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GHK-Cu vs AHK-Cu: Which Copper Peptide for Which Application
Both are copper tripeptides, both are blue, and both are sold as cosmetic actives. The difference is a single amino acid — and the application each is normally chosen for.
Formulators often arrive at the same question: I need a copper peptide, do I buy GHK-Cu or AHK-Cu? The two are frequently listed side by side, priced similarly and described in almost the same language. This page sets out what actually differs and how to decide.
What each one is
Both are copper-binding tripeptides supplied as a blue powder. The difference is the amino acid sequence, which changes the INCI name you declare on the label:
| Trade name | INCI name | Sequence | Usually chosen for |
|---|---|---|---|
| GHK-Cu | Copper Tripeptide-1 | Glycyl-Histidyl-Lysine + copper | Facial skincare — serums, creams, masks, eye products |
| AHK-Cu | Copper Tripeptide-3 | Alanyl-Histidyl-Lysine + copper | Hair and scalp products — shampoos, scalp serums, tonics |
That is the practical distinction most buyers care about, and it is why the two appear in different product categories even though they are chemically close relatives.
Why the application split exists
GHK-Cu has a long history in facial skincare, so most formulation experience, stability data and consumer familiarity sit with it. AHK-Cu is far more common in hair and scalp care, and many brands use it there specifically because it lets them make a copper-peptide claim in a category where GHK-Cu was never established.
If you are formulating a product that spans both — a serum marketed for face and scalp, for example — the usual answer is to pick one for the lead claim and keep the formula simple rather than stacking both.
Specification to require for either
Copper peptides are visually distinctive, which makes them easy to fake and easy to under-specify. Whatever you buy, the batch should come with:
| Item | What to check |
|---|---|
| HPLC purity | 98% or higher on standard cosmetic grade; look at the chromatogram, not just the number |
| MS identity | Confirms the peptide sequence — the only way to tell which tripeptide you were sent |
| Copper content | The blue colour comes from the copper complex; a colourless powder is a warning sign |
| Appearance | Deep blue to blue-violet powder; note any batch-to-batch variation |
| Batch number | Must match the number printed on the vial label |
Formulation behaviour to plan for
Both products behave similarly in a base. In practice the things that catch formulators out are the same for either:
- The colour moves. Copper peptides can shift hue in a finished base depending on pH, chelators and packaging. Test in your own base rather than in water.
- Low use levels. These are actives used at a small fraction of the formula, so the cost per gram of raw material is not the cost per unit of finished product.
- Packaging matters. Light and oxygen exposure drive colour change; an airless or opaque pack usually gives the best shelf appearance.
How to choose between them
A short decision sequence that covers most cases:
- What is the product category? Facial skincare → GHK-Cu is the default. Hair or scalp → AHK-Cu is the default.
- What claim are you making? Match the peptide to the claim; do not stretch one peptide across two very different claims.
- What can you support? Both need the same documentation. If you cannot obtain a matching COA and MS for one of them, that decides it.
- Price per gram of active — not price per kilo of powder — is the number to compare.
Buying either in bulk
Both are normally sold in 10-vial kits with strengths from 10 mg to 100 mg per vial for the cosmetic grade. Ask for the pack format you want, the COA for the specific batch, and the shelf life from the date of manufacture. The supplier selection guide covers what else to put in your first enquiry.
Comparing the two head to head
| Question | GHK-Cu | AHK-Cu |
|---|---|---|
| INCI name | Copper Tripeptide-1 | Copper Tripeptide-3 |
| Amino acid sequence | Glycyl-Histidyl-Lysine | Alanyl-Histidyl-Lysine |
| Appearance | Deep blue powder | Deep blue powder |
| Common product category | Facial skincare | Hair and scalp care |
| Typical bulk pack | 10-vial kits, 10–100 mg per vial | 10-vial kits, 10–100 mg per vial |
| Documentation to require | COA, HPLC chromatogram, MS spectrum | COA, HPLC chromatogram, MS spectrum |
The two handle closely enough that a formulator can move from one to the other without reworking the base. What changes is the claim, the label declaration, and the category a buyer expects to see them in.
What buyers get wrong when switching between them
- Forgetting the INCI change. Swapping the peptide without updating the ingredient list is a labelling error, not a formula tweak. The two have different INCI names.
- Reusing an old stability result. A trial run on GHK-Cu does not automatically qualify AHK-Cu in the same base. Re-run the short accelerated check.
- Assuming both are stocked at the same strengths. Strength ranges differ by product line. Confirm what your supplier actually holds before briefing artwork.
- Buying both to cover both claims. Two copper peptides in one product rarely strengthens a claim and does complicate the ingredient list and the stability work.
Frequently asked questions
What is the difference between GHK-Cu and AHK-Cu?
Both are copper-binding tripeptides supplied as a blue powder. GHK-Cu is Copper Tripeptide-1 (glycyl-histidyl-lysine) and is normally chosen for facial skincare; AHK-Cu is Copper Tripeptide-3 (alanyl-histidyl-lysine) and is normally chosen for hair and scalp products. The INCI name you declare differs.
Can I use GHK-Cu in a hair product instead?
There is no formulation barrier to it, but the market convention is AHK-Cu for hair and scalp. If your claim is a hair claim, using the peptide buyers expect in that category avoids having to explain the choice.
Does the blue colour indicate quality?
The blue comes from the copper complex, so a colourless product is a warning sign. But colour is not a quality measure — you still need HPLC purity and MS identity data for the specific batch.
Are they priced the same?
In the same range, yes. Price depends mainly on strength per vial, quantity and documentation rather than on which of the two you choose.
Do GHK-Cu and AHK-Cu look different?
Both are deep blue powders because the colour comes from the copper complex. You cannot tell them apart visually — only the COA, the MS identity data and the supplier's product code distinguish them.
Can I swap one for the other without telling my supplier?
No. They carry different INCI names, so a swap changes your label declaration, your PIF and potentially your registration. Treat it as a new raw material.