Peptide Protocol IQ
Not approved for human useHuman evidence

GHK-Cu

Also referred to as Copper tripeptide-1, Gly-His-Lys copper complex

The most credible human evidence is topical and cosmetic. Injected use is not adequately studied and should not be treated as equivalent.

Molecule class
Copper-binding tripeptide complex
Category
Dermatologic
Last evidence review
2026-08-24
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2
Human studies
1
Animal / in vitro
1
Graded claims
13
Participants

Derived from qualifying human evidence

  • Most commonly studied duration: 12 weeks. Most frequently reported duration among 1 qualifying human study with a stated duration.
  • Longest qualifying human study: 12 weeks. Longest duration among qualifying human studies with a stated duration.

These figures are computed from the study records shown below. Records without a verified source identifier are excluded from the calculation.

Mechanism

What is being studied

Binds copper(II) and has been reported in vitro to influence expression of matrix proteins including collagen, and to modulate matrix metalloproteinase activity.

Evidence

Claims, graded individually

Each statement below carries its own evidence level, its own confidence rating, and its own account of what remains unestablished. A compound does not have a single grade.

Dermatologic & Tissue Research

CPreliminaryLow confidenceHuman evidence

GHK-Cu has been reported in vitro to increase expression of collagen and other matrix proteins, with small topical human cosmetic studies reporting modest measured changes.

What is not established

Human studies are small, short, and frequently industry-sponsored. Injected use is not adequately studied and topical findings do not transfer.

Supporting sources (3)
Randomised controlled trialHuman Identifier verified

Effect of a copper tripeptide on postoperative wound healing after carbon dioxide laser resurfacing

Multiple · Archives of Facial Plastic Surgery · 2006 · n = 13

Population
Adults following full-face CO2 laser resurfacing
Endpoint
Erythema resolution, wrinkle and skin-quality measures
Route
Topical
Quantity as reported
Topical copper tripeptide formulation
Frequency
As specified in the trial protocol
Duration
12 weeks

Result. No significant difference on any objective endpoint. Only subjective patient satisfaction differed.

Adverse events. None significant reported.

Limitations. Thirteen participants, topical, and negative on everything measured objectively. There is no published human trial of injected GHK-Cu at any amount.

PMID16847171DOI10.1001/archfaci.8.4.252
In-vitro studyIn vitroNo verified identifier on file

GHK-Cu in dermal matrix remodelling and wound-healing research

Multiple (including Pickart and colleagues) · Various dermatology and biochemistry journals · 2022

Population
Human fibroblast culture and small topical human studies
Endpoint
Collagen synthesis markers, skin density, wrinkle measures
Route
Topical in the human work
Quantity as reported
Topical formulations at low percentage concentrations
Frequency
Varies
Duration
12 weeks

Result. In-vitro work reports increased collagen and matrix protein synthesis. Small topical human cosmetic studies report modest measured changes.

Adverse events. Topical irritation reported in some cosmetic studies.

Limitations. Human evidence is small, often industry-sponsored cosmetic studies with short duration. Topical findings do not transfer to injected use, which is not adequately studied.

Search PubMed for this literature →
Systematic reviewHuman Identifier verified

Peptide therapeutics in musculoskeletal medicine: a review of the evidence

Multiple · American Journal of Sports Medicine · 2026

Population
Review of the published literature on peptides marketed for musculoskeletal use
Endpoint
State of the evidence for musculoskeletal indications

Result. Concludes that no clinical data support the use of GHK-Cu for musculoskeletal conditions, that CJC-1295 and ipamorelin synergy data is murine only, that tesamorelin has no supporting orthopaedic evidence, and that for the class generally the indications, amounts, frequency and duration of treatment remain unknown.

Adverse events. Not an outcome of the review.

Limitations. A narrative review, not a meta-analysis. It is catalogued because it is the most recent peer-reviewed statement of how thin this evidence base is, and because it is the counterweight to every vendor page that implies otherwise.

PMID41476424DOI10.1177/03635465251357593

Last evidence review: 2026-08-23

Human evidence

2 human studies catalogued

Human and non-human evidence are kept strictly separate. They are never pooled, averaged, or presented as a single body of support.

Randomised controlled trialHuman Identifier verified

Effect of a copper tripeptide on postoperative wound healing after carbon dioxide laser resurfacing

Multiple · Archives of Facial Plastic Surgery · 2006 · n = 13

Population
Adults following full-face CO2 laser resurfacing
Endpoint
Erythema resolution, wrinkle and skin-quality measures
Route
Topical
Quantity as reported
Topical copper tripeptide formulation
Frequency
As specified in the trial protocol
Duration
12 weeks

Result. No significant difference on any objective endpoint. Only subjective patient satisfaction differed.

Adverse events. None significant reported.

Limitations. Thirteen participants, topical, and negative on everything measured objectively. There is no published human trial of injected GHK-Cu at any amount.

PMID16847171DOI10.1001/archfaci.8.4.252
Systematic reviewHuman Identifier verified

Peptide therapeutics in musculoskeletal medicine: a review of the evidence

Multiple · American Journal of Sports Medicine · 2026

Population
Review of the published literature on peptides marketed for musculoskeletal use
Endpoint
State of the evidence for musculoskeletal indications

Result. Concludes that no clinical data support the use of GHK-Cu for musculoskeletal conditions, that CJC-1295 and ipamorelin synergy data is murine only, that tesamorelin has no supporting orthopaedic evidence, and that for the class generally the indications, amounts, frequency and duration of treatment remain unknown.

Adverse events. Not an outcome of the review.

Limitations. A narrative review, not a meta-analysis. It is catalogued because it is the most recent peer-reviewed statement of how thin this evidence base is, and because it is the counterweight to every vendor page that implies otherwise.

PMID41476424DOI10.1177/03635465251357593

Preclinical evidence

Animal and in-vitro research

Kept separate deliberately. Most preclinical findings do not translate to humans, and animal quantities expressed per kilogram do not convert to human quantities by simple arithmetic.

In-vitro studyIn vitroNo verified identifier on file

GHK-Cu in dermal matrix remodelling and wound-healing research

Multiple (including Pickart and colleagues) · Various dermatology and biochemistry journals · 2022

Population
Human fibroblast culture and small topical human studies
Endpoint
Collagen synthesis markers, skin density, wrinkle measures
Route
Topical in the human work
Quantity as reported
Topical formulations at low percentage concentrations
Frequency
Varies
Duration
12 weeks

Result. In-vitro work reports increased collagen and matrix protein synthesis. Small topical human cosmetic studies report modest measured changes.

Adverse events. Topical irritation reported in some cosmetic studies.

Limitations. Human evidence is small, often industry-sponsored cosmetic studies with short duration. Topical findings do not transfer to injected use, which is not adequately studied.

Search PubMed for this literature →

Pharmacology

Reported parameters

Half-life

Not characterised

Systemic pharmacokinetics for injected use are not adequately characterised.

Routes studied

  • Topical
  • In-vitro

Evidence from one route does not transfer to another. Topical, oral, and injected administration can produce entirely different exposure from the same quantity.

Regulatory status

Present in cosmetic products under cosmetic regulation. Injectable preparations are not approved. FDA removed GHK-Cu from the Category 1 list effective 22 April 2026 after the nominators withdrew. A further advisory committee meeting covering GHK-Cu is scheduled before 28 February 2027.

Storage as documented

Topical cosmetic products follow their own labelling.

Safety

Signals reported in the literature

This lists what has been reported. It is not a complete safety profile, and for several compounds in this catalogue no systematic safety surveillance exists at all.

  • Topical irritation reported in cosmetic studies
  • Copper load with repeated systemic administration is a theoretical concern that is not resolved in the literature

Limitations

What the evidence cannot tell you

Given as much prominence as the findings, because for most compounds in this category it is the more important half.

  • Human evidence is small, short, cosmetic, and frequently industry-sponsored
  • Topical findings do not transfer to injected use

Reference

Evidence grading key

AStrong

Multiple high-quality human trials, or strong systematic-review or meta-analytic evidence.

BModerate

Human controlled evidence exists, but replication or sample size is limited.

CPreliminary

Small human studies, observational evidence, or early-phase clinical work.

DPreclinical

Predominantly animal or in-vitro evidence. No adequate human outcome data.

EMechanistic

Biological plausibility or mechanistic reasoning without adequate outcome evidence.

XInsufficient / conflicting

Evidence is absent, irreconcilable, or too weak to support any directional statement.

Related

Other compounds studied in the same research areas

Melanotan II

Retained in the catalogue primarily to document a substantial body of reported harm. The published case literature is the relevant evidence here.