AX-2026-043623 · L-Glutathione (reduced) · WXT lot WXT-2605-B5720

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, 32 min gradient, 214 nm	98.02	% area	≥ 98.5	FAIL
Total impurities	RP-HPLC, sum of reported peaks	1.98	% 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)	307.0844	Da	—	NOT TESTED
Mass accuracy	observed vs theoretical	+1.9	ppm	± 20	PASS
Total peptide content	by difference from the gravimetric mass balance	92.35	%w/w	—	NOT TESTED
Target-compound content	total peptide content × purity	90.52	%w/w	—	NOT TESTED
Gross fill (as weighed)	five-place balance, under nitrogen	704.07	mg	600 mg declared	NOT TESTED
Recovered target peptide	gross fill × target content	637.324	mg	600 mg claim	NOT TESTED
Recovery against label claim	recovered ÷ claim	106.2	%	90.0 – 110.0	PASS
Water content	Karl Fischer, coulometric, duplicate	6.73	%	≤ 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/	0.92	%	—	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	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	8.04	—	2.5 – 8.0	FAIL
Retention time (observed)	RP-HPLC, 32 min gradient	4.56	min	4.54 ± 0.20 (normalised)	PASS
Peak asymmetry (10 % height)	Ph. Eur. 2.2.46	1.18	—	0.80 – 1.50	PASS
Plate count, main peak	N = 5.54 (t/w½)²	75,819	—	≥ 20,000	PASS
Resolution to nearest impurity	vs S-sulfonate adduct (+80 Da)	2.20	—	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, 32 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 75,819, and skew follows the reported asymmetry factor of 1.18. 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 98.02 % 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	4.56	4,764,076	98.02	—
2	cysteinyl-glycine (−129 Da)	4.30	61,240	1.26	-129.043
3	glutathione disulfide (GSSG, +305 Da)	5.11	23,329	0.48	+304.984
4	γ-Glu-Cys (−57 Da)	4.37	6,804	0.14	-57.021
5	S-sulfonate adduct (+80 Da)	4.41	4,860	0.10	+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 307.0844 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	308.0917	0.0006	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	6.73
Counter-ion	none expected	0.00
Residual solvent + inorganic residue	estimated	0.92
Total peptide content	by difference	92.35
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)	98.0	98.02	divergence -0.10 pp vs batch median
Total impurities (% area)	2.00	1.98
Largest single impurity (% area)	not stated	1.26
Water (%)	not stated	6.73
Counter-ion (%)	not stated	N/A
Peptide content (%w/w)	91.7	92.35
Endotoxin (EU/mg)	0.72	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: Laboratory-retained
Evidentiary weight: Provenance documented, selection uncontrolled.
Chain of custody: Laboratory retained sample (−20 °C, 32 d since original receipt) → re-assay.
Assay date: 24 Aug 2026
Submitted to the index: 03 Sep 2026
Laboratory: VendorInvestigate, Riga, Latvia
Method basis: 32 min gradient · high-resolution MS
Verification status: METHOD LIMITED

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 3

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_integrator03 Sep 2026

Reporting threshold matters at this level. Peaks below threshold are excluded from the impurity total but included in the purity denominator, which biases 98.02 % upward by a systematic tenth or so. The gap here is larger than that.

quad_unit03 Sep 2026

The index grades identity by instrument class, not by the ppm figure alone: "confirmed" where the determination was made at high resolution, "consistent with" where it was not. The status block above says which applies to this record, and it is worth reading before the number.

median_not_mean03 Sep 2026

Aggregating declared figures across a supplier is a weaker exercise than aggregating measurements, because declarations inherit the template's quantisation. Medians are less disturbed by it than means.

Section 7

Related records

Same batch — lot WXT-2605-B5720 n=8

Report	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Flags	Result
AX-2026-043620	WXT-2605-B5720	Kestrel	2026-Q3	98.33	6.74	101.9	Buyer-sourced	1	FAIL
AX-2026-043621	WXT-2605-B5720	Kestrel	2026-Q3	98.63	6.51	105.3	Buyer-sourced	1	MARGINAL
AX-2026-043622	WXT-2605-B5720	Janoshik	2026-Q3	98.02	6.81	—	Buyer-sourced	1	FAIL
AX-2026-043624	WXT-2605-B5720	Nordanalyt	2026-Q3	98.18	6.95	105.3	Buyer-sourced	2	FAIL
AX-2026-043625	WXT-2605-B5720	Janoshik	2026-Q3	97.87	6.10	90.7	Buyer-sourced	1	FAIL
AX-2026-043626	WXT-2605-B5720	Medutest	2026-Q3	98.22	6.33	100.3	Buyer-sourced	1	FAIL
AX-2026-043627	WXT-2605-B5720	Janoshik	2026-Q3	97.96	6.08	92.3	Buyer-sourced	1	FAIL

Batch rollup and reproducibility assessment →

Cross-sections

All L-Glutathione (reduced) records n=140
All WXT records n=380
All VendorInvestigate records n=605
All 2026-Q3 records n=455
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-2026-041873	GSP	GSP-2607-N3316	Janoshik	2026-Q3	98.45	7.55	94.9	Buyer-sourced	1	FAIL
AX-2026-041870	GSP	GSP-2607-N3316	Nordanalyt	2026-Q3	98.68	7.65	90.5	Buyer-sourced	0	PASS
AX-2026-043627	WXT	WXT-2605-B5720	Janoshik	2026-Q3	97.96	6.08	92.3	Buyer-sourced	1	FAIL
AX-2026-043624	WXT	WXT-2605-B5720	Nordanalyt	2026-Q3	98.18	6.95	105.3	Buyer-sourced	2	FAIL
AX-2026-043622	WXT	WXT-2605-B5720	Janoshik	2026-Q3	98.02	6.81	—	Buyer-sourced	1	FAIL
AX-2026-041872	GSP	GSP-2607-N3316	Medutest	2026-Q3	98.50	7.78	—	Buyer-sourced	1	MARGINAL
AX-2026-041875	GSP	GSP-2607-N3316	Janoshik	2026-Q3	98.69	7.45	—	Buyer-sourced	0	PASS
AX-2026-041868	GSP	GSP-2607-N3316	Medutest	2026-Q3	98.36	7.87	—	Buyer-sourced	0	FAIL

Other recent WXT records in the index.
Report	Compound	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Flags	Result
AX-2026-043651	Pramlintide	WXT-2603-D6459	PeptideMeter	2026-Q3	98.21	4.97	101.6	Buyer-sourced	1	MARGINAL
AX-2026-043531	Leuprolide	WXT-2604-K4483	Medutest	2026-Q3	99.00	5.03	—	Buyer-sourced	0	PASS
AX-2026-043561	Semaglutide	WXT-2604-C5135	Janoshik	2026-Q3	96.96	4.22	91.3	Buyer-sourced	0	FAIL
AX-2026-043627	L-Glutathione (reduced)	WXT-2605-B5720	Janoshik	2026-Q3	97.96	6.08	92.3	Buyer-sourced	1	FAIL
AX-2026-043564	Semaglutide	WXT-2604-C5135	Janoshik	2026-Q3	97.15	4.44	104.7	Buyer-sourced	0	PASS
AX-2026-043533	Leuprolide	WXT-2604-K4483	PeptideMeter	2026-Q3	99.89	4.94	—	Supplier-supplied	0	PASS
AX-2026-043624	L-Glutathione (reduced)	WXT-2605-B5720	Nordanalyt	2026-Q3	98.18	6.95	105.3	Buyer-sourced	2	FAIL
AX-2026-043556	Semaglutide	WXT-2604-C5135	PeptideMeter	2026-Q3	97.56	4.35	89.6	Buyer-sourced	1	MARGINAL