AX-2026-042760 · Melanotan II · GGPeps lot GGPE-2603-P1474

Section 1

Results

Measured against the index acceptance specification for the melanocortin-receptor peptides 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	99.43	% area	≥ 98.5	PASS
Total impurities	RP-HPLC, sum of reported peaks	0.57	% area	≤ 1.5	PASS
Largest single impurity	RP-HPLC — linear (open-lactam) precursor (+18 Da)	0.29	% area	≤ 1.00	PASS
Identity — theoretical monoisotopic mass	calculated from molecular formula	1023.5402	Da	—	NOT TESTED
Identity — observed monoisotopic mass	LC-MS, unit resolution (single quadrupole)	1023.5485	Da	—	NOT TESTED
Mass accuracy	observed vs theoretical	+8.1	ppm	± 15	PASS
Peptide content	not ordered on this submission	not determined	—	required to check label claim	NOT TESTED
Water content	Karl Fischer, coulometric, duplicate	7.02	%	≤ 8.0	PASS
Counter-ion (acetate)	anion-exchange ion chromatography	4.74	%	≤ 10.0	PASS
Residual solvent + inorganic residue	estimated — see /methods/residual-solvents-q3c/	0.22	%	—	NOT TESTED
Endotoxin	kinetic chromogenic LAL	0.69	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	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	5.88	—	2.5 – 8.0	PASS
Retention time (observed)	RP-HPLC, 25 min gradient	8.33	min	8.33 ± 0.25 (normalised)	PASS
Peak asymmetry (10 % height)	Ph. Eur. 2.2.46	1.07	—	0.80 – 1.50	PASS
Plate count, main peak	N = 5.54 (t/w½)²	36,187	—	≥ 20,000	PASS
Resolution to nearest impurity	vs oxidised Trp (+16 Da)	1.67	—	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 36,187, and skew follows the reported asymmetry factor of 1.07. 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 0.29 % impurity against a 99.43 % 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	Melanotan II — main peak	8.33	4,832,606	99.43	—
2	linear (open-lactam) precursor (+18 Da)	7.71	14,095	0.29	+18.011
3	MT-II dimer (head-to-tail)	10.29	8,749	0.18	+1023.540
4	oxidised Trp (+16 Da)	8.03	2,916	0.06	+15.995
5	des-acetyl MT-II (−42 Da)	7.93	1,944	0.04	-42.011
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 1023.5402 Da, computed from C50H69N15O9. 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 1023.5485 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 (%)
3+	342.1873	342.1901	0.0028	8.0
2+	512.7774	512.7815	0.0041	51.5
1+	1024.5475	1024.5558	0.0083	100.0

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)	99.10	99.43	divergence -0.14 pp vs batch median
Total impurities (% area)	0.90	0.57
Largest single impurity (% area)	0.42	0.29
Water (%)	6.6	7.02
Counter-ion (%)	not stated	4.74
Peptide content (%w/w)	not stated	not determined
Endotoxin (EU/mg)	not stated	0.69
Method stated on certificate	YES	—	column, gradient and wavelength given

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 → third-party forwarder (28 d) → laboratory (courier, cold pack, 3 d) → assay.
Assay date: 23 Jul 2026
Submitted to the index: 15 Aug 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.
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 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.

peak_integrator15 Aug 2026

99.43 % on Melanotan II sits at the top of what this index sees. Read it with the method: Medutest ran a 25 min gradient here, and the compound fingerprint names a mass-identical species that a shorter run folds into the main peak. On this gradient the figure is well founded.

shipping_temp15 Aug 2026

A data logger in the box would upgrade this record further. Custody is documented; temperature history is inferred, and inference is weaker than measurement.

Section 7

Related records

Same batch — lot GGPE-2603-P1474 n=6

Report	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Result
AX-2026-042755	GGPE-2603-P1474	Nordanalyt	2026-Q3	99.25	6.58	90.4	Buyer-sourced	PASS
AX-2026-042756	GGPE-2603-P1474	Nordanalyt	2026-Q3	99.17	7.04	—	Buyer-sourced	PASS
AX-2026-042757	GGPE-2603-P1474	Janoshik	2026-Q3	99.54	6.78	92.0	Buyer-sourced	PASS
AX-2026-042758	GGPE-2603-P1474	PeptideMeter	2026-Q3	99.23	6.96	—	Buyer-sourced	PASS
AX-2026-042759	GGPE-2603-P1474	Janoshik	2026-Q3	99.15	6.71	105.1	Buyer-sourced	PASS

Batch rollup and reproducibility assessment →

Cross-sections

Other recent Melanotan II records in the index.
Report	Supplier	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Flags	Result
AX-2026-042757	GGPeps	GGPE-2603-P1474	Janoshik	2026-Q3	99.54	6.78	92.0	Buyer-sourced	0	PASS
AX-2026-042756	GGPeps	GGPE-2603-P1474	Nordanalyt	2026-Q3	99.17	7.04	—	Buyer-sourced	0	PASS
AX-2026-042755	GGPeps	GGPE-2603-P1474	Nordanalyt	2026-Q3	99.25	6.58	90.4	Buyer-sourced	0	PASS
AX-2026-042758	GGPeps	GGPE-2603-P1474	PeptideMeter	2026-Q3	99.23	6.96	—	Buyer-sourced	0	PASS
AX-2026-042759	GGPeps	GGPE-2603-P1474	Janoshik	2026-Q3	99.15	6.71	105.1	Buyer-sourced	0	PASS
AX-2026-042168	JEEP	JEEP-2604-R9103	Nordanalyt	2026-Q2	99.40	5.71	—	Buyer-sourced	0	PASS
AX-2026-042164	JEEP	JEEP-2604-R9103	Janoshik	2026-Q2	99.54	5.23	—	Buyer-sourced	1	MARGINAL
AX-2026-042171	JEEP	JEEP-2604-R9103	Kestrel	2026-Q2	99.59	5.11	—	Buyer-sourced	0	PASS

Other recent GGPeps records in the index.
Report	Compound	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Result
AX-2026-042784	CJC-1295 (no DAC)	GGPE-2606-E1234	Medutest	2026-Q3	98.27	4.55	—	Buyer-sourced	PASS
AX-2026-042786	CJC-1295 (no DAC)	GGPE-2606-E1234	Janoshik	2026-Q3	98.22	3.77	—	Buyer-sourced	PASS
AX-2026-042858	Selank	GGPE-2603-J2447	VendorInvestigate	2026-Q3	98.87	8.85	99.4	Buyer-sourced	FAIL
AX-2026-042783	CJC-1295 (no DAC)	GGPE-2606-E1234	Janoshik	2026-Q3	98.22	4.45	90.6	Buyer-sourced	PASS
AX-2026-042757	Melanotan II	GGPE-2603-P1474	Janoshik	2026-Q3	99.54	6.78	92.0	Buyer-sourced	PASS
AX-2026-042785	CJC-1295 (no DAC)	GGPE-2606-E1234	PeptideMeter	2026-Q3	97.70	4.64	91.4	Buyer-sourced	FAIL
AX-2026-042756	Melanotan II	GGPE-2603-P1474	Nordanalyt	2026-Q3	99.17	7.04	—	Buyer-sourced	PASS
AX-2026-042755	Melanotan II	GGPE-2603-P1474	Nordanalyt	2026-Q3	99.25	6.58	90.4	Buyer-sourced	PASS