Ingredient Beauty BenefitsPeptide · Copper Tripeptide-1
GHK-Cu: we found one human trial, and inside that one trial the answers split
One randomised trial with 13 completers is all this page has. After CO2 laser resurfacing, one arm used a GHK-Cu product and the other did not. Blinded raters and computer analysis found no difference in erythema, wrinkles or skin quality. Yet the patient questionnaire favoured GHK-Cu significantly (P = .04).
Last checked Sep 21, 2026
Start here
- What it is
A three-part peptide — glycine, histidine, lysine — with a copper ion attached. It occurs naturally in human plasma.
- What it is used for
Serums and creams sold on wrinkles and firmness.
- How it is said to work
Laboratory work describes it as a repair signal after injury. What that signal does in skin you apply it to is a separate question.
There are no numbers and no citations in this box. What has been established, and how far, is below.
At a glance
- In pregnancy
- Not established
- Irritation
- Minimal
- Daytime use
- ✓ Fine
- How well established
- Not established
- Concentration studied
- Not disclosed
- Length of the studies
- 12 weeks
Not a measurement — reported irritation grouped into five steps. It varies between people.
“Concentration studied” and “Length of the studies” are taken straight from the research on this page. They are not a recommended dose, and the figure for each finding is written out in the text.
This is not how large the effect is but how well confirmed it is. It shows the highest grade among the findings on this page.
GHK-Cu is the tripeptide glycyl-L-histidyl-L-lysine with a copper ion bound to it. It occurs in human plasma and is said to decline with age.
In the laboratory it is busy. There is a body of work on wound repair, collagen synthesis and inflammation.
But this page is not about the laboratory. Searching for randomised trials in people who applied it returned one. And finding it meant working past the veterinary literature — a good share of the human-sounding results for this ingredient are studies in dogs and horses.
Inside that one trial, the answers split. It depended on who was doing the measuring. We give each its own entry below.
You will have seen this shape on this site before. The PRP page is the same.
Contents
What is established
The same ingredient at a different strength, in a different formula, is a different product. These are the conditions the studies used.
Blinded raters and the computer found no difference
A 2006 trial in Arch Facial Plast Surg.
Participants had CO2 laser resurfacing around the mouth. They were then randomised to an aftercare regimen with or without a GHK-Cu product. 13 completed the study.
Three things did the measuring:
- computer software analysing post-treatment erythema
- blinded evaluators scoring erythema
- assessments at 12 weeks of overall improvement in wrinkles and overall skin quality
The results, as reported:
- Did erythema resolve sooner? No statistically significant difference between groups — not on computer analysis, not from blinded evaluators.
- Wrinkles and skin quality: every participant improved significantly, but the groups did not differ.
Read that second line again. Everyone improved. But that was because they had CO2 laser resurfacing. Adding GHK-Cu did not improve them further.
This is the work a control group does. Run this trial without one and you get the sentence 'wrinkles in people using GHK-Cu improved significantly over 12 weeks' — a sentence that is true and misleading at once.
There are 13 people. A small real difference could have been missed. This trial does not prove GHK-Cu does nothing. It goes as far as not yet visible.
- Randomised controlled trial in people · 13 participants · 12 weeks · Compared with no treatment · Funding not declared · Endpoint scores from blinded assessors PMID 16847171
Yet the patient questionnaire favoured GHK-Cu
Same trial, same 13 people.
Participants filled in a validated questionnaire before treatment and 12 weeks after.
On the questionnaire, improvement in overall skin quality was significantly greater for those using the GHK-Cu products (P = .04).
In the entry just above, blinded raters scoring 'overall skin quality' found no difference. Same people, same faces, same 12 weeks.
This is the second time this site has run into this shape.
The split-face trial on the PRP page was identical — masked dermatologists found no difference, the participants did. And on minoxidil, 2% split the other way: hair really did increase and the users could not tell.
All three say the same thing. 'It improved' cannot be read without who measured what.
This trial carries one weakness the PRP trial did not. The participants were not blinded. The control arm simply did not receive the GHK-Cu products, so they very likely knew which arm they were in. In the PRP trial both cheeks were injected, so the participants did not know.
So here 'I got the expensive one, so it looks better' is a live explanation. The design cannot rule it out.
Both entries sit at 'not established'. 13 people, no participant blinding, one trial.
- Randomised controlled trial in people · 13 participants · 12 weeks · Compared with no treatment · Funding not declared · Endpoint self-reported improvement PMID 16847171
How to use it
- The trial above used it as aftercare following a laser procedure. We did not find a randomised trial of applying it to skin that had not had a procedure.
- We do not state a concentration. The abstract does not give the GHK-Cu content of the products, and this site does not estimate concentrations it does not know.
- It is often said not to combine it with vitamin C. We could not verify the basis for that claim. Until we do, we will write neither 'avoid' nor 'it is fine'.
- If you want thick evidence for wrinkles and firmness, retinol and retinaldehyde are far thicker on this site.
Cautions
- The trial reported no adverse events attributable to this ingredient. But there were 13 people.
- It contains copper. If you have a problem with copper metabolism, check in a consultation.
- We could not find data on use in pregnancy.
- There is only one randomised trial in people. Most of the material on this ingredient is laboratory and animal work.
With a new ingredient, apply a small amount somewhere inconspicuous, such as the inner arm, for two days first. Stop if it reddens or stings.
Related skin concerns
What this article relies on
- PubMed — 미국 국립의학도서관 문헌 데이터베이스National Library of Medicine · Checked on 2026-09-16