AssayIndex
Tissue-repair and immunomodulatory peptides

GHK-Cu

copper tripeptide-1 · Gly-His-Lys copper(II) · C14H22CuN6O4 · monoisotopic 401.1024 Da. The index holds 41 assay reports on this compound across 10 batches from 9 suppliers.

41 reports10 batchesmedian 98.54 %index spec 97.0 %
Section 1

Analytical fingerprint

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

GHK-Cu is the one compound in the index where the standard RP-HPLC method is actively wrong. A 0.1 % TFA mobile phase dissociates the copper complex on-column, so the chromatogram of authentic GHK-Cu looks like a chromatogram of apo-GHK with a copper-shaped hole in it. Reports must therefore state whether purity refers to the complex or to the peptide, and the index normalises everything to the peptide with copper determined separately by ICP-MS or by a colourimetric assay. Any GHK-Cu report without a copper number is recorded as partial. This is the single largest source of method-mismatch corrections on file.

Molecular formula
C14H22CuN6O4
Monoisotopic mass
401.1024Da
Average mass
401.91Da
Residues
3
Nominal retention (RG-2, 30 min)
6.18min
Retention window
0.25min
Counter-ion as usually shipped
none expected
Typical label claims
50 mg · 100 mg · 200 mg
Analytical difficulty (index scale)
1.20 — moderate
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.

0430686121291717223 GHK-Cu6.18 min · 98.54 % 6.80 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 GHK-Cu trace on the index reference method RG-2, constructed from this page's own numbers: the main peak carries the index median purity of 98.54 % area at the nominal retention time of 6.18 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 41 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 98.54% n=41
Interquartile range 0.69pp n=41
Minimum 96.68% n=41
Maximum 99.93% n=41
Pass rate vs spec 95.1% n=41
Median recovery vs claim 104.1% n=16
Median water 4.60% n=41
Median |mass error| 1.3ppm n=35
03692.093.094.095.096.097.098.099.0100.092.00–92.25 %: 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=196.75–97.00 %: n=197.00–97.25 %: n=097.25–97.50 %: n=297.50–97.75 %: n=297.75–98.00 %: n=298.00–98.25 %: n=298.25–98.50 %: n=898.50–98.75 %: n=698.75–99.00 %: n=699.00–99.25 %: n=399.25–99.50 %: n=599.50–99.75 %: n=199.75–100.00 %: n=2median 98.54 Purity (% area) Reports
Figure 2. Purity distribution across all 41 GHK-Cu records. Dashed line is this compound's median (98.54 %); the solid vertical is the index acceptance specification for the tissue-repair and immunomodulatory peptides class (97.0 %). 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.

96.497.097.798.398.999.6100.2ERPERP: Q1 98.38, median 98.49, Q3 98.84, n=12n=12WWBWWB: Q1 99.15, median 99.42, Q3 99.50, n=7n=7HomopeptideHomopeptide: Q1 98.95, median 99.00, Q3 99.04, n=6outlier 98.35outlier 99.42n=6KPKP: Q1 98.46, median 98.68, Q3 98.71, n=5outlier 97.89n=5GL BiochemGL Biochem: Q1 96.80, median 97.27, Q3 97.36, n=5n=5SSASSA: Q1 98.06, median 98.16, Q3 98.25, n=2n=2CPCCPC: Q1 98.42, median 98.46, Q3 98.50, n=2n=2 Purity (% area)
Figure 3. GHK-Cu 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
apo-GHK (copper-free, −62 Da)-0.48-61.930100%0.190.94
GHK-Cu 2:1 complex+0.62+277.145100%0.371.12
Gly-His dipeptide (−128 Da)-0.70-128.09595%0.201.74
oxidised His (+16 Da)-0.24+15.99595%0.321.46

Degradation pathways

  • copper dissociation at acidic pH — the mobile phase itself strips it
  • His oxidation catalysed by the bound copper

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-Q3699.0098.35–99.42
2024-Q40n<3—
2025-Q10n<3—
2025-Q20n<3—
2025-Q31197.8996.68–99.93
2025-Q40n<3—
2026-Q10n<3—
2026-Q22498.5397.53–99.93
2026-Q30n<3—

Quarter-by-quarter detail →

Section 8

Most recent records

The 25 most recent GHK-Cu records of 41.
ReportSupplierLotLabQuarterPurity %Water %Recovery %ProvenanceFlagsResult
AX-2026-043144SSASSA-2604-V7620Janoshik2026-Q298.355.25105.8Supplier-supplied0PASS
AX-2026-042550ERPERP-2601-F7633Janoshik2026-Q298.534.43—Supplier-supplied1MARGINAL
AX-2026-042571ERPERP-2604-K8139Medutest2026-Q299.256.66104.4Supplier-supplied1MARGINAL
AX-2026-042552ERPERP-2601-F7633Kestrel2026-Q298.394.13—Supplier-supplied0PASS
AX-2026-041251WWBWWB-2512-B1996PeptideMeter2026-Q299.566.16—Supplier-supplied0PASS
AX-2026-041247WWBWWB-2512-B1996PeptideMeter2026-Q299.935.95104.8Supplier-supplied0PASS
AX-2026-043205SGNSGN-2603-X9044Janoshik2026-Q297.534.6898.0Supplier-supplied0PASS
AX-2026-041250WWBWWB-2512-B1996Janoshik2026-Q299.436.14—Supplier-supplied0PASS
AX-2026-042551ERPERP-2601-F7633Nordanalyt2026-Q298.414.50—Laboratory-retained0PASS
AX-2026-041246WWBWWB-2512-B1996Janoshik2026-Q298.855.7189.8Supplier-supplied1MARGINAL
AX-2026-043267CPCCPC-2601-D2294Janoshik2026-Q298.397.18—Supplier-supplied1MARGINAL
AX-2026-042556ERPERP-2601-F7633PeptideMeter2026-Q298.844.48—Supplier-supplied0PASS
AX-2026-042570ERPERP-2604-K8139Janoshik2026-Q298.026.4396.6Supplier-supplied1MARGINAL
AX-2026-041248WWBWWB-2512-B1996PeptideMeter2026-Q299.046.05—Supplier-supplied0PASS
AX-2026-042554ERPERP-2601-F7633Janoshik2026-Q298.454.56—Supplier-supplied0PASS
AX-2026-043143SSASSA-2604-V7620PeptideMeter2026-Q297.964.60102.7Buyer-sourced0PASS
AX-2026-042555ERPERP-2601-F7633Medutest2026-Q298.873.93—Supplier-supplied0PASS
AX-2026-043266CPCCPC-2601-D2294Janoshik2026-Q298.536.40—Supplier-supplied1MARGINAL
AX-2026-041249WWBWWB-2512-B1996Medutest2026-Q299.425.93—Laboratory-retained0PASS
AX-2026-041245WWBWWB-2512-B1996PeptideMeter2026-Q299.266.33106.9Supplier-supplied0PASS
AX-2026-042557ERPERP-2601-F7633Kestrel2026-Q298.864.4395.4Supplier-supplied0PASS
AX-2026-042553ERPERP-2601-F7633Janoshik2026-Q298.544.20—Supplier-supplied0PASS
AX-2026-042558ERPERP-2601-F7633PeptideMeter2026-Q298.234.09104.0Supplier-supplied0PASS
AX-2026-042569ERPERP-2604-K8139Medutest2026-Q298.346.96—Supplier-supplied1MARGINAL
AX-2025-020515KPKP-2502-C5740VendorInvestigate2025-Q397.894.12—Buyer-sourced0PASS