AX-2026-043461

L-Glutathione (reduced) · 600 mg declared · WuXi TIDES (WuXi AppTec Testing Division) · lot WXT-2605-B5313

FAILMETHOD LIMITED

Report ID: AX-2026-043461
Compound: L-Glutathione (reduced)
Compound class: Short bioregulator peptides
Supplier: WXT — WuXi TIDES (WuXi AppTec Testing Division)
Batch / lot: WXT-2605-B5313
Declared label claim: 600mg
Laboratory: PeptideMeter
Assay date: 15 Jul 2026
Submitted: 05 Aug 2026
Quarter: 2026-Q3
Submitter: ad.ibarra
Sample provenance: Supplier-supplied

Section 1

Results

Measured against the index acceptance specification for the short bioregulator 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, 28 min gradient, 214 nm	97.39	% area	≥ 98.5	FAIL
Total impurities	RP-HPLC, sum of reported peaks	2.61	% area	≤ 1.5	FAIL
Largest single impurity	RP-HPLC — cysteinyl-glycine (−129 Da)	1.26	% area	≤ 1.00	FAIL
Identity — theoretical monoisotopic mass	calculated from molecular formula	307.0838	Da	—	NOT TESTED
Identity — observed monoisotopic mass	LC-MS, high resolution (ESI-TOF/QTOF)	307.0845	Da	—	NOT TESTED
Mass accuracy	observed vs theoretical	+2.2	ppm	± 20	PASS
Total peptide content	by difference from the gravimetric mass balance	92.86	%w/w	—	NOT TESTED
Target-compound content	total peptide content × purity	90.44	%w/w	—	NOT TESTED
Gross fill (as weighed)	five-place balance, under nitrogen	677.88	mg	600 mg declared	NOT TESTED
Recovered target peptide	gross fill × target content	613.075	mg	600 mg claim	NOT TESTED
Recovery against label claim	recovered ÷ claim	102.2	%	90.0 – 110.0	PASS
Water content	Karl Fischer, coulometric, duplicate	6.92	%	≤ 12.0	PASS
Counter-ion	no ionisable counter-ion expected	N/A	—	not applicable	NOT TESTED
Residual solvent + inorganic residue	estimated — see /methods/residual-solvents-q3c/	0.22	%	—	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	5.74	—	2.5 – 8.0	PASS
Retention time (observed)	RP-HPLC, 28 min gradient	4.09	min	4.02 ± 0.20 (normalised)	PASS
Peak asymmetry (10 % height)	Ph. Eur. 2.2.46	1.23	—	0.80 – 1.50	PASS
Plate count, main peak	N = 5.54 (t/w½)²	64,935	—	≥ 20,000	PASS
Resolution to nearest impurity	vs S-sulfonate adduct (+80 Da)	1.99	—	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 64,935, and skew follows the reported asymmetry factor of 1.23. 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 1.26 % impurity against a 97.39 % 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	L-Glutathione (reduced) — main peak	4.09	4,733,456	97.39	—
2	cysteinyl-glycine (−129 Da)	3.87	61,240	1.26	-129.043
3	γ-Glu-Cys (−57 Da)	3.92	37,424	0.77	-57.021
4	glutathione disulfide (GSSG, +305 Da)	4.58	19,441	0.40	+304.984
5	S-sulfonate adduct (+80 Da)	3.96	8,749	0.18	+79.957
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 307.0838 Da, computed from C10H17N3O6S. 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 307.0845 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 (%)
1+	308.0911	308.0918	0.0007	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	6.92
Counter-ion	none expected	0.00
Residual solvent + inorganic residue	estimated	0.22
Total peptide content	by difference	92.86
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)	97.87	97.39	divergence +0.48 pp vs batch median
Total impurities (% area)	not stated	2.61
Largest single impurity (% area)	not stated	1.26
Water (%)	not stated	6.92
Counter-ion (%)	not stated	N/A
Peptide content (%w/w)	not stated	92.86
Endotoxin (EU/mg)	not stated	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: Supplier-supplied
Evidentiary weight: Weaker evidence. Read with the caveat below.
Chain of custody: Supplier despatch → laboratory direct (courier, cold pack, 3 d) → assay. Submitter did not handle the vial.
Assay date: 15 Jul 2026
Submitted to the index: 05 Aug 2026
Laboratory: PeptideMeter, Tallinn, Estonia
Method basis: 28 min gradient · high-resolution MS
Verification status: METHOD LIMITED

What this report does not establish

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 WXT-2605-B5313 n=1

This is the only report on this lot. One report is not a batch characterisation.

Batch rollup and reproducibility assessment →

Cross-sections

All L-Glutathione (reduced) records n=122
All WXT records n=353
All PeptideMeter records n=1107
All 2026-Q3 records n=453
L-Glutathione (reduced) by supplier
L-Glutathione (reduced) impurity profile

Other recent L-Glutathione (reduced) records in the index.
Report	Supplier	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Flags	Result
AX-2026-043166	GL Biochem	GLBI-2606-S7722	PeptideMeter	2026-Q3	99.26	8.52	107.1	Supplier-supplied	1	MARGINAL
AX-2026-042932	MKM	MKM-2511-F2902	Janoshik	2026-Q2	98.57	8.41	92.9	Supplier-supplied	1	MARGINAL
AX-2026-043399	WXT	WXT-2512-P4300	PeptideMeter	2026-Q2	98.07	8.72	—	Supplier-supplied	1	FAIL
AX-2026-042337	HJ	HJ-2511-F3082	Janoshik	2026-Q2	99.93	7.58	—	Supplier-supplied	0	PASS
AX-2026-042930	MKM	MKM-2511-F2902	Janoshik	2026-Q2	98.42	7.82	97.4	Supplier-supplied	1	FAIL
AX-2026-042336	HJ	HJ-2511-F3082	Janoshik	2026-Q2	99.93	7.34	—	Supplier-supplied	0	PASS
AX-2026-042338	HJ	HJ-2511-F3082	Kestrel	2026-Q2	99.93	6.73	—	Supplier-supplied	0	PASS
AX-2026-042937	MKM	MKM-2602-X3845	PeptideMeter	2026-Q2	98.59	8.86	—	Supplier-supplied	0	PASS

Other recent WXT records in the index.
Report	Compound	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Flags	Result
AX-2026-043488	Pramlintide	WXT-2603-D6052	Janoshik	2026-Q3	97.87	4.37	—	Supplier-supplied	1	MARGINAL
AX-2026-043406	Semaglutide	WXT-2604-C4728	Janoshik	2026-Q3	97.24	4.65	—	Supplier-supplied	1	MARGINAL
AX-2026-043421	Sermorelin	WXT-2608-P4867	Janoshik	2026-Q3	98.15	3.09	—	Supplier-supplied	0	PASS
AX-2026-043420	Sermorelin	WXT-2608-P4867	Medutest	2026-Q3	98.62	3.07	96.4	Supplier-supplied	0	PASS
AX-2026-043423	Sermorelin	WXT-2608-P4867	Janoshik	2026-Q3	98.28	3.86	98.5	Buyer-sourced	0	PASS
AX-2026-043401	Semaglutide	WXT-2604-C4728	Medutest	2026-Q3	97.70	4.78	91.5	Supplier-supplied	1	MARGINAL
AX-2026-043400	Semaglutide	WXT-2604-C4728	Nordanalyt	2026-Q3	96.86	4.11	106.4	Laboratory-retained	1	FAIL
AX-2026-043422	Sermorelin	WXT-2608-P4867	Medutest	2026-Q3	98.35	3.59	—	Supplier-supplied	1	MARGINAL