Copper-binding tripeptide
Glycyl-L-histidyl-L-lysine copper complex
GHK-Cu is a naturally occurring copper-binding complex built from a tiny three-amino-acid peptide called GHK. Researchers have been interested in it for decades because it appears to interact with processes involved in tissue remodelling, collagen and extracellular-matrix activity, cellular repair, inflammation and wound healing. The important catch? A lot of what people say about GHK-Cu comes from laboratory and animal research. Human research exists — particularly around skin and topical use — but it is much smaller than the online hype can make it seem.
GHK-Cu is a metal-peptide complex rather than simply a peptide sequence. Chemical databases can represent that complex in different charged or protonated forms. That is why apparently reputable sources may show slightly different molecular formulas or molecular weights for something all labelled GHK-Cu.
Do not confuse the molecular weight of free GHK — approximately 340.38 g/mol — with the copper complex. They are different chemical species, and quoting one for the other is a common source of confusion.
For that reason this page publishes the formula alongside the database it came from, and does not print a single molecular weight as though every record described exactly the same molecular species.
You've probably heard this one called the copper peptide. That's basically what it is — a tiny peptide, three amino acids long, that grabs onto copper and holds it.
Researchers have been poking at it for decades, because it keeps turning up in processes involved in skin, collagen and tissue repair. Genuinely interesting biology. The internet has just run a lot further with it than the research has.
Why people care
Skin and collagen get most of the attention — but that's not the only reason GHK-Cu keeps showing up in research.
This is the big one.
Most of the attention traces back to skin — whether GHK-Cu influences the signals behind collagen and the scaffolding between your cells. It's also the one area where actual human studies exist.
The oldest thread in this literature.
Wound healing is where a lot of GHK-Cu's reputation comes from. Cell and animal studies have looked at whether it nudges the processes involved in repairing tissue. Interesting work — almost all of it done outside of people.
Promising biology. Not a proven outcome.
In lab and animal models it's shown anti-inflammatory and antioxidant activity. This is the clearest example on the page of a mechanism getting mistaken for a demonstrated benefit.
Why researchers keep coming back.
GHK-Cu touches a surprisingly wide range of cellular processes. That breadth is what makes it scientifically interesting — and what makes “GHK-Cu does X” a misleading way to describe it.
Research at a glance
A 2026 systematic review searched PubMed, Embase and Cochrane CENTRAL for GHK-Cu in aesthetic medicine.
So yes — there's plenty of reason to keep studying GHK-Cu. No, that doesn't mean there's enough human evidence to treat every claim online as established fact.
See the full evidence breakdownReality check
Depends which claim we're talking about. Here's where the internet gets a little… enthusiastic.
People say“GHK-Cu boosts collagen.”
What we actually knowGHK-Cu has shown effects on collagen-related processes in cell, animal and some topical human skin research. That does not establish the same effect for every route or use.
People say“GHK-Cu reduces inflammation.”
What we actually knowAnti-inflammatory effects have been reported primarily in laboratory and preclinical models. Evidence that injected GHK-Cu reduces clinically meaningful inflammation in humans is insufficient.
People say“GHK-Cu repairs tissue.”
What we actually knowGHK-Cu has an extensive research history in tissue-remodelling and wound-healing models. Broad systemic tissue-repair claims in humans go beyond the current evidence.
People say“GHK-Cu is an anti-aging peptide.”
What we actually knowGHK-Cu is being investigated for biological processes associated with ageing and tissue remodelling. “Anti-ageing” is much broader than what clinical trials have established.
Read this part
Here's where things get a little messy. Almost all the human GHK-Cu research involves topical use — not injections.
That doesn't prove injectable GHK-Cu does nothing. It means we don't have the evidence to say it does what you'll see claimed online. Injecting changes how much gets in, where it goes and what safety questions apply — so evidence from a cream doesn't carry over.
Go deeper
Everything above is the short version.
Every study we used, what researchers actually found, where the evidence is strong, where it's weak, and what we still don't know.
Explore all GHK-Cu researchThe practical side
This page is the explanation. Protocols, calculators and preparation guides live separately, published per vial strength.
Practical guides are published per vial strength because concentration depends on both the amount in the vial and the volume added. Guidance written for one strength does not carry over to another.
Quick answers
GHK-Cu is a naturally occurring copper-binding complex built from a three-amino-acid peptide called GHK — glycine, histidine and lysine — complexed with copper.
GHK is the one-letter shorthand for its three amino acids: glycine (G), histidine (H) and lysine (K). The “Cu” is the chemical symbol for copper.
The GHK sequence binds copper, and that complex is what most of the research describes. Copper participates in a number of enzymes relevant to connective tissue, which is part of why researchers find the complex interesting.
Research has looked at extracellular-matrix and collagen-related activity, skin ageing and appearance, wound and tissue repair, inflammatory and oxidative-stress signalling, and broader cell-signalling effects. These are areas of investigation, not established outcomes.
Yes, though the human research is concentrated in topical and cosmetic contexts. A 2026 systematic review of GHK-Cu in aesthetic medicine identified 20 eligible studies, of which only two were randomised controlled human trials.
No, and treating them as interchangeable is the most common mistake made with this compound. Evidence gathered by applying something to skin says nothing about injectable effectiveness, safety or exposure. We grade the two routes separately for exactly this reason.
GHK is the peptide on its own. GHK-Cu is that peptide complexed with copper. They are different chemical species — which is also why the molecular weight of free GHK, around 340.38 g/mol, should not be quoted for the copper complex.
Research vials are commonly referenced at 50 mg and 100 mg. We publish a separate practical guide for each strength, because concentration depends on both the amount in the vial and the volume added.
The practical resources section on this page links to each strength-specific guide, or you can browse every GHK-Cu guide from the protocols directory.
Research resources
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