Guide
How to read a copper-peptide COA: each line for GHK-Cu, AHK-Cu and the copper blends
Published October 9, 2026 · Facts checked October 9, 2026
Short answer
A copper-peptide COA answers four questions: is this the named peptide (MS identity), how clean is its signal (HPLC purity), how much is in the vial (assay and fill), and are contaminants within limits (endotoxin, elemental impurities). Copper is a separate measurement. On a blend, identity and assay are given for each declared peptide and purity is the sum of the declared peptides. Our batch COAs report HPLC purity, MS identity, bacterial endotoxin and fill for every batch.
Start with the header
The COA should name the product and the vial strength you ordered and carry the number of the batch it covers. We do not publish batch numbers on this site: ask sales for the COA of the batch you would receive, and compare its batch number with the one on your kit.
Line by line
| Line | What it tells you | What it does not |
|---|---|---|
| Appearance | Colour and form against the description: blue for GHK-Cu and AHK-Cu, blue to blue-green for GLOW 70 mg and KLOW 80 mg | How much copper is bound |
| Identity (MS) | The molecular ion matches the named peptide; on a blend, each declared peptide is confirmed separately | How much of it is present |
| HPLC purity | The share of the peptide-related signal; on a blend, the sum of the declared peptides | Copper, acetate or water in the powder |
| Assay | Peptide found against the label claim; on a blend, each peptide against its own claim | Identity on its own |
| Fill | The measured amount per vial against the labelled amount | Purity or copper |
| Elemental impurities | Metals such as lead or arsenic; copper is left out of this line for a copper peptide because it is part of the molecule | Copper content |
| Bacterial endotoxin | The endotoxin result for the batch | Microbial count |
Purity is not content
A high HPLC purity describes the peptide signal, not the powder. Counter-ions such as acetate and residual water add mass that HPLC purity does not see. The assay and fill lines say how much peptide is actually in the vial.
Where copper fits
None of the lines above measures copper. Copper content by ICP-OES, ICP-MS or AAS, the Cu²⁺ : peptide ratio and a UV-Vis spectrum come on request, agreed before the quote. The UV-Vis band of GHK-Cu sits near 606 nm.
Theoretical copper sets the ceiling. For a single copper peptide it is the pure 1:1 complex: 15.81 % for GHK-Cu, 15.28 % for AHK-Cu. For a blend it depends on how much GHK-Cu the vial holds: 11.29 % for GLOW 70 mg, 9.88 % for KLOW 80 mg and 11.07 % for the 50 mg GHK-Cu, TB-500 and BPC-157 blend. As-is results read lower because of acetate and water.
Sources: PubChem CID 165429100 · PubChem CID 7408502 · Bossak-Ahmad et al., Int J Mol Sci 2020 · Trapaidze et al., J Biol Inorg Chem 2012
Reading a blend COA
- Identity: one confirmation per declared peptide — three for GLOW and the 50 mg blend, four for KLOW.
- Assay by peptide: each against its own label claim, which is how you check the split, for example 50:10:10 in GLOW 70 mg.
- Purity: the sum of the declared peptides, not the purity of any one of them.
- TB-500: in our blends it is TB-500 (Thymosin Beta-4, full-length), the 43-residue peptide of about 4963.5 g/mol; MS identity confirms it like the other declared peptides.
Third-party reports next to the COA
A third-party report repeats tests at an independent laboratory. Low-resolution first pages of ours are on the batch-data page and on the product pages they belong to; sales send the full report.
Questions
- Does a GHK-Cu COA show copper content?
- Not every batch COA. HPLC purity, MS identity, endotoxin and fill are reported for each batch; copper content, the Cu²⁺ : peptide ratio and UV-Vis are available on request before the quote.
- What does purity mean on a blend COA?
- The sum of the declared peptides in the HPLC trace. How much of each peptide is in the vial is the assay, given peptide by peptide.
- Why is copper not listed with the elemental impurities?
- In a copper peptide, copper is part of the molecule, so that line leaves it out; copper content is measured on its own.
- How do I check the GLOW split on a COA?
- Read the assay of each declared peptide against its label claim: 50 mg GHK-Cu, 10 mg BPC-157 and 10 mg TB-500 in the 70 mg vial.
References
- PubChem CID 165429100 — GHK copper complex (C14H22CuN6O4, 401.91) — formula and molecular weight of the neutral 1:1 complex
- PubChem CID 7408502 — L-alanyl-L-histidyl-L-lysine (C15H26N6O4, 354.41) — AHK formula and molecular weight
- Bossak-Ahmad et al., Int J Mol Sci 2020 — ternary Cu(II) complex with GHK — d–d band of Cu(GHK) at 605–606 nm; aqua copper absorbs near 816 nm
- Trapaidze et al., J Biol Inorg Chem 2012 — Cu²⁺ binding to DAHK and GHK by ITC — 1:1 stoichiometry; conditional Kd 7.0 × 10⁻¹⁴ M at pH 7.4
- PubChem CID 16132341 — thymosin beta-4, full length (C212H350N56O78S, 4963.5) — TB-500 in our copper blends: full-length thymosin beta-4 (owner 10-03 and 10-09; pep-sku blend_tb = full-length)
Products and related guides
- GHK-Cu vials and fact table
- GLOW: GHK-Cu, BPC-157 and TB-500
- KLOW: GHK-Cu, BPC-157, TB-500 and KPV
- How to check a GHK-Cu batch