AssayIndex
Short bioregulator peptides

Epitalon

epithalon · Ala-Glu-Asp-Gly · AEDG · C14H22N4O9 · monoisotopic 390.1387 Da. The index holds 37 assay reports on this compound across 11 batches from 8 suppliers.

37 reports11 batchesmedian 98.63 %index spec 99.0 %
Section 1

Analytical fingerprint

Hand-authored chemistry. These properties describe the substance and do not change when a record is added.

Epitalon's Asp-Gly bond is the textbook aspartimide site, and the resulting β-Asp isomer is mass-identical and elutes 0.10 min early. On the sub-5-minute retention this compound has, that is not a separation. Epitalon purity figures above 99 % should therefore be read as "no resolvable impurity detected under these conditions" rather than as evidence of isomeric purity, and the index states that on every epitalon record. A dedicated ion-pair method is required to see the isomer, and one index lab offers it.

Molecular formula
C14H22N4O9
Monoisotopic mass
390.1387Da
Average mass
390.35Da
Residues
4
Nominal retention (RG-2, 30 min)
4.62min
Retention window
0.20min
Counter-ion as usually shipped
acetate
Typical label claims
10 mg · 20 mg · 50 mg
Analytical difficulty (index scale)
0.80 — straightforward
Purity is a defined quantity
YES
Section 2

Representative chromatogram

Drawn from this page's own medians. Not a scan, not an illustration, and not any single report.

05765115301729523060 Epitalon4.62 min · 98.63 % 4.42 same trace · ×200 vertical expansion, baseline-corrected · main peak off-scale reporting threshold 0.05 % area 05101520253035 Retention time (min) Response (mAU)
Figure 1. A representative Epitalon trace on the index reference method RG-2, constructed from this page's own numbers: the main peak carries the index median purity of 98.63 % area at the nominal retention time of 4.62 min, and each impurity peak carries the median area the index has observed for that named species at its characteristic retention offset. It is not a scan of any single report — every individual record's own chromatogram is on its own page. The lower panel is the same trace at a stated vertical expansion, baseline-corrected, so the impurities are visible; the main peak runs off-scale there by design. Baseline noise is seeded from the compound slug.
Section 3

What the index has observed

Arithmetic over the 37 records the index holds. Aggregates on this page are computed over the records the index holds, which are not a random sample of the material on the market. Lots that get tested are lots someone chose to test. Read every figure here as a description of this dataset rather than as an estimate of a population.

Median purity 98.63% n=37
Interquartile range 1.02pp n=37
Minimum 97.28% n=37
Maximum 99.93% n=37
Pass rate vs spec 37.8% n=37
Median recovery vs claim 94.3% n=22
Median water 6.99% n=37
Median |mass error| 2.2ppm n=29
024692.093.094.095.096.097.098.099.0100.092.00–92.25 %: n=092.25–92.50 %: n=092.50–92.75 %: n=092.75–93.00 %: n=093.00–93.25 %: n=093.25–93.50 %: n=093.50–93.75 %: n=093.75–94.00 %: n=094.00–94.25 %: n=094.25–94.50 %: n=094.50–94.75 %: n=094.75–95.00 %: n=095.00–95.25 %: n=095.25–95.50 %: n=095.50–95.75 %: n=095.75–96.00 %: n=096.00–96.25 %: n=096.25–96.50 %: n=096.50–96.75 %: n=096.75–97.00 %: n=097.00–97.25 %: n=097.25–97.50 %: n=197.50–97.75 %: n=497.75–98.00 %: n=098.00–98.25 %: n=598.25–98.50 %: n=698.50–98.75 %: n=598.75–99.00 %: n=299.00–99.25 %: n=599.25–99.50 %: n=199.50–99.75 %: n=399.75–100.00 %: n=5median 98.63 Purity (% area) Reports
Figure 2. Purity distribution across all 37 Epitalon records. Dashed line is this compound's median (98.63 %); the solid vertical is the index acceptance specification for the short bioregulator peptides class (99.0 %). Domain is fixed at 92–100 % on every purity histogram on this site so that compounds can be compared by eye — a wide distribution here is a hard compound, a narrow one is an easy one, and neither is a statement about the suppliers.
Section 4

By supplier

Suppliers with fewer than two purity records on this compound are omitted from the figure rather than drawn as a line. The full table, including the thin cells, is on the by-supplier page.

97.197.698.198.699.199.6100.1KPKP: Q1 97.71, median 98.22, Q3 98.33, n=17n=17TFCTFC: Q1 98.53, median 98.85, Q3 99.14, n=11n=11HomopeptideHomopeptide: Q1 99.50, median 99.65, Q3 99.79, n=2n=2JEEPJEEP: Q1 99.93, median 99.93, Q3 99.93, n=2n=2QSCQSC: Q1 99.76, median 99.81, Q3 99.87, n=2n=2 Purity (% area)
Figure 3. Epitalon purity by supplier, ordered by coverage. The vertical line is the index acceptance specification. Boxes that overlap are suppliers this dataset cannot separate, and most of them overlap.

Full per-supplier table with n= caveats →

Section 5

Characteristic impurities and degradants

The left three columns are authored chemistry — what this molecule characteristically carries and where it elutes. The right three are what the index has actually reported.

Named speciesΔRT (min, RG-2)Δ mass (Da)Seen inMedian % areaMax % area
aspartimide (−18 Da)+0.12-18.01197%0.191.66
Ala-Glu-Asp tripeptide (−57 Da)-0.20-57.02195%0.271.76
diketopiperazine (−18 Da)+0.16-18.01195%0.140.99
β-Asp isomer-0.10mass-identical92%0.251.35

Degradation pathways

  • Asp-Gly aspartimide, then hydrolysis to the β-Asp isomer — the classic tetrapeptide problem

Full impurity profile, with what each named species implies about the synthesis →

Section 7

Quarterly coverage

QuarterReportsMedian purityRange
2024-Q10n<3—
2024-Q20n<3—
2024-Q32n<399.70–99.93
2024-Q40n<3—
2025-Q11n<3—
2025-Q22n<399.93–99.93
2025-Q30n<3—
2025-Q42n<398.77–99.56
2026-Q11998.4497.28–99.24
2026-Q21198.3997.61–99.93
2026-Q30n<3—

Quarter-by-quarter detail →

Section 8

Most recent records

The 25 most recent Epitalon records of 37.
ReportSupplierLotLabQuarterPurity %Water %Recovery %ProvenanceFlagsResult
AX-2026-043099KPKP-2512-R5829PeptideMeter2026-Q298.336.5294.5Supplier-supplied2FAIL
AX-2026-042209HomopeptideHOMO-2512-A1223Janoshik2026-Q299.937.83100.3Supplier-supplied0FAIL
AX-2026-042208HomopeptideHOMO-2512-A1223PeptideMeter2026-Q299.367.93102.7Supplier-supplied0FAIL
AX-2026-043098KPKP-2512-R5829Janoshik2026-Q297.716.99—Supplier-supplied2FAIL
AX-2026-041270WWBWWB-2602-G2822Janoshik2026-Q299.756.6988.9Supplier-supplied1MARGINAL
AX-2026-043097KPKP-2512-R5829Janoshik2026-Q298.006.7491.6Supplier-supplied2FAIL
AX-2026-043096KPKP-2512-R5829Medutest2026-Q297.616.3897.0Buyer-sourced3FAIL
AX-2026-043095KPKP-2512-R5829Janoshik2026-Q297.686.82—Supplier-supplied2FAIL
AX-2026-043094KPKP-2512-R5829Medutest2026-Q299.066.8990.5Supplier-supplied3MARGINAL
AX-2026-043092KPKP-2512-R5829Janoshik2026-Q298.636.87—Supplier-supplied2FAIL
AX-2026-043093KPKP-2512-R5829Medutest2026-Q298.396.17107.0Supplier-supplied2FAIL
AX-2026-043070KPKP-2508-Y5329PeptideMeter2026-Q198.338.14—Supplier-supplied1FAIL
AX-2026-042009TFCTFC-2508-W5644Janoshik2026-Q198.427.29—Supplier-supplied0FAIL
AX-2026-042010TFCTFC-2508-W5644Janoshik2026-Q198.656.9590.2Supplier-supplied0FAIL
AX-2026-043071KPKP-2508-Y5329Medutest2026-Q198.258.6492.3Supplier-supplied0FAIL
AX-2026-042005TFCTFC-2508-W5644Medutest2026-Q199.217.10—Supplier-supplied1MARGINAL
AX-2026-042004TFCTFC-2508-W5644Medutest2026-Q199.246.7590.6Supplier-supplied0FAIL
AX-2026-042011TFCTFC-2508-W5644Medutest2026-Q199.006.4499.6Supplier-supplied0FAIL
AX-2026-043068KPKP-2508-Y5329VendorInvestigate2026-Q197.287.8191.9Buyer-sourced0FAIL
AX-2026-042003TFCTFC-2508-W5644Janoshik2026-Q198.506.39—Buyer-sourced0FAIL
AX-2026-043069KPKP-2508-Y5329VendorInvestigate2026-Q197.707.91—Buyer-sourced0FAIL
AX-2026-043063KPKP-2508-Y5329Medutest2026-Q198.228.15—Buyer-sourced1FAIL
AX-2026-042008TFCTFC-2508-W5644Janoshik2026-Q199.076.7689.9Supplier-supplied1MARGINAL
AX-2026-043066KPKP-2508-Y5329Medutest2026-Q198.688.10—Supplier-supplied0FAIL
AX-2026-043067KPKP-2508-Y5329VendorInvestigate2026-Q198.227.97100.7Buyer-sourced0FAIL