AX-2026-043275 · L-Glutathione (reduced) · CPC lot CPC-2602-D1499

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	98.36	% area	≥ 98.5	FAIL
Total impurities	RP-HPLC, sum of reported peaks	1.64	% area	≤ 1.5	FAIL
Largest single impurity	RP-HPLC — γ-Glu-Cys (−57 Da)	0.68	% area	≤ 1.00	PASS
Identity — theoretical monoisotopic mass	calculated from molecular formula	307.0838	Da	—	NOT TESTED
Identity — observed monoisotopic mass	LC-MS, high resolution (ESI-TOF/QTOF)	307.0851	Da	—	NOT TESTED
Mass accuracy	observed vs theoretical	+4.2	ppm	± 20	PASS
Total peptide content	by difference from the gravimetric mass balance	91.23	%w/w	—	NOT TESTED
Target-compound content	total peptide content × purity	89.73	%w/w	—	NOT TESTED
Gross fill (as weighed)	five-place balance, under nitrogen	1480.16	mg	1500 mg declared	NOT TESTED
Recovered target peptide	gross fill × target content	1328.148	mg	1500 mg claim	NOT TESTED
Recovery against label claim	recovered ÷ claim	88.5	%	90.0 – 110.0	FAIL
Water content	Karl Fischer, coulometric, duplicate	8.00	%	≤ 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/	0.77	%	—	NOT TESTED
Endotoxin	not ordered on this submission	not determined	—	≤ 5.0	NOT TESTED
Sterility	membrane filtration, USP <71>, 14 d	No growth at 14 d	—	no growth	PASS
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	6.49	—	2.5 – 8.0	PASS
Retention time (observed)	RP-HPLC, 28 min gradient	4.16	min	4.02 ± 0.20 (normalised)	PASS
Peak asymmetry (10 % height)	Ph. Eur. 2.2.46	1.31	—	0.80 – 1.50	PASS
Plate count, main peak	N = 5.54 (t/w½)²	81,866	—	≥ 20,000	PASS
Resolution to nearest impurity	vs S-sulfonate adduct (+80 Da)	2.19	—	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 81,866, and skew follows the reported asymmetry factor of 1.31. 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 0.68 % impurity against a 98.36 % 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	4.16	4,780,601	98.36	—
2	γ-Glu-Cys (−57 Da)	3.99	33,050	0.68	-57.021
3	glutathione disulfide (GSSG, +305 Da)	4.65	31,592	0.65	+304.984
4	S-sulfonate adduct (+80 Da)	4.03	8,749	0.18	+79.957
5	cysteinyl-glycine (−129 Da)	3.94	6,318	0.13	-129.043
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 307.0851 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	308.0924	0.0013	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	8.00
Counter-ion	none expected	0.00
Residual solvent + inorganic residue	estimated	0.77
Total peptide content	by difference	91.23
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)	98.48	98.36	divergence +0.12 pp vs batch median
Total impurities (% area)	not stated	1.64
Largest single impurity (% area)	not stated	0.68
Water (%)	6.9	8.00
Counter-ion (%)	not stated	N/A
Peptide content (%w/w)	not stated	91.23
Endotoxin (EU/mg)	0.48	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: Buyer-sourced
Evidentiary weight: Strongest available evidence in this index.
Chain of custody: Retail purchase → submitter (ambient, 30 d) → laboratory (courier, cold pack, 4 d) → assay.
Assay date: 12 Jan 2026
Submitted to the index: 07 Feb 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 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.

uncertainty_budget07 Feb 2026

The gap between 98.36 % and the class specification should be read against an expanded uncertainty of roughly ±0.5 pp. A shortfall inside that band is not a finding; a shortfall well outside it is.

ms_confirm07 Feb 2026

An orthogonal identity method on the same lot would make this the strongest class of record the index holds. Mass plus retention is already better than most.

bland_altman07 Feb 2026

Where two laboratories tested the same retail lot, the paired difference is a clean estimate of inter-lab bias with no selection term in it at all. Those pairs are the backbone of the agreement analysis.

Section 7

Related records

Same batch — lot CPC-2602-D1499 n=7

Report	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Result
AX-2026-043272	CPC-2602-D1499	Janoshik	2026-Q1	98.50	8.64	102.5	Supplier-supplied	PASS
AX-2026-043273	CPC-2602-D1499	Medutest	2026-Q1	98.72	7.46	95.6	Buyer-sourced	PASS
AX-2026-043274	CPC-2602-D1499	Janoshik	2026-Q1	98.31	8.10	—	Buyer-sourced	FAIL
AX-2026-043276	CPC-2602-D1499	Janoshik	2026-Q1	98.36	8.06	—	Buyer-sourced	FAIL
AX-2026-043277	CPC-2602-D1499	Nordanalyt	2026-Q1	98.25	7.94	—	Laboratory-retained	FAIL
AX-2026-043278	CPC-2602-D1499	Janoshik	2026-Q1	98.23	7.31	93.2	Buyer-sourced	FAIL

Batch rollup and reproducibility assessment →

Cross-sections

All L-Glutathione (reduced) records n=129
All CPC records n=227
All PeptideMeter records n=1116
All 2026-Q1 records n=806
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-2026-043429	WXT	WXT-2605-B3833	Nordanalyt	2026-Q3	98.48	6.58	96.9	Supplier-supplied	1	FAIL
AX-2026-043424	WXT	WXT-2605-B3833	PeptideMeter	2026-Q3	98.37	6.86	—	Buyer-sourced	0	FAIL
AX-2026-043166	GL Biochem	GLBI-2606-S7352	Janoshik	2026-Q3	99.01	8.84	105.4	Laboratory-retained	1	MARGINAL
AX-2026-043423	WXT	WXT-2605-B3833	Janoshik	2026-Q3	97.86	6.66	93.4	Buyer-sourced	0	FAIL
AX-2026-043426	WXT	WXT-2605-B3833	Kestrel	2026-Q3	98.83	6.32	—	Supplier-supplied	1	MARGINAL
AX-2026-043425	WXT	WXT-2605-B3833	Janoshik	2026-Q3	98.77	6.35	—	Supplier-supplied	1	MARGINAL
AX-2026-043431	WXT	WXT-2605-B3833	Nordanalyt	2026-Q3	97.94	6.18	—	Buyer-sourced	0	FAIL
AX-2026-043427	WXT	WXT-2605-B3833	Medutest	2026-Q3	97.67	6.08	—	Buyer-sourced	1	FAIL

Other recent CPC records in the index.
Report	Compound	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Flags	Result
AX-2026-043319	BPC-157	CPC-2602-W1610	Medutest	2026-Q3	98.82	2.88	103.5	Buyer-sourced	2	MARGINAL
AX-2026-043295	Liraglutide	CPC-2602-G9942	Janoshik	2026-Q3	97.34	5.17	106.3	Buyer-sourced	0	FAIL
AX-2026-043288	Tirzepatide	CPC-2607-L1516	Janoshik	2026-Q3	96.89	5.11	101.1	Laboratory-retained	0	FAIL
AX-2026-043327	N-Acetyl Semax Amide	CPC-2602-D1905	Nordanalyt	2026-Q3	99.05	5.67	90.6	Buyer-sourced	1	FAIL
AX-2026-043328	N-Acetyl Semax Amide	CPC-2602-D1905	Janoshik	2026-Q3	99.49	6.83	100.9	Supplier-supplied	0	PASS
AX-2026-043257	L-Carnosine	CPC-2603-G9615	VendorInvestigate	2026-Q3	98.20	10.41	102.2	Buyer-sourced	0	FAIL
AX-2026-043297	Liraglutide	CPC-2602-G9942	Janoshik	2026-Q3	97.01	4.95	103.5	Buyer-sourced	0	FAIL
AX-2026-043331	N-Acetyl Semax Amide	CPC-2602-D1905	Janoshik	2026-Q3	99.46	6.22	—	Supplier-supplied	0	PASS