AX-2026-041633

MK-677 (Ibutamoren mesylate) · 500 mg declared · Flourishglobal Peptide Biotech (Chengdu) Co., Ltd. · lot FGP-2604-K8509

FAILVERIFIED

Report ID: AX-2026-041633
Compound: MK-677 (Ibutamoren mesylate)
Compound class: Non-peptide adjuncts
Supplier: FGP — Flourishglobal Peptide Biotech (Chengdu) Co., Ltd.
Batch / lot: FGP-2604-K8509
Declared label claim: 500mg
Laboratory: PeptideMeter
Assay date: 11 Jun 2026
Submitted: 26 Jun 2026
Quarter: 2026-Q2
Submitter: Contributor #F-2358
Sample provenance: Buyer-sourced

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, 28 min gradient, 214 nm	99.81	% area	≥ 98.5	PASS
Total impurities	RP-HPLC, sum of reported peaks	0.19	% area	≤ 1.5	PASS
Largest single impurity	RP-HPLC — free base (des-mesylate, −96 Da)	0.12	% area	≤ 1.00	PASS
Identity — theoretical monoisotopic mass	calculated from molecular formula	624.2181	Da	—	NOT TESTED
Identity — observed monoisotopic mass	LC-MS, high resolution (ESI-TOF/QTOF)	624.2163	Da	—	NOT TESTED
Mass accuracy	observed vs theoretical	-2.9	ppm	± 10	PASS
Total peptide content	by difference from the gravimetric mass balance	78.71	%w/w	—	NOT TESTED
Target-compound content	total peptide content × purity	78.56	%w/w	—	NOT TESTED
Gross fill (as weighed)	five-place balance, under nitrogen	612.01	mg	500 mg declared	NOT TESTED
Recovered target peptide	gross fill × target content	480.795	mg	500 mg claim	NOT TESTED
Recovery against label claim	recovered ÷ claim	96.2	%	90.0 – 110.0	PASS
Water content	Karl Fischer, coulometric, duplicate	4.91	%	≤ 10.0	PASS
Counter-ion (mesylate)	anion-exchange ion chromatography	15.81	%	≤ 12.0	FAIL
Residual solvent + inorganic residue	estimated — see /methods/residual-solvents-q3c/	0.57	%	—	NOT TESTED
Endotoxin	kinetic chromogenic LAL	2.52	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, partial shrinkage from vial wall	—	white to off-white intact cake	FAIL
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	4.88	—	2.5 – 8.0	PASS
Retention time (observed)	RP-HPLC, 28 min gradient	13.03	min	13.01 ± 0.30 (normalised)	PASS
Peak asymmetry (10 % height)	Ph. Eur. 2.2.46	1.26	—	0.80 – 1.50	PASS
Plate count, main peak	N = 5.54 (t/w½)²	67,603	—	≥ 20,000	PASS
Resolution to nearest impurity	vs free base (des-mesylate, −96 Da)	0.18	—	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 67,603, and skew follows the reported asymmetry factor of 1.26. 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 0.12 % impurity against a 99.81 % 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	13.03	4,851,075	99.81	—
2	free base (des-mesylate, −96 Da)	13.07	5,832	0.12	-96.011
3	sulfonamide hydrolysis product (+18 Da)	12.23	1,944	0.04	+18.011
4	spiroindane regioisomer	13.44	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, high-resolution instrument. Sticks are placed at m/z = (M + z × 1.007276)/z for the observed neutral mass of 624.2163 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	313.1154	-0.0009	53.6
1+	625.2254	625.2236	-0.0018	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.

Component	Determination	%w/w of cake
Water	Karl Fischer	4.91
Counter-ion (mesylate)	ion chromatography	15.81
Residual solvent + inorganic residue	estimated	0.57
Total peptide content	by difference	78.71
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)	99.74	99.81	divergence -0.10 pp vs batch median
Total impurities (% area)	not stated	0.19
Largest single impurity (% area)	not stated	0.12
Water (%)	3.4	4.91
Counter-ion (%)	3.0	15.81
Peptide content (%w/w)	93.0	78.71
Endotoxin (EU/mg)	1.34	2.52
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 → submitter (2–8 °C, 14 d) → laboratory (courier, ambient, 11 d) → assay.
Assay date: 11 Jun 2026
Submitted to the index: 26 Jun 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 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.

scale_up_delta26 Jun 2026

Purity usually falls between gram and kilogram scale. A figure of 99.81 % on a commercial lot rather than a laboratory batch is the more informative version of this result.

ms_confirm26 Jun 2026

Mass, retention and impurity profile all agree on this record. Three independent constraints pointing the same way is the strongest identity evidence the index publishes.

buyer_sourced26 Jun 2026

Buyer-sourced through an ordinary retail order, so the supplier had no opportunity to select the vial. This is the provenance class the index weights and it is roughly 87 % of the dataset.

sample_vs_retail26 Jun 2026

Ordering under an unremarkable name and address is the whole method. It requires no cooperation from anybody and it produces the strongest evidence this index holds.

Section 7

Related records

Same batch — lot FGP-2604-K8509 n=2

Report	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Flags	Result
AX-2026-041634	FGP-2604-K8509	PeptideMeter	2026-Q2	99.86	5.17	—	Buyer-sourced	0	FAIL

Batch rollup and reproducibility assessment →

Cross-sections

All MK-677 (Ibutamoren mesylate) records n=143
All FGP records n=200
All PeptideMeter records n=1116
All 2026-Q2 records n=1126
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-2026-041733	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
AX-2026-041734	TFS	TFS-{CAT}-1096	PeptideMeter	2026-Q2	99.14	3.64	91.2	Buyer-sourced	0	FAIL

Other recent FGP records in the index.
Report	Compound	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Result
AX-2026-041643	Semaglutide	FGP-2602-M8547	Janoshik	2026-Q3	99.31	2.79	100.7	Buyer-sourced	PASS
AX-2026-041638	Semaglutide	FGP-2602-M8547	Janoshik	2026-Q3	99.40	2.75	105.8	Buyer-sourced	PASS
AX-2026-041641	Semaglutide	FGP-2602-M8547	PeptideMeter	2026-Q3	98.98	2.38	105.0	Buyer-sourced	PASS
AX-2026-041610	Tirzepatide	FGP-2603-L7753	Janoshik	2026-Q3	98.81	2.45	101.0	Buyer-sourced	PASS
AX-2026-041637	Semaglutide	FGP-2602-M8547	PeptideMeter	2026-Q3	99.40	2.83	—	Laboratory-retained	PASS
AX-2026-041642	Semaglutide	FGP-2602-M8547	PeptideMeter	2026-Q3	98.78	2.24	—	Buyer-sourced	PASS
AX-2026-041609	Tirzepatide	FGP-2603-L7753	Janoshik	2026-Q3	98.52	2.00	98.0	Buyer-sourced	PASS
AX-2026-041636	Semaglutide	FGP-2602-M8547	Nordanalyt	2026-Q3	99.39	2.17	—	Buyer-sourced	PASS