AX-2024-004502 · L-Glutathione (reduced) · FGP lot FGP-2405-E2221

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	99.25	% area	≥ 98.5	PASS
Total impurities	RP-HPLC, sum of reported peaks	0.75	% area	≤ 1.5	PASS
Largest single impurity	RP-HPLC — glutathione disulfide (GSSG, +305 Da)	0.40	% 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)	307.0843	Da	—	NOT TESTED
Mass accuracy	observed vs theoretical	+1.7	ppm	± 20	PASS
Peptide content	not ordered on this submission	not determined	—	required to check label claim	NOT TESTED
Water content	Karl Fischer, coulometric, duplicate	5.84	%	≤ 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/	0.26	%	—	NOT TESTED
Endotoxin	kinetic chromogenic LAL	5.12	EU/mg	≤ 5.0	FAIL
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	Faint haze, clearing on standing	—	clear, no visible particulates	FAIL
pH (reconstituted, 1 mg/mL)	potentiometric, two-point calibration	7.01	—	2.5 – 8.0	PASS
Retention time (observed)	RP-HPLC, 32 min gradient	4.48	min	4.54 ± 0.20 (normalised)	PASS
Peak asymmetry (10 % height)	Ph. Eur. 2.2.46	0.92	—	0.80 – 1.50	PASS
Plate count, main peak	N = 5.54 (t/w½)²	60,570	—	≥ 20,000	PASS
Resolution to nearest impurity	vs S-sulfonate adduct (+80 Da)	2.00	—	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 60,570, and skew follows the reported asymmetry factor of 0.92. 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 0.40 % impurity against a 99.25 % 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	4.48	4,823,858	99.25	—
2	glutathione disulfide (GSSG, +305 Da)	5.03	19,441	0.40	+304.984
3	cysteinyl-glycine (−129 Da)	4.22	7,776	0.16	-129.043
4	γ-Glu-Cys (−57 Da)	4.29	4,860	0.10	-57.021
5	S-sulfonate adduct (+80 Da)	4.33	4,374	0.09	+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 307.0843 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	308.0916	0.0005	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.

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	99.25	divergence +0.16 pp vs batch median
Total impurities (% area)	0.10	0.75
Largest single impurity (% area)	not stated	0.40
Water (%)	4.1	5.84
Counter-ion (%)	5.0	N/A
Peptide content (%w/w)	97.4	not determined
Endotoxin (EU/mg)	2.93	5.12
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, 2 d) → laboratory (hand-carried, 12 d) → assay.
Assay date: 29 Jul 2024
Submitted to the index: 18 Aug 2024
Laboratory: VendorInvestigate, Riga, Latvia
Method basis: 32 min gradient · high-resolution MS
Verification status: METHOD LIMITED

What this report does not establish

How much of the named compound is in the vial. Peptide content was not determined, so recovered mass cannot be calculated and the label claim cannot be checked.
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.

sig_figs18 Aug 2024

Endotoxin tested twice on this lot with varying EU/mg spread. Endotoxin variability in retained samples is larger than most labs acknowledge and the single measurement here is not definitive.

Contributor #M-368418 Aug 2024

5.12 EU/mg is elevated relative to the index median and the record shows no depyrogenation step. If this material will be reconstituted in aqueous buffer for any downstream use, that endotoxin load is a risk.

Contributor #L-440918 Aug 2024

Purity 99.25 % and endotoxin 5.12 EU/mg are unrelated — purity measures synthesis quality, endotoxin measures fill-step water quality. The combination here is coherent and expected together.

follistatin_gap18 Aug 2024

5.12 EU/mg is at the sensitivity limit of VendorInvestigate's LAL method. The true value is unspecified; treating this as a point estimate is overstating precision.

Section 7

Related records

Same batch — lot FGP-2405-E2221 n=9

Report	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Flags	Result
AX-2024-004501	FGP-2405-E2221	Janoshik	2024-Q3	99.34	5.70	—	Supplier-supplied	1	MARGINAL
AX-2024-004503	FGP-2405-E2221	Janoshik	2024-Q3	99.56	5.55	101.2	Supplier-supplied	1	MARGINAL
AX-2024-004504	FGP-2405-E2221	Janoshik	2024-Q3	99.93	5.65	—	Supplier-supplied	2	FAIL
AX-2024-004505	FGP-2405-E2221	Kestrel	2024-Q3	99.85	5.90	—	Supplier-supplied	1	MARGINAL
AX-2024-004506	FGP-2405-E2221	Janoshik	2024-Q3	99.74	6.40	—	Supplier-supplied	1	MARGINAL
AX-2024-004507	FGP-2405-E2221	Medutest	2024-Q3	99.56	5.85	—	Supplier-supplied	1	MARGINAL
AX-2024-004508	FGP-2405-E2221	Janoshik	2024-Q3	99.84	6.18	105.8	Supplier-supplied	1	MARGINAL
AX-2024-004509	FGP-2405-E2221	Janoshik	2024-Q3	99.82	6.45	101.3	Supplier-supplied	1	MARGINAL

Batch rollup and reproducibility assessment →

Cross-sections

All L-Glutathione (reduced) records n=122
All FGP records n=296
All VendorInvestigate records n=601
All 2024-Q3 records n=522
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-2026-043461	WXT	WXT-2605-B5313	PeptideMeter	2026-Q3	97.39	6.92	102.2	Supplier-supplied	0	FAIL
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

Other recent FGP records in the index.
Report	Compound	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Flags	Result
AX-2026-041742	Tirzepatide	FGP-2603-L9714	Janoshik	2026-Q3	99.37	2.43	105.5	Supplier-supplied	1	MARGINAL
AX-2026-041767	Semaglutide	FGP-2602-M1508	PeptideMeter	2026-Q3	98.65	2.54	—	Supplier-supplied	2	FAIL
AX-2026-041741	Tirzepatide	FGP-2603-L9714	PeptideMeter	2026-Q3	98.62	2.57	—	Supplier-supplied	1	MARGINAL
AX-2026-041772	Semaglutide	FGP-2602-M1508	Janoshik	2026-Q3	99.79	3.03	107.5	Supplier-supplied	0	PASS
AX-2026-041770	Semaglutide	FGP-2602-M1508	VendorInvestigate	2026-Q3	99.33	1.48	90.3	Buyer-sourced	1	MARGINAL
AX-2026-041769	Semaglutide	FGP-2602-M1508	Janoshik	2026-Q3	99.13	2.55	92.9	Supplier-supplied	1	MARGINAL
AX-2026-041768	Semaglutide	FGP-2602-M1508	Janoshik	2026-Q3	98.85	2.20	90.3	Supplier-supplied	1	MARGINAL
AX-2026-041771	Semaglutide	FGP-2602-M1508	Janoshik	2026-Q3	99.41	2.31	—	Supplier-supplied	0	PASS