GHK-Cu
Glycyl-L-Histidyl-L-Lysine Copper Complex
Also called copper peptide, GHK, glycyl-L-histidyl-L-lysine, copper tripeptide-1, GHK Cu
A copper-carrying fragment of collagen, studied mostly on skin
GHK-Cu is a small peptide that carries a copper atom, found naturally in human blood. It has been studied for skin, wound healing and hair. Every human study of it on skin used a cream or gel; no published human trial has injected it. The one independent randomised facial trial found no objective change.
A naturally occurring copper-binding tripeptide, studied mainly for wound healing and skin. It carries copper into tissue, where copper is the cofactor the enzyme that cross-links collagen cannot work without. Most of the evidence is topical or preclinical; the widely quoted gene-expression claims rest on far less than they appear to.
- Route studied
- Topical (human studies)
- Status
- Sold as a cosmetic ingredient; injectable forms are not approved drugs
Studied in people, and well studied in preclinical models
152 papers · 1 clinical trial
What GHK-Cu has been studied for
The reasons people look it up, roughly in order of how often, and what research exists for each. Interest in a use is not evidence that it works; the evidence is stated under each one.
- Wound healing
- Its strongest evidence. A randomised, placebo-controlled trial of a topical gel in diabetic foot ulcers reported better closure and fewer infections.
- Skin and collagen
- The most common reason people look it up, though the one well-designed independent facial trial found no objective change.
- Hair
- Widely marketed for this, with far less published behind it than the skin claims.
- Delivering copper
- Copper is required by the enzyme that cross-links collagen and elastin, which is the clearest mechanism here.
Mechanism of Action
How GHK-Cu works
Here is the part most pages skip: GHK-Cu is a piece of collagen. Three amino acids, taken from the middle of the collagen molecule your skin is built out of.
That matters because of when it appears. Intact collagen does not release it. Damaged collagen does. So when skin is cut, burned or worn down, the breakage itself frees this fragment into the wound. It is not a foreign compound that happens to help skin. It is the signal skin already uses to say something broke here.
Why it drags a copper atom around
Your body welds collagen fibres to each other. Loose collagen strands are floppy; welded ones give skin its snap. The tool that does the welding is an enzyme, and that enzyme is useless without copper.
But copper cannot simply float around loose. Free copper is genuinely destructive: it drives the kind of reactions that damage the tissue you are trying to repair. So it travels held. GHK grips a single copper atom, partly with the ring in its middle amino acid, and carries it. That grip is also why solutions of it are blue. The colour is the copper, held.
So the compound is a delivery van. It shows up exactly where collagen has broken, carrying the one ingredient the repair crew cannot work without.
The preclinical finding worth knowing
In a preclinical wound model it did something more interesting than "more collagen". It raised a protein called decorin and lowered one called biglycan.
Decorin's job is arranging collagen into neat parallel bundles. That arrangement is roughly the difference between a scar and normal skin: a scar is not short of collagen, it is collagen laid down in a mess. So the claim is not that you get more of the stuff, but that you get it stacked properly. The catch is that the researchers injected it straight into the wound.
The claim you should discount
You will read that GHK-Cu "resets 4,000 genes". That number comes from re-analysing a public database rather than running an experiment: three microarray profiles, from prostate and breast cancer cell lines, with a crude cut-off and no statistical test. No skin cells were involved anywhere in it. The authors' own conclusion was that there was not yet enough information to say what any of it does biologically.
It is a real number attached to a very small thing. The copper delivery story is far more modest and far better supported.
GHK-Cu side effects: what studies reported
Reported effects differ by route. On skin they are mild and local. All the human evidence is topical; no published human trial has injected it.
Reported with topical use
- Redness, stinging or itching where applied, usually settling as skin adjusts
- Dryness or flaking early on
- A faint blue-green tint from the copper, which washes off
Worth keeping an eye on
- The copper uglies: some people report skin looking briefly worse, more textured or slack, in the first weeks. Skin that keeps getting worse is a reason to see a dermatologist
- Irritation when combined with retinoids or acids
- Injection-site reactions and a metallic taste, reported outside any trial by people injecting it
Reasons to check first
- Wilson's disease or any condition affecting how your body handles copper
- Use on broken or freshly needled skin raises a sterility concern, not a skincare one
Source: Cosmetic trial data plus widely reported use. This is a summary of published findings, not a complete safety profile and not medical advice. Questions about GHK-Cu belong with a licensed clinician who knows your history.
Your Genetics & GHK-Cu
The genes involved in how GHK-Cu works
GHK-Cu works through the receptors these genes build, and the genes vary from person to person. Researchers have linked some of that variation to differences in how people respond. A DNA report tells you which versions you carry.
SOD2 · ••
The Ala16Val variant has been associated with differences in how the SOD2 antioxidant enzyme reaches mitochondria. Cell studies report GHK-Cu raising SOD expression. No study has tested whether SOD2 genotype changes response to GHK-Cu.
COL1A1 · ••
The Sp1 binding site variant has been associated with differences in type I collagen production and with bone and connective tissue traits. That is a statement about collagen, not about response to GHK-Cu.
TGFB1 · ••
Associated with differences in TGF-beta1 levels, a signal involved in wound healing, scarring and tissue remodelling. GHK-Cu acts on TGF-beta pathways in cell studies; any link between this variant and GHK-Cu is untested.
SIRT1 builds an enzyme involved in DNA repair and cellular stress responses, and variants have been studied for their association with metabolic traits. A link to GHK-Cu is a hypothesis drawn from gene-expression data, not a finding.
The dots after each gene are where your own result goes. Your report fills them in with the two letters you carry at that position.
Which of these variants do you carry?
Your report reads the DNA file you already have against this research.
Often discussed alongside
Compounds that come up next to GHK-Cu in research and discussion. Each has its own page. None of this is a suggestion to combine them.
BPC-157
tissue repair researchModerate EvidenceBody Protection Compound 157
BPC-157 comes up whenever people talk about injuries that will not heal: tendons, ligaments, a gut irritated by painkillers. It is a short chain of amino acids copied from part of a protein the stomach already makes, and the preclinical research on it is unusually consistent for this category: across many separate preclinical studies, injured tissue healed faster than it did without it. The gap is that this has largely not been repeated in people, and it is not an approved medicine, so no regulator checks the quality of what is sold under its name.
3
Gene variants
19+
Studies
TB-500
tissue repair researchEmerging EvidenceTB-500
TB-500 is a short seven-amino-acid fragment copied from the middle of a much larger protein your body makes called thymosin beta-4. That protein is 43 amino acids long and helps cells travel to the site of an injury; TB-500 is the small piece of it thought to do that job. The human trials used the full protein, not the fragment, and the name TB-500 is applied to both, which makes much of what is written about it ambiguous.
3
Gene variants
50+
Studies
Access
Access and legal status
GHK-Cu: Sold as a cosmetic ingredient; injectable forms are not approved drugs. Decisions about any prescription medicine belong to a prescriber. We don't link to any seller, and nothing on this page is a recommendation to obtain or use it.
Your DNA and GHK-Cu: see which of the variants studied alongside it you carry, and what that research does and does not show. Read my DNA, $99 →
Educational information only, not medical advice. Most peptides are not FDA-approved. Do not start, stop or change any medication or peptide because of this page; talk to a licensed clinician.
Worth knowing about GHK-Cu
Interactions and situations where there is a specific reason to be careful. Where the honest answer is that nobody has studied something, it says so and says what that leaves open.
- Injected copper bypasses the gut's control
- GHK-Cu is about 15.8% copper by weight. Daily copper limits are written for food, where the gut decides how much to absorb and refuses the rest. Injection skips that control, no limit has been set for copper given that way, and no human trial has injected GHK-Cu.
- Wilson's disease or any copper-handling disorder
- The same reasoning, sharpened. In anyone whose body already struggles to clear copper, a copper-carrying peptide adds to the problem, and its safety in that situation has never been studied.
- Vitamin C at the same time
- Ascorbic acid reduces copper and can break the complex apart, so the two can inactivate each other in contact. This one is straightforward chemistry rather than speculation.
The evidence behind GHK-Cu
Read the counts below carefully, because they are the whole story. In fifty years there has been exactly one randomised controlled trial of GHK-Cu on facial skin, and it found no objective benefit. The positive human result is for a topical gel on diabetic foot ulcers, which is a different problem from cosmetic ageing. No published human trial has ever injected GHK-Cu. It is also worth knowing that most of the foundational literature comes from one researcher who founded two companies selling GHK-Cu products.
The literature, counted
Counted in PubMed on 3 August 2026 for GHK-Cu OR glycyl-L-histidyl-L-lysine. Every figure links to the search that produced it, so you can re-run it. “Tagged human” is not the same as a human trial: that tag also covers work on human cells and reviews discussing people, which is why the trial count is given separately.
Studied in people
2 of 2The only kind that directly answers whether it works in humans.Archives of Facial Plastic Surgery · 2006
HumanEffects of topical copper tripeptide complex on CO2 laser-resurfaced skin
Miller TR, Wagner JD, Baack BR, et al.
The only randomised controlled trial of GHK-Cu on facial skin, and it was negative. No significant difference in redness, wrinkles or skin quality by computer analysis or blinded assessors. Only the patients' own questionnaire favoured it. It is run by authors with no product interest, and it is absent from essentially every page selling copper peptides.
Effects of topical copper tripeptide complex on CO2 laser-resurfaced skin: source for GHK-Cu (opens in a new tab)Randomised controlled trial · n=13 · 12 weeks
Read the paperWound Repair and Regeneration · 1994
HumanEnhanced healing of ulcers in patients with diabetes by topical treatment with glycyl-l-histidyl-l-lysine copper
Mulder GD, Patt LM, Sanders L, et al.
The strongest positive human result: a randomised, placebo-controlled trial in diabetic foot ulcers reporting better closure and fewer infections. A topical gel on open wounds, which is a genuinely different situation from cosmetic use on intact skin.
Enhanced healing of ulcers in patients with diabetes by topical treatment with glycyl-l-histidyl-l-lysine copper: source for GHK-Cu (opens in a new tab)Read the paper
Preclinical studies
1 of 3Preclinical results do not automatically hold in people.Every source behind this page85 more
- In vivo stimulation of connective tissue accumulation by the tripeptide-copper complex glycyl-L-histidyl-L-lysine-Cu2+ in rat experimental woundsMaquart FX, Pickart L, Laurent M, et al. · Journal of Clinical Investigation · 1993Preclinical
- The tri-peptide GHK-Cu complex ameliorates lipopolysaccharide-induced acute lung injury in micePark JR, Lee H, Kim SI, Yang SR · Oncotarget · 2016Preclinical
- Human skin retention and penetration of a copper tripeptide in vitro as function of skin layer towards anti-inflammatory therapyHostynek JJ, Dreher F, Maibach HI · Inflammation Research · 2010Review
- Structure of the Glycyl-L-histidyl-L-lysine--copper(II) complex in solutionFreedman JH, Pickart L, Weinstein B, et al. · Biochemistry · 1982Review
- Regenerative and Protective Actions of the GHK-Cu Peptide in the Light of the New Gene DataPickart L, Margolina A · International Journal of Molecular Sciences · 2018Review
Everything we cite for GHK-Cu, including preclinical work and early research. Each link goes to the source itself, so you can judge it rather than take our word for it.
Last updated · literature counts verified against PubMed on
Frequently Asked Questions
What has GHK-Cu been studied for?
Skin, wound healing and hair. The evidence is strongest for wound healing, where a randomised trial of a topical gel in diabetic foot ulcers reported better closure. For cosmetic skin use it is thinner than the marketing suggests: the one well-designed independent facial trial found no objective benefit. Every human study on skin used a topical form.
Do genes change how GHK-Cu works?
No study has tested whether any genotype changes response to GHK-Cu. The genes above (SOD2, COL1A1, TGFB1, SIRT1) sit on the antioxidant, collagen and repair pathways it is studied on, and some of their variants have been associated with collagen or healing traits in human studies. A DNA report can show which versions you carry and what that research does and does not show.
How does GHK-Cu differ from BPC-157?
BPC-157 is studied mostly for tendon and gut repair, and its research is almost entirely preclinical. GHK-Cu is studied mostly for skin and wound healing, and unusually for this site it has some human data, though all of it is topical. The two are often combined in commercial blends, which no study has tested as a combination.
Watch
What clinicians and researchers say about GHK-Cu
1 hr 30 minPeptide Expert: What Do Peptides Actually Do? (EXPLAINED) - Dr Alex TatemThe Diary of a CEO · PodcastBPC-157TB-500MOTS-c
2 hr 48 minPeptides: The Science, Uses & Safety | Dr. Abud BakriAndrew Huberman · ResearcherBPC-157TB-500Thymosin Alpha-1
19 minLearn Peptides So Fast it's UNREALAshley Froese · EducatorGHK-CuKPVThymosin Alpha-1Learn more about GHK-Cu
14 guides mention GHK-Cu→peptide guides
In depthGHK-Cu benefits: what the research shows about the copper peptide, and where it stops
12 min read
peptide guides
In depthHow GHK-Cu works: the copper peptide's mechanism, and what the human trials found
9 min read
comparisons
In depthGHK-Cu vs retinol vs vitamin C: what the clinical trials actually show for skin
13 min read
peptide guides
In depthGHK-Cu before and after: what the skin trials actually measured at 8 and 12 weeks
9 min read
how it works
In depthGHK-Cu and skin: why study results vary so much
8 min read
peptide guides
In depthCopper peptides for hair loss: what the GHK-Cu research can and cannot show
11 min read
Your DNA and GHK-Cu
What the research says about your variants.
The report
Which GHK-Cu variants do you carry?
Your report reads the DNA file you already have against the published research on 31 peptides, marker by marker, and says what that research does and does not show.
Read my DNA, $99