042402	HOMO-2601-J3763	Janoshik	2026-Q1	99.39	4.43	—	Buyer-sourced	0	PASS
AX-2026-042403	HOMO-2601-J3763	Janoshik	2026-Q1	98.88	5.12	103.3	Buyer-sourced	0	PASS
AX-2026-042404	HOMO-2601-J3763	Nordanalyt	2026-Q1	98.90	5.30	93.4	Buyer-sourced	0	PASS
AX-2026-042405	HOMO-2601-J3763	Janoshik	2026-Q1	98.89	4.02	99.9	Buyer-sourced	0	PASS
AX-2026-042406	HOMO-2601-J3763	Janoshik	2026-Q1	99.04	5.06	90.8	Buyer-sourced	0	PASS
AX-2026-042407	HOMO-2601-J3763	VendorInvestigate	2026-Q1	98.99	4.95	90.8	Buyer-sourced	0	PASS
AX-2026-042408	HOMO-2601-J3763	VendorInvestigate	2026-Q1	99.23	4.92	93.9	Laboratory-retained	0	PASS
AX-2026-042409	HOMO-2601-J3763	PeptideMeter	2026-Q1	99.20	4.53	91.7	Buyer-sourced	1	FAIL
AX-2026-042410	HOMO-2601-J3763	Medutest	2026-Q1	99.17	5.59	96.5	Buyer-sourced	0	PASS

Batch rollup and reproducibility assessment →

Cross-sections

Other recent Retatrutide records in the index.
Report	Supplier	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Result
AX-2026-042437	Homopeptide	HOMO-2605-V4718	Nordanalyt	2026-Q3	98.68	3.67	102.8	Buyer-sourced	PASS
AX-2026-043095	KP	KP-2607-H5774	Janoshik	2026-Q3	95.81	5.48	105.2	Buyer-sourced	FAIL
AX-2026-042282	TFC	TFC-2608-J1156	Janoshik	2026-Q3	98.54	4.27	—	Buyer-sourced	PASS
AX-2026-043094	KP	KP-2607-H5774	PeptideMeter	2026-Q3	96.32	6.40	—	Buyer-sourced	FAIL
AX-2026-042441	Homopeptide	HOMO-2605-V4718	Medutest	2026-Q3	98.93	4.22	—	Buyer-sourced	PASS
AX-2026-041427	QYB	QYB-2604-B4920	PeptideMeter	2026-Q3	97.93	2.45	101.7	Buyer-sourced	PASS
AX-2026-041786	ASY	ASY-{CAT}-2288	VendorInvestigate	2026-Q3	98.78	6.59	—	Buyer-sourced	PASS
AX-2026-041428	QYB	QYB-2604-B4920	Janoshik	2026-Q3	98.35	3.20	—	Laboratory-retained	PASS

Other recent Homopeptide records in the index.
Report	Compound	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Result
AX-2026-042437	Retatrutide	HOMO-2605-V4718	Nordanalyt	2026-Q3	98.68	3.67	102.8	Buyer-sourced	PASS
AX-2026-042424	Semaglutide	HOMO-2604-X3806	PeptideMeter	2026-Q3	98.85	4.87	92.0	Buyer-sourced	PASS
AX-2026-042503	IGF-1 LR3	HOMO-2607-P5131	Janoshik	2026-Q3	99.36	5.99	—	Buyer-sourced	PASS
AX-2026-042492	SS-31 (Elamipretide)	HOMO-2604-D5484	Medutest	2026-Q3	99.93	2.40	—	Buyer-sourced	PASS
AX-2026-042491	SS-31 (Elamipretide)	HOMO-2604-D5484	Kestrel	2026-Q3	99.93	3.24	—	Supplier-supplied	PASS
AX-2026-042473	LL-37	HOMO-2602-G5165	Janoshik	2026-Q3	99.01	5.00	—	Buyer-sourced	PASS
AX-2026-042441	Retatrutide	HOMO-2605-V4718	Medutest	2026-Q3	98.93	4.22	—	Buyer-sourced	PASS
AX-2026-042474	LL-37	HOMO-2602-G5165	Janoshik	2026-Q3	99.18	5.44	—	Buyer-sourced	PASS