AX-2025-019063 · MK-677 (Ibutamoren mesylate) · GSP lot GSP-2501-R2783

Section 1

Results

Measured against the index acceptance specification for the non-peptide adjuncts 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	99.93	% area	≥ 98.5	PASS
Total impurities	RP-HPLC, sum of reported peaks	0.07	% area	≤ 1.5	PASS
Largest single impurity	RP-HPLC — O-desmethyl metabolite analogue (−14 Da)	0.04	% area	≤ 1.00	PASS
Identity — theoretical monoisotopic mass	calculated from molecular formula	624.2181	Da	—	NOT TESTED
Identity — observed monoisotopic mass	LC-MS, unit resolution (single quadrupole)	624.2418	Da	—	NOT TESTED
Mass accuracy	observed vs theoretical	+37.9	ppm	± 10	FAIL
Peptide content	not ordered on this submission	not determined	—	required to check label claim	NOT TESTED
Water content	Karl Fischer, coulometric, duplicate	4.98	%	≤ 10.0	PASS
Counter-ion (mesylate)	anion-exchange ion chromatography	13.73	%	≤ 12.0	FAIL
Residual solvent + inorganic residue	estimated — see /methods/residual-solvents-q3c/	0.16	%	—	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	White lyophilised cake, intact	—	white to off-white intact cake	PASS
Reconstitution clarity	reconstituted per submitter procedure	Clear after 90 s gentle swirling, no particulates	—	clear, no visible particulates	PASS
pH (reconstituted, 1 mg/mL)	potentiometric, two-point calibration	5.51	—	2.5 – 8.0	PASS
Retention time (observed)	RP-HPLC, 25 min gradient	11.70	min	11.73 ± 0.30 (normalised)	PASS
Peak asymmetry (10 % height)	Ph. Eur. 2.2.46	1.02	—	0.80 – 1.50	PASS
Plate count, main peak	N = 5.54 (t/w½)²	89,263	—	≥ 20,000	PASS
Resolution to nearest impurity	vs spiroindane regioisomer	2.28	—	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 89,263, and skew follows the reported asymmetry factor of 1.02. 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 0.04 % impurity against a 99.93 % 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	MK-677 (Ibutamoren mesylate) — main peak	11.70	4,856,908	99.93	—
2	O-desmethyl metabolite analogue (−14 Da)	11.27	1,944	0.04	-14.016
3	spiroindane regioisomer	12.07	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 624.2181 Da, computed from C27H36N4O5S · CH4O3S. 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 624.2418 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 (%)
2+	313.1163	313.1282	0.0119	50.8
1+	625.2254	625.2491	0.0237	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)	100.0	99.93	divergence +0.53 pp vs batch median
Total impurities (% area)	not stated	0.07
Largest single impurity (% area)	not stated	0.04
Water (%)	4.6	4.98
Counter-ion (%)	3.3	13.73
Peptide content (%w/w)	91.5	not determined
Endotoxin (EU/mg)	0.87	not determined
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: Supplier-supplied
Evidentiary weight: Weaker evidence. Read with the caveat below.
Chain of custody: Supplier despatch → laboratory direct (courier, cold pack, 9 d) → assay. Submitter did not handle the vial.
Assay date: 04 Feb 2025
Submitted to the index: 16 Feb 2025
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 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 4

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.

c18_2p616 Feb 2025

Column chemistry flatters or punishes a figure like this. A core-shell column at this gradient resolves the close-eluting family that a fully porous 5 µm bed merges, so 99.93 % here is a harder number than the same figure from a coarser column.

lot_traceability16 Feb 2025

Lot GSP-2501-R2783 decodes to a manufacture date consistent with the custody chain above. Traceability plus 99.93 % is a complete story; either alone is half of one.

buyer_sourced16 Feb 2025

An independently purchased vial from the same lot would convert this record from indicative to decisive. Buyer-sourced material is roughly 87 % of the index and it should be all of it.

gc_headspace16 Feb 2025

Residual solvents sit in the same slot on the mass balance as counter-ion in a poorly specified certificate. Headspace gas chromatography separates the two and is rarely ordered.

Section 7

Related records

Same batch — lot GSP-2501-R2783 n=10

Report	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Result
AX-2025-019057	GSP-2501-R2783	Medutest	2025-Q1	99.45	6.07	96.3	Buyer-sourced	FAIL
AX-2025-019058	GSP-2501-R2783	Janoshik	2025-Q1	99.62	6.26	105.6	Laboratory-retained	FAIL
AX-2025-019059	GSP-2501-R2783	VendorInvestigate	2025-Q1	98.90	5.43	103.0	Buyer-sourced	FAIL
AX-2025-019060	GSP-2501-R2783	PeptideMeter	2025-Q1	99.43	5.64	90.3	Buyer-sourced	FAIL
AX-2025-019061	GSP-2501-R2783	Janoshik	2025-Q1	99.49	5.70	—	Buyer-sourced	FAIL
AX-2025-019062	GSP-2501-R2783	Medutest	2025-Q1	99.85	5.91	—	Buyer-sourced	FAIL
AX-2025-019064	GSP-2501-R2783	PeptideMeter	2025-Q1	99.41	5.84	—	Buyer-sourced	FAIL
AX-2025-019065	GSP-2501-R2783	Nordanalyt	2025-Q1	99.26	6.13	—	Laboratory-retained	FAIL
AX-2025-019066	GSP-2501-R2783	Medutest	2025-Q1	99.62	6.02	91.2	Buyer-sourced	FAIL

Batch rollup and reproducibility assessment →

Cross-sections

All MK-677 (Ibutamoren mesylate) records n=143
All GSP records n=180
All Medutest records n=934
All 2025-Q1 records n=672
MK-677 (Ibutamoren mesylate) by supplier
MK-677 (Ibutamoren mesylate) impurity profile

Other recent MK-677 (Ibutamoren mesylate) records in the index.
Report	Supplier	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Flags	Result
AX-2026-041633	FGP	FGP-2604-K8509	PeptideMeter	2026-Q2	99.81	4.91	96.2	Buyer-sourced	0	FAIL
AX-2026-041733	TFS	TFS-{CAT}-1096	PeptideMeter	2026-Q2	99.07	3.93	95.1	Laboratory-retained	0	FAIL
AX-2026-043468	BCH	BCH-2511-G5204	Medutest	2026-Q2	98.85	4.30	96.5	Buyer-sourced	1	FAIL
AX-2026-042647	SWB	SWB-2605-B7365	Nordanalyt	2026-Q2	99.28	2.86	93.1	Buyer-sourced	0	FAIL
AX-2026-041634	FGP	FGP-2604-K8509	PeptideMeter	2026-Q2	99.86	5.17	—	Buyer-sourced	0	FAIL
AX-2026-043469	BCH	BCH-2511-G5204	Medutest	2026-Q2	98.51	4.86	—	Buyer-sourced	1	FAIL
AX-2026-042648	SWB	SWB-2605-B7365	Janoshik	2026-Q2	99.93	2.60	96.9	Supplier-supplied	0	FAIL
AX-2026-041732	TFS	TFS-{CAT}-1096	Janoshik	2026-Q2	99.48	3.16	106.4	Buyer-sourced	0	FAIL

Other recent GSP records in the index.
Report	Compound	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Flags	Result
AX-2026-041831	Survodutide	GSP-2603-E3156	Kestrel	2026-Q3	99.91	5.50	93.2	Buyer-sourced	0	PASS
AX-2026-041836	Survodutide	GSP-2603-E3156	Janoshik	2026-Q3	98.65	5.34	90.3	Buyer-sourced	0	PASS
AX-2026-041837	Survodutide	GSP-2603-E3156	Janoshik	2026-Q3	98.33	5.37	—	Buyer-sourced	0	PASS
AX-2026-041833	Survodutide	GSP-2603-E3156	Janoshik	2026-Q3	98.08	4.91	99.3	Buyer-sourced	0	PASS
AX-2026-041832	Survodutide	GSP-2603-E3156	VendorInvestigate	2026-Q3	98.01	5.14	99.5	Buyer-sourced	0	PASS
AX-2026-041835	Survodutide	GSP-2603-E3156	Nordanalyt	2026-Q3	98.34	5.74	89.0	Buyer-sourced	1	MARGINAL
AX-2026-041834	Survodutide	GSP-2603-E3156	VendorInvestigate	2026-Q3	97.92	5.95	—	Buyer-sourced	0	PASS
AX-2026-041838	Survodutide	GSP-2603-E3156	PeptideMeter	2026-Q3	98.30	5.01	102.4	Buyer-sourced	0	PASS