AX-2024-004362

L-Glutathione (reduced) · 200 mg declared · Flourishglobal Peptide Biotech (Chengdu) Co., Ltd. · lot FGP-2408-K8560

MARGINALMETHOD LIMITED

Report ID: AX-2024-004362
Compound: L-Glutathione (reduced)
Compound class: Short bioregulator peptides
Supplier: FGP — Flourishglobal Peptide Biotech (Chengdu) Co., Ltd.
Batch / lot: FGP-2408-K8560
Declared label claim: 200mg
Laboratory: PeptideMeter
Assay date: 12 Aug 2024
Submitted: 24 Aug 2024
Quarter: 2024-Q3
Submitter: e.almeida
Sample provenance: Buyer-sourced

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	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 — glutathione disulfide (GSSG, +305 Da)	0.05	% 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)	307.0836	Da	—	NOT TESTED
Mass accuracy	observed vs theoretical	-0.8	ppm	± 20	PASS
Total peptide content	by difference from the gravimetric mass balance	92.38	%w/w	—	NOT TESTED
Target-compound content	total peptide content × purity	92.32	%w/w	—	NOT TESTED
Gross fill (as weighed)	five-place balance, under nitrogen	193.89	mg	200 mg declared	NOT TESTED
Recovered target peptide	gross fill × target content	178.999	mg	200 mg claim	NOT TESTED
Recovery against label claim	recovered ÷ claim	89.5	%	90.0 – 110.0	FAIL
Water content	Karl Fischer, coulometric, duplicate	6.79	%	≤ 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/	0.83	%	—	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, colourless, no visible particulates	—	clear, no visible particulates	PASS
pH (reconstituted, 1 mg/mL)	potentiometric, two-point calibration	7.85	—	2.5 – 8.0	PASS
Retention time (observed)	RP-HPLC, 28 min gradient	4.03	min	4.02 ± 0.20 (normalised)	PASS
Peak asymmetry (10 % height)	Ph. Eur. 2.2.46	1.01	—	0.80 – 1.50	PASS
Plate count, main peak	N = 5.54 (t/w½)²	66,674	—	≥ 20,000	PASS
Resolution to nearest impurity	vs γ-Glu-Cys (−57 Da)	2.63	—	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 66,674, and skew follows the reported asymmetry factor of 1.01. 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 0.05 % 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	L-Glutathione (reduced) — main peak	4.03	4,856,908	99.93	—
2	glutathione disulfide (GSSG, +305 Da)	4.52	2,430	0.05	+304.984
3	γ-Glu-Cys (−57 Da)	3.86	972	0.02	-57.021
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 307.0836 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	308.0909	-0.0002	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	6.79
Counter-ion	none expected	0.00
Residual solvent + inorganic residue	estimated	0.83
Total peptide content	by difference	92.38
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)	99.90	99.93	divergence +0.03 pp vs batch median
Total impurities (% area)	0.10	0.07
Largest single impurity (% area)	0.05	0.05
Water (%)	6.3	6.79
Counter-ion (%)	4.4	N/A
Peptide content (%w/w)	88.7	92.38
Endotoxin (EU/mg)	not stated	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: Domestic warehouse despatch → submitter (2–8 °C, 19 d) → laboratory (courier, cold pack, 12 d) → assay.
Assay date: 12 Aug 2024
Submitted to the index: 24 Aug 2024
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 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.

sodium_adduct24 Aug 2024

Adduct bookkeeping on this one is tidy. The sodium series is present at the expected intensity ratio and has not been counted as an impurity, which happens more often than it should.

ppm_error24 Aug 2024

Well inside class limit. Worth noting that the class limits are set by mass rather than globally, because the same ppm is a different number of daltons at 340 and at 4,800.

price_per_mg24 Aug 2024

A retail purchase carries a price, which makes cost per milligram of recovered peptide computable. That is the comparison a buyer actually needs and it exists only for this provenance class.

Section 7

Related records

Same batch — lot FGP-2408-K8560 n=2

Report	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Flags	Result
AX-2024-004363	FGP-2408-K8560	Janoshik	2024-Q3	99.80	6.89	100.7	Buyer-sourced	0	PASS

Batch rollup and reproducibility assessment →

Cross-sections

All L-Glutathione (reduced) records n=129
All FGP records n=200
All PeptideMeter records n=1116
All 2024-Q3 records n=464
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 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