A GHK-Cu certificate of analysis looks like a list of numbers. It is not. It is at least four different kinds of number printed in the same table, and treating them as interchangeable is the most common mistake we see in supplier comparison. A specification is a promise. A batch result is a measurement. A theoretical value is arithmetic. A standard threshold is somebody else's requirement. They can all be correct and still disagree with one another.
This page annotates a real certificate — batch WM-T3Q9-CU, the current Copper Tripeptide-1 bulk batch, whose full COA and specification sheet are downloadable from our document centre. Every figure below is on that document. Where a number comes from somewhere else, we say so.
1. The whole certificate, annotated
Four columns matter: what the number is, how it was obtained, what kind of claim it represents, and what it does not tell you.
| Figure | What it is | Method / origin | Kind of claim |
|---|---|---|---|
| ≥98.0% | HPLC purity release limit | HPLC, stated on our specification sheet | Specification — what every batch must clear |
| 99.94% | HPLC purity, this batch | HPLC | Batch result — true of WM-T3Q9-CU only |
| ~15.8% | Theoretical elemental copper | Arithmetic: 63.55 ÷ 401.9 | Theoretical reference — salt-free complex only, not a limit |
| 8.0–16.0% | Our copper content range | Internal method, per our specification sheet | Specification |
| 14.1% | Copper content, this batch | Internal method | Batch result |
| ≥13.0% | Copper content requirement in YY/T 10005—2026 | HPLC, external standard against a copper(II) chloride dihydrate reference (Annex A) | Standard threshold — a third party's requirement |
| ≥83.0% / 93.4% | Copper Tripeptide-1 assay: standard requirement (hydrochloride tier) / this batch | Anhydrous basis, as C14H22N6O4Cu | Standard threshold / batch result |
| ≥70.0% / 79.2% | Tripeptide-1 assay: standard requirement (hydrochloride tier) / this batch | Anhydrous basis, as C14H22N6O4 | Standard threshold / batch result |
| ≤8.0% / 6.11% | Water | Karl Fischer | Specification / batch result |
| ≤10.0% / 7.27% | Chloride content | Ion chromatography | Specification / batch result — see §3 |
| 5.5–7.5 / 6.6 | pH of a 0.2% aqueous solution | — | Specification / batch result |
The same certificate also carries residual solvents (methanol, ethanol, acetonitrile, dichloromethane, ethyl acetate), bacterial endotoxin, four heavy metals and seven microbiological items. Those are pass/fail against limits rather than numbers you would compare between suppliers, so they are omitted from the table above — but their presence or absence on a competing certificate is itself informative.
2. Why 15.8% and 14.1% are both right
This is the single most frequent question we get about copper peptide documentation, and it is almost always a basis problem rather than a quality problem.
The 15.8% figure comes from dividing copper's atomic mass, about 63.55, by the molecular weight of the salt-free complex C14H22N6O4Cu, about 401.9. It describes a molecule, not a material in a drum.
Commercial GHK-Cu is usually supplied as a salt. Ours is the hydrochloride — the molecular formula on both our specification sheet and our COA is written C14H22N6O4Cu·xHCl, and the certificate reports 7.27% chloride, which is what you would expect from a hydrochloride and not from a salt-free material. Counter-ion adds mass. Mass in the denominator pushes the copper percentage down. A measured 14.1% against a theoretical 15.8% is the arithmetic working normally.
So the useful question is never “is it 15.8%?” It is: which salt form, measured by which method, reported on which basis? A supplier who cannot answer those three has not really answered the copper question. We work through the purity-versus-copper distinction in more depth in our guide to copper content versus purity percentage.
3. Two things about YY/T 10005—2026 that surprise people
China's YY/T 10005—2026 is a recommended pharmaceutical industry standard for Copper Tripeptide-1 as a cosmetic raw material, published 2026-04-03 and effective 2027-05-01. It is not a GB national standard, and it is not mandatory. What makes it useful to buyers is that it puts published numbers behind terms suppliers otherwise use loosely. Two of its definitions catch people out.
Copper content is determined chromatographically, not by an elemental method
Most buyers assume a copper figure comes from ICP-MS, ICP-OES or AAS. Annex A of the standard specifies otherwise: the sample is extracted, separated by HPLC and detected at 220 nm; a copper(II) chloride dihydrate reference standard is used; the copper ion peak is integrated and the content calculated by external standard peak area, corrected to an anhydrous basis. Tripeptide-1 is quantified in the same run.
This matters commercially. A copper figure produced by an elemental method and a copper figure produced by the Annex A chromatographic method are answering slightly different questions. Before comparing any supplier's copper number against the standard's ≥13.0%, confirm which method produced it. That includes ours: our specification sheet states an internal method for copper content, and we do not assert that it is interchangeable with Annex A. Ask, and ask the other supplier too.
“Copper Tripeptide-1 content” is a sum, and “purity” includes the copper peak
Annex A defines the Copper Tripeptide-1 content as the arithmetic sum of the copper content and the Tripeptide-1 content. It is not an independent measurement. On our batch that reads 14.1% + 79.2% = 93.3%, and the certificate reports 93.4% — the difference is rounding of the underlying values.
Separately, the standard computes purity by area normalisation as the sum of the copper ion peak and the Tripeptide-1 peak area percentages. That is not the same thing as “peptide peak purity”, which is what most buyers picture when they read a purity number. Two certificates can both say 99% and mean different things.
4. Everything is on an anhydrous basis — which is why water content is not a footnote
The Annex A content formulas divide by (1 − water content). Every assay figure in the standard is therefore reported as if the material were dry. A batch carrying 6.11% water and a batch carrying 2% water will report assay values that are already normalised for that difference, but the material you weigh into a formulation is the wet material.
Practical consequence: if you are dosing to a target active level, the assay percentage and the water content have to be read together. A certificate that reports assay without reporting water has given you half of a calculation.
5. Where our batch sits against the standard
We are not claiming conformity — a conformity claim requires an item-by-item method comparison we have not completed, and we would rather say that plainly than imply otherwise. What we can do is put the two sets of numbers side by side and let you read them.
| Item | YY/T 10005—2026 requires (hydrochloride tier) | Our COA for WM-T3Q9-CU reports |
|---|---|---|
| Purity | ≥98.0% | 99.94% |
| Copper content (anhydrous) | ≥13.0% | 14.1% (internal method — see §3) |
| Copper Tripeptide-1 content (anhydrous) | ≥83.0% | 93.4% |
| Tripeptide-1 content (anhydrous) | ≥70.0% | 79.2% |
| Water | ≤8.0% | 6.11% |
| pH (2 mg/mL) | 5.0–7.5 | 6.6 (0.2% aqueous = 2 mg/mL) |
Note the tiering: the standard sets different content limits for salt-free, hydrochloride and acetate material — ≥91.0%, ≥83.0% and ≥78.0% respectively for Copper Tripeptide-1 content. Thirteen percentage points separate the top and bottom tiers. A content figure quoted without its salt form is not comparable to anything. Our fuller read-out of both new standards is here: what YY/T 10005 and 10004 actually specify.
6. What to do with two competing certificates
Put them side by side and answer these before you compare a single number:
- Salt form. Salt-free, hydrochloride, acetate? Check the molecular formula line, and cross-check it against chloride or acetate content if reported.
- Basis. As-is or anhydrous? If the certificate does not say, it is not comparable to a standard that specifies anhydrous.
- Method per line. Especially copper. Chromatographic and elemental figures should not be compared without confirming equivalence.
- Specification versus result. Two columns, two meanings. A supplier quoting only a result has not told you what they commit to on the next batch.
- Batch identity. Does the certificate name the batch you are actually being offered, or is it a reference document from an older lot?
- Scope of testing. Residual solvents, endotoxin, heavy metals and microbiology are either present or they are not. Their absence is not a failure — it is a gap in what the document can support.
If a quotation is materially cheaper, the productive question is not why the other supplier is expensive. It is what does that certificate measure, on what basis, and for which lot — the same reasoning we set out in why GHK-Cu quotations differ.
Frequently Asked Questions
Why does the COA say 14.1% copper when GHK-Cu is supposed to be 15.8%?
15.8% is the theoretical elemental copper content of the salt-free complex C14H22N6O4Cu (63.55 ÷ 401.9). Material supplied as a hydrochloride or acetate salt carries additional counter-ion mass, so the measured copper percentage is lower. A hydrochloride batch reporting 14.1% is behaving normally, not underperforming.
Is copper content measured by ICP?
Not under YY/T 10005—2026. Annex A of that standard determines copper by HPLC at 220 nm using a copper(II) chloride dihydrate reference standard and an external standard peak-area calculation on an anhydrous basis. Other suppliers may use elemental methods such as ICP-MS or AAS. Confirm the method before comparing two copper figures, or before comparing either against the standard's threshold.
What is the difference between copper content and Copper Tripeptide-1 content?
They are different measurands. Under Annex A of YY/T 10005—2026, Copper Tripeptide-1 content is defined as the arithmetic sum of the copper content and the Tripeptide-1 content, all on an anhydrous basis. On our current batch that is 14.1% + 79.2%, reported as 93.4%.
Does a purity figure on a GHK-Cu COA mean peptide peak purity?
Not necessarily. YY/T 10005—2026 computes purity by area normalisation as the sum of the copper ion peak and the Tripeptide-1 peak area percentages. A supplier using a different convention may report a purity number that is not directly comparable. Ask which peaks are included.
Why does the salt form change the acceptance limits?
Because counter-ion mass dilutes the active. YY/T 10005—2026 sets Copper Tripeptide-1 content limits of ≥91.0% for salt-free, ≥83.0% for hydrochloride and ≥78.0% for acetate material. A content figure quoted without a salt form cannot be checked against any of them.
Does WUMO's Copper Tripeptide-1 comply with YY/T 10005—2026?
We do not make a conformity claim. The standard takes effect on 2027-05-01, and a conformity statement would require a completed item-by-item method comparison, including confirmation that our internal copper method is equivalent to the Annex A procedure. What we publish instead is the standard's requirement alongside what our current batch certificate actually reports, so buyers can read both. See §5 above.
Which batch does the annotated certificate describe?
Batch WM-T3Q9-CU, the current Copper Tripeptide-1 bulk batch, manufactured 2026-06-19. The full certificate and the product specification sheet can be downloaded from our document centre. Batch-specific documents for the lot you are quoted are provided on request — you can raise one through the RFQ and documentation request form.