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cosmetic · healing

GHK-Cu

Also known as: copper tripeptide-1, copper peptide, Cu-GHK, glycyl-L-histidyl-L-lysine copper(II), GHK-Copper, copper tripeptide complex

Human RCT draft

The copper(II) complex of the human tripeptide glycyl-histidyl-lysine, sold mainly as a cosmetic ingredient for skin firmness and repair and, on the grey market, as an injectable. This entry describes the copper complex, not the bare peptide: GHK and GHK-Cu are different substances and are constantly discussed as one. Most of the English-language enthusiasm comes from review articles by a single commercially affiliated author; the one randomised human trial found nothing on its objective endpoints.

Sequence
GHK

Gly-His-Lys · 3 residues · 340.38 Da (computed)

Lysine at position 3 (terminal).

single source C14H21CuN6O4- 400.90 Da (published)

Sequence source: PubChem CID 139035031, synonym 'Gly-His-Lys', corroborated by the MeSH Supplementary Concept 'glycyl-histidyl-lysine'. The record's formula is C14H21CuN6O4- while the bare tripeptide computes to C14H24N6O4; that difference is the copper plus the protons it displaces, which the resolver classified as a metal complex, not a conflict. The record describes the chelate this entry is about.

Claimed vs established

Mechanism

Claimed

Delivers copper into cells and signals tissue remodelling — raising collagen, elastin and glycosaminoglycan synthesis, stimulating angiogenesis and nerve outgrowth, and resetting gene expression toward a younger pattern.

Actually established

That GHK binds Cu(II) tightly is settled coordination chemistry and is what makes the complex a distinct substance from the peptide. Everything downstream of that — collagen synthesis, gene-expression resetting, tissue remodelling — is reported from cell culture and summarised largely in review articles by one commercially affiliated author. It has not been established that these effects occur in human skin at concentrations reachable from a topical product.

Honest appraisal

How good is the evidence

Human RCT 1 human RCTs · 1 human trials · 0 animal

There is one randomised human trial, and it is the least flattering source on this page: in 13 patients whose skin had been resurfaced with a CO2 laser, blinded evaluators and computer analysis found no significant benefit from a GHK-Cu regimen on redness, wrinkles or skin quality, while patients who used it rated their own skin quality higher. Beside that sits a body of cell-culture work and a set of review articles, three of them by the same commercially affiliated author, which describe a wide range of favourable actions. The tier ceiling of A on this page comes from a null result — the design was strong, the finding was not.

Where this evidence comes from

Three of the reviews cited here share a first author, L. Pickart, affiliated with a skin-biology research company in Bellevue, Washington; those papers declare no conflict of interest, and the reader can weigh that alongside the affiliation. The randomised trial comes from an unrelated group of facial plastic surgeons, and the coordination-chemistry work from an unrelated Polish group.

What is said vs what was shown

Claims, one at a time

Each claim carries its own evidence tier. A compound is never simply "well studied" — some of its claims may be, others not at all.

ClaimVerdictEvidenceBasis
Speeds recovery and reduces redness after laser skin resurfacing contradicted Human RCT Tested directly in the one randomised trial found: computer analysis and blinded evaluators found no statistically significant difference between groups in resolution of post-treatment erythema. Thirteen patients completed the study, which is small enough that a modest real effect could be missed — this is a null result in an underpowered trial, not a demonstration that the effect is zero.
Improves wrinkles and overall skin quality mixed Human RCT In the same trial, blinded objective assessment found no between-group difference in wrinkles or overall skin quality at 12 weeks, while a validated patient questionnaire showed significantly higher satisfaction with overall skin quality among GHK-Cu users (P = .04). The measurement that could not be influenced by knowing the treatment showed nothing; the one that could showed a difference.
Remodels tissue, raises collagen and supports wound healing mixed In vitro Repeatedly reported in cell-culture systems and gene-expression datasets, and summarised in reviews by the peptide's principal proponent. The underlying observations are real in-vitro findings; the leap from them to skin repair in a person is where the evidence stops, and the one human trial that looked did not find it.
Acts as a copper delivery molecule supported Mechanistic Supported as chemistry, not as biology. GHK forms well-characterised Cu(II) complexes, including ternary complexes with physiological ligands, which is exactly what a copper carrier would have to do. That the complex forms says nothing about where the copper ends up in a person, or whether that is beneficial.
Penetrates skin to reach living tissue when applied topically untested Mechanistic A 2025 review poses this as an open methodological question — whether skin permeation of liposome-encapsulated GHK-Cu can currently be measured reliably at all. No human permeation measurement establishing that intact complex reaches the dermis was found.
Primary sources

The studies themselves

StudyDesignSubjectsQuality
Effects of topical copper tripeptide complex on CO2 laser-resurfaced skin.
Miller TR, Wagner JD, Baack BR, Eisbach KJ · Archives of facial plastic surgery · 2006 PMID 16847171 		rct / human 13 — Patients undergoing circumoral CO2 laser skin resurfacing at standard settings Human RCT
risk of bias: moderate
Regenerative and Protective Actions of the GHK-Cu Peptide in the Light of the New Gene Data.
Pickart L, Margolina A · International journal of molecular sciences · 2018 PMID 29986520 		narrative_review / mixed In vitro
risk of bias: high
GHK Peptide as a Natural Modulator of Multiple Cellular Pathways in Skin Regeneration.
Pickart L, Vasquez-Soltero JM, Margolina A · BioMed research international · 2015 PMID 26236730 		narrative_review / mixed In vitro
risk of bias: high
Ternary Cu(II) Complex with GHK Peptide and Cis-Urocanic Acid as a Potential Physiologically Functional Copper Chelate.
Bossak-Ahmad K, Wiśniewska MD, Bal W, Drew SC, Frączyk T · International journal of molecular sciences · 2020 PMID 32867146 		in_vitro / unknown Mechanistic
risk of bias: low
Are We Ready to Measure Skin Permeation of Modern Antiaging GHK-Cu Tripeptide Encapsulated in Liposomes?
Ogórek K, Nowak K, Wadych E, Ruzik L, Timerbaev AR, Matczuk M · Molecules (Basel, Switzerland) · 2025 PMID 39795193 		narrative_review / mixed Mechanistic
risk of bias: unclear
What we do not know
  • Only one randomised human trial was found, it had 13 completers, and its objective endpoints were null — so the size of any real effect in humans is unestablished in either direction.
  • No study found here establishes how much intact GHK-Cu, if any, reaches living skin from a topical product; a 2025 review treats even the measurement as an open problem.
  • No human study of injected GHK-Cu was found, for efficacy, safety or pharmacokinetics.
  • No study measured systemic copper status after repeated topical application.
  • GHK and GHK-Cu are routinely discussed as one substance, and no study found here compares the free tripeptide against the copper complex for the same outcome.
  • No dose or product concentration from any cited study is recorded here, because no full text has been read.