GHK-Cu
GHK-Cu pen: injectable vs topical, what studies tested
What a pre-filled GHK-Cu pen is, why almost every human study of the copper peptide used creams and gels, and what that means when reading claims about injections.
What it is
GHK-Cu is a copper complex of a very small peptide. GHK stands for its three amino acids, glycine, histidine and lysine, and Cu is the chemical symbol for copper, which the peptide holds tightly. It was first described in 1973 in human blood plasma (Pickart 1973). Under the cosmetic name copper tripeptide-1 it appears in many skin creams and serums. A GHK-Cu pen is a pre-filled injection pen that holds the same complex already dissolved in liquid. Pens and vials of GHK-Cu are sold for research use only; injectable GHK-Cu is not an approved medicine in the EU, the UK or the United States.
The full summary of the research is in GHK-Cu: what the studies say. This page focuses on one question people ask about pens: what has actually been tested, cream or injection?
What the studies looked at
Almost all GHK-Cu research falls into four groups.
- Cells in a dish: skin fibroblasts, the cells that make collagen, exposed to tiny concentrations of GHK-Cu.
- Animals: mainly rats and mice, with wounds or lung injury.
- Gene databases: computer analyses of how GHK changes gene activity in cultured cells (Pickart 2018).
- People: a small number of trials, all with a gel or a cream on the skin. The best known followed diabetic foot ulcers treated with a GHK-Cu gel (Mulder 1994) and 13 patients after laser resurfacing (Miller 2006).
What the studies say
On skin, applied as a gel. Diabetic foot ulcers treated with the GHK-Cu gel closed by a median of 98.5 % of their area against 60.8 % with a gel without the peptide, and infections occurred in 7 % of treated ulcers against 34 % (Mulder 1994).
After laser resurfacing. Blinded evaluators and computer analysis found no difference in redness, wrinkles or overall skin quality between the GHK-Cu regimen and the comparison, although patients using GHK-Cu rated their own skin quality higher (Miller 2006).
By injection. No completed human study of injected GHK-Cu appears in the recent reviews. Every human study they list used the skin route, and one 2026 review asked for route-specific safety thresholds before any clinical use (Mateescu 2026).
What the researchers flagged
- The human evidence is thin. A 2026 systematic review described the human literature as thin and fragmented, with mostly small trials of facial creams (Najafi 2026). Another called GHK-Cu promising but unproven (Mateescu 2026).
- Creams may not reach deep. GHK-Cu dissolves in water and crosses the outer layer of the skin poorly, so reviewers question how much of a cream reaches the deeper skin (Mortazavi 2025). This is the argument usually made for injections, yet it has not been tested in a published human trial.
- Products differ. How much copper is actually bound to the peptide varies between products, and most studies did not measure it (Mateescu 2026). An independent lab report is the only way to know what a given batch contains.
The extended breakdown
| Cream or serum | Vial | Pre-filled pen | |
|---|---|---|---|
| Form | Mixed into a cosmetic base | Freeze-dried blue powder | Ready-made solution in a cartridge |
| Preparation | None | Dissolved in water first, with arithmetic | None |
| Human studies with this route | A few small trials | None published | None published |
| Regulatory frame | Cosmetic ingredient | Research use only | Research use only |
Lab reports for GHK-Cu. An independent test by Janoshik Analytical in July 2026 measured 99.795 % purity for a 100 mg GHK-Cu vial from AuraVia's supplier (verify key VHXX2QSW3ZJ6 at verify.janoshik.com). That report covers the vial, not the pen. For a pen, ask for a report tied to the pen's own batch number. How to read a Janoshik report explains each line.
Why concentration matters more than purity. Purity says what share of the sample is GHK-Cu. Concentration, in mg per ml, says how much of it is in the liquid. A pen can be very pure and still hold less peptide than its label states, which only a measured concentration would reveal.
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Extended breakdown
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Questions people ask
Has injected GHK-Cu been tested in humans?
Not in any completed human study named in the recent reviews. Every human study they list applied GHK-Cu to the skin as a cream or gel, and a 2026 review called for route-specific safety thresholds before any clinical use by injection.
Is GHK-Cu legal in cosmetics?
Yes. Copper tripeptide-1, the cosmetic name of GHK-Cu, is used in creams and serums sold in the EU and the UK. Injectable GHK-Cu is a different matter: it is not an approved medicine anywhere and is sold for research use only.
What is the difference between a GHK-Cu pen and a GHK-Cu vial?
A vial contains a freeze-dried blue powder to be dissolved in water before use. A pre-filled pen contains the peptide already in solution at a concentration fixed by the manufacturer, so nothing has to be mixed or calculated.
Why is GHK-Cu blue?
Because of the copper. GHK is the peptide; the copper ion it binds gives the complex, and its solutions, a blue colour.
What this page is, and is not
This page explains what published studies found. That is all it is. It is not medical advice, and it is not instructions for using anything. Nothing here is meant to find, treat, cure or stop any illness. The compounds discussed on this site are not approved medicines in the EU or the UK. Research compounds are sold for laboratory use only, not for use in humans or animals. A study tells you what happened to the people in it. It does not tell you what would happen to you. Talk to a doctor. This page is published by AuraVia Research Ltd, which sells research compounds.
Sources
- Pickart L, Thaler MM, Nature New Biol 1973, PMID 4349963 pubmed.ncbi.nlm.nih.gov/4349963/
- Mulder GD et al., Wound Repair Regen 1994, PMID 17147644 doi.org/10.1046/j.1524-475X.1994.20406.x
- Miller TR et al., Arch Facial Plast Surg 2006, PMID 16847171 doi.org/10.1001/archfaci.8.4.252
- Pickart L, Margolina A, Int J Mol Sci 2018, PMID 29986520 doi.org/10.3390/ijms19071987
- Mortazavi SM et al., BioImpacts 2025, PMID 39963574 doi.org/10.34172/bi.30071
- Najafi N et al., Arch Intern Med Res 2026, PMID 42787770 doi.org/10.26502/aimr.0255
- Mateescu DM et al., Pharmaceutics 2026, PMID 42797253 doi.org/10.3390/pharmaceutics18091077
Related guides
GHK-Cu: what the studies say about the copper peptide
What published studies found about the copper peptide GHK-Cu: cell and animal work, gene analyses, the few human trials, and what remains unproven.
Pens and vialsPeptide pen or vial? What changes between the two
A neutral explainer of lyophilised vials with bacteriostatic water versus pre-filled pens: stability, handling, arithmetic and dose consistency.
Lab reports DraftHow to read a Janoshik report
What a certificate of analysis from Janoshik contains, how to verify one with its key, and the four public reports behind the products named on this site.