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The molecule

GHK-Cu

A copper tripeptide your body already makes

GHK-Cu is a small piece of protein bound to a copper ion. The GHK part is a tripeptide — three amino acids joined in a chain — with copper sitting alongside it.

It was first noticed in human blood plasma, and levels tend to fall as we get older. That drop is part of why it has been studied as a topical ingredient for older or stressed skin.

G: GlycineThe first of three amino acids in the chain
H: HistidineThe second amino acid
K: LysineThe third amino acid
Cu: CopperThe ion bound alongside the tripeptide

When you see "copper peptide" on a skincare label, GHK-Cu is usually the one being referred to.

The evidence

What the research actually says

The clearest single source is a review by Pickart and Margolina, published in the International Journal of Molecular Sciences in 2018. It gathers decades of laboratory and small clinical work on GHK-Cu, describing the peptide as playing a role in skin remodeling and in the signals cells use during repair.

A review is a summary of other studies, not a single large trial. Much of the underlying work was done in cell cultures or in small groups of people.

Copper peptides are one of the more researched ingredients in this category. That does not make every marketing claim about them true.

So the honest framing is this: GHK-Cu has been studied for support of skin repair and the appearance of firmness, and the results look promising — but the strongest claims still need larger human trials. We say may help, not proven to cure.

How it works in skin
GHK-Cu is thought to interact with the systems your skin uses to rebuild its structure over time, including collagen. It has also been looked at around inflammation. The key word is thought — these are active areas of study, not settled facts.
If your skin is reactive
Copper peptides are generally considered well tolerated. Still, no active is right for everyone. If your skin flares easily, go carefully and patch test before adding any new treatment.
The copper purge, said plainly
Some people see a short adjustment period, where skin looks briefly more reactive for a week or two. This is not universal and it is not a rule. Strong or worsening irritation is not a purge — it is a reason to stop.

What does GHK-Cu stand for?

GHK-Cu is a copper tripeptide. GHK names the three amino acids in the peptide — glycine, histidine, lysine — and Cu is the chemical symbol for copper, which is bound to it.

Is GHK-Cu backed by research?

It is one of the more studied peptides in skincare. A 2018 review by Pickart and Margolina in the International Journal of Molecular Sciences summarises the work. Much of that work is early stage, so we describe it as promising rather than settled.

Which PepChoice product contains GHK-Cu?

The Recovery Lotion is the product with GHK-Cu. It is our leave-on treatment step. The Beauty Bar does not contain it.

What is a copper purge?

A copper purge is a short adjustment period some people see when starting a copper peptide, where skin looks briefly more reactive. It is not guaranteed, and strong or worsening irritation is a reason to stop rather than push through.

Can I use GHK-Cu on sensitive skin?

Copper peptides are usually well tolerated, but reactive skin should go slowly. Patch test, introduce it a few times a week at first, and stop if it does not settle.

Does GHK-Cu build collagen?

GHK-Cu has been studied for its role in the systems skin uses to rebuild structure, including collagen. The lab work is encouraging, but we avoid promising a fixed result on any one person's skin.

Sources

Pickart L, Margolina A. Regenerative and Protective Actions of the GHK-Cu Peptide. International Journal of Molecular Sciences, 2018.

For external use on intact skin only. Not intended to diagnose, treat, cure or prevent any disease. Patch test before first use, and consult a professional if you are pregnant, nursing or taking medication.