AX-2026-041625 · Selank · FGP lot FGP-2511-D8133

Section 1

Results

Measured against the index acceptance specification for the neuroactive and cognitive 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, 25 min gradient, 214 nm	99.76	% area	≥ 99.0	PASS
Total impurities	RP-HPLC, sum of reported peaks	0.24	% area	≤ 1.0	PASS
Largest single impurity	RP-HPLC — tuftsin fragment (−417 Da)	0.13	% area	≤ 1.00	PASS
Identity — theoretical monoisotopic mass	calculated from molecular formula	751.4402	Da	—	NOT TESTED
Identity — observed monoisotopic mass	LC-MS, unit resolution (single quadrupole)	751.4449	Da	—	NOT TESTED
Mass accuracy	observed vs theoretical	+6.2	ppm	± 15	PASS
Total peptide content	by difference from the gravimetric mass balance	85.63	%w/w	—	NOT TESTED
Target-compound content	total peptide content × purity	85.42	%w/w	—	NOT TESTED
Gross fill (as weighed)	five-place balance, under nitrogen	5.75	mg	5 mg declared	NOT TESTED
Recovered target peptide	gross fill × target content	4.912	mg	5 mg claim	NOT TESTED
Recovery against label claim	recovered ÷ claim	98.2	%	90.0 – 110.0	PASS
Water content	Karl Fischer, coulometric, duplicate	6.38	%	≤ 12.0	PASS
Counter-ion (acetate)	anion-exchange ion chromatography	7.84	%	≤ 10.0	PASS
Residual solvent + inorganic residue	estimated — see /methods/residual-solvents-q3c/	0.15	%	—	NOT TESTED
Endotoxin	kinetic chromogenic LAL	1.13	EU/mg	≤ 5.0	PASS
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	5.08	—	2.5 – 8.0	PASS
Retention time (observed)	RP-HPLC, 25 min gradient	5.46	min	5.44 ± 0.25 (normalised)	PASS
Peak asymmetry (10 % height)	Ph. Eur. 2.2.46	0.93	—	0.80 – 1.50	PASS
Plate count, main peak	N = 5.54 (t/w½)²	65,726	—	≥ 20,000	PASS
Resolution to nearest impurity	vs diketopiperazine (−18 Da)	1.72	—	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, 25 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 65,726, and skew follows the reported asymmetry factor of 0.93. 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 0.13 % impurity against a 99.76 % 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	Selank — main peak	5.46	4,848,645	99.76	—
2	tuftsin fragment (−417 Da)	4.94	6,318	0.13	-417.235
3	diketopiperazine (−18 Da)	5.61	2,916	0.06	-18.011
4	acetyl adduct (+42 Da)	5.74	2,430	0.05	+42.011
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 751.4402 Da, computed from C33H57N11O9. All ppm figures on this site are against monoisotopic values — see why that matters.

Figure 2. ESI charge-state envelope, unit-resolution instrument. Sticks are placed at m/z = (M + z × 1.007276)/z for the observed neutral mass of 751.4449 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 (%)
2+	376.7274	376.7297	0.0023	56.6
1+	752.4475	752.4522	0.0047	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	6.38
Counter-ion (acetate)	ion chromatography	7.84
Residual solvent + inorganic residue	estimated	0.15
Total peptide content	by difference	85.63
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	99.76	divergence +0.01 pp vs batch median
Total impurities (% area)	not stated	0.24
Largest single impurity (% area)	not stated	0.13
Water (%)	4.1	6.38
Counter-ion (%)	not stated	7.84
Peptide content (%w/w)	not stated	85.63
Endotoxin (EU/mg)	not stated	1.13
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, 6 d) → laboratory (courier, cold pack, 3 d) → assay.
Assay date: 27 Mar 2026
Submitted to the index: 18 Apr 2026
Laboratory: Medutest, Ljubljana, Slovenia
Method basis: 25 min gradient · unit-resolution MS
Verification status: IDENTITY CONSISTENT

What this report does not establish

That the compound is not a near-isobaric alternative. Identity was confirmed at unit mass resolution, which cannot exclude species differing by 1 or 2 Da. The specific alternatives not excluded are named in the identity block above.
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 2

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.

baseline_noise18 Apr 2026

Baseline on this trace is flat enough that the reporting threshold is doing real work rather than hiding peaks in noise. That is a precondition for believing 99.76 % and it is not always met.

fill_homogeneity18 Apr 2026

One retail vial is one draw from a fill. Two or three from the same lot would separate fill variation from lot quality, and that is the cheapest useful experiment in this whole field.

Section 7

Related records

Same batch — lot FGP-2511-D8133 n=11

Report	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Flags	Result
AX-2026-041619	FGP-2511-D8133	VendorInvestigate	2026-Q1	99.90	6.56	—	Buyer-sourced	1	FAIL
AX-2026-041620	FGP-2511-D8133	Janoshik	2026-Q1	99.93	6.91	93.8	Buyer-sourced	0	PASS
AX-2026-041621	FGP-2511-D8133	Kestrel	2026-Q1	99.89	6.35	102.3	Laboratory-retained	0	PASS
AX-2026-041622	FGP-2511-D8133	Medutest	2026-Q1	99.93	6.21	91.4	Buyer-sourced	0	PASS
AX-2026-041623	FGP-2511-D8133	Nordanalyt	2026-Q1	99.88	7.36	90.1	Buyer-sourced	0	PASS
AX-2026-041624	FGP-2511-D8133	Janoshik	2026-Q1	99.93	6.43	105.5	Buyer-sourced	0	PASS
AX-2026-041626	FGP-2511-D8133	PeptideMeter	2026-Q1	99.59	6.12	95.2	Buyer-sourced	0	PASS
AX-2026-041627	FGP-2511-D8133	Janoshik	2026-Q1	99.93	6.83	100.5	Buyer-sourced	0	PASS
AX-2026-041628	FGP-2511-D8133	PeptideMeter	2026-Q1	99.82	5.91	98.3	Buyer-sourced	0	PASS
AX-2026-041629	FGP-2511-D8133	Janoshik	2026-Q1	99.88	6.29	98.4	Laboratory-retained	1	MARGINAL

Batch rollup and reproducibility assessment →

Cross-sections

Other recent Selank records in the index.
Report	Supplier	Lot	Lab	Quarter	Purity %	Water %	Recovery %	Provenance	Flags	Result
AX-2026-042858	GGPeps	GGPE-2603-J2447	VendorInvestigate	2026-Q3	98.87	8.85	99.4	Buyer-sourced	0	FAIL
AX-2026-042859	GGPeps	GGPE-2603-J2447	PeptideMeter	2026-Q3	98.92	9.48	103.5	Buyer-sourced	0	FAIL
AX-2026-041759	TFS	TFS-{CAT}-1712	Janoshik	2026-Q2	99.93	8.13	102.2	Buyer-sourced	0	PASS
AX-2026-042912	GGPeps	GGPE-2601-J3130	Janoshik	2026-Q2	99.75	9.44	89.7	Buyer-sourced	1	MARGINAL
AX-2026-041760	TFS	TFS-{CAT}-1712	Janoshik	2026-Q2	99.82	7.70	—	Buyer-sourced	0	PASS
AX-2026-041752	TFS	TFS-{CAT}-1712	Medutest	2026-Q2	99.63	7.43	—	Buyer-sourced	1	FAIL
AX-2026-042915	GGPeps	GGPE-2601-J3130	PeptideMeter	2026-Q2	99.53	10.03	—	Buyer-sourced	0	PASS
AX-2026-042910	GGPeps	GGPE-2601-J3130	VendorInvestigate	2026-Q2	99.62	9.21	105.0	Buyer-sourced	0	PASS

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