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What it is
A naturally occurring tripeptide that binds copper ions with high affinity. Present in human plasma, with levels that decline with age.
How it is proposed to work
Proposed roles in extracellular matrix remodelling, collagen synthesis signalling and antioxidant defence, largely through copper delivery and effects on matrix metalloproteinases.
Approved medical uses
None as a medicine. It is permitted as a cosmetic ingredient in several jurisdictions, which is a materially different regulatory category.
Human research
Each entry states what the study found and, separately, what it cannot show.
- Randomised controlled trial2006n = 13
Randomised trial of topical GHK-Cu after CO2 laser resurfacing
Finding. Negative on its objective endpoints. Blinded evaluators and computer analysis found no difference between groups in resolution of post-treatment erythema, and no between-group difference in wrinkles or overall skin quality at 12 weeks — both groups improved. The only result favouring GHK-Cu came from the patient questionnaire, on self-rated improvement in overall skin quality.
Limitation. Thirteen completers and twelve weeks of follow-up. The skin studied was healing from circumoral CO2 laser resurfacing, not ordinary facial skin, so it says nothing about routine cosmetic or anti-ageing use. The single positive result is patient-reported; blinding is described for the erythema evaluators, not for the patients rating their own skin. This is one trial, not a body of randomised topical evidence, and it does not show objective benefit.
Preclinical research
Animal and laboratory work. Useful for generating hypotheses; it cannot establish that something works in people.
No preclinical studies catalogued.
Potential safety concerns
- WatchPreliminary
Topical use is generally well tolerated. Injected or systemic use raises copper-load questions that topical data cannot answer.
Known interactions and contraindication considerations
- Copper status interactions are theoretically relevant for systemic use; unstudied.
This list is not exhaustive and is not a substitute for a clinician reviewing your full medication history.
Regulatory status
Status is shown per jurisdiction and is accurate only as of the date stated. Where a compound is approved, the approval is bound to a specific formulation, manufacturer and indication — shown in the detail column.
| Jurisdiction | Standing | Detail |
|---|---|---|
United States FDA | Listed as of 1 Jun 2026 | Used as a cosmetic ingredient. Cosmetic ingredient status is not drug approval and permits no therapeutic claim. |
European Union EMA | Listed as of 1 Jun 2026 | Regulated as a cosmetic ingredient subject to cosmetic regulation, not as a medicine. |
India CDSCO | Listed as of 1 Jun 2026 | Cosmetic use. Any injectable presentation would fall outside this and under drug regulation. |
How it is being used
What the grey community actually runs, the reasoning they give, and our read on whether it follows from known biology. This is observation, not evidence, and not a recommendation.
Topical skin, and scalp use for hair
What is run
Applied as a serum, daily or on alternate days, often after microneedling. Scalp application for hair typically runs alongside established treatments rather than replacing them.
Their mechanistic reasoning
That copper delivery and effects on matrix metalloproteinases support extracellular matrix remodelling and collagen synthesis, and that microneedling overcomes the penetration limit imposed by the molecule's size.
Reported in the community’s own terms. Not our position.
Stacked with
- Microneedling—To overcome penetration limits. Changes the risk profile of the formulation.
- Retinoids—Commonly combined, though often separated across sessions.
- Minoxidil, for scalp use—Added alongside a treatment that has real evidence, rather than instead of it.
Regimen shape
- Dose
- figure withheld
- Scale
- Formulation percentage, not a systemic dose
- Route
- Topical serum; scalp application for hair
- Frequency
- Daily or alternate days
- Timing
- Often evening; post-procedure when combined with needling
- Duration
- Ongoing, months
Our read
For topical use on intact skin this is among the better-reasoned practices in this library — there are small human studies, the mechanism is characterised, and the effect claimed is modest and proportionate. The microneedling combination is a different question: it works by bypassing the barrier that decides what enters, which raises the stakes on formulation sterility and preservatives considerably. Hair claims are substantially weaker than skin claims and mostly extrapolated.
What the community reports
The comparison is between how sure the community is and how much is actually known — evidence strength, not direction. A compound can have solid research that came out negative.
Well regarded in skincare communities, where the discussion is generally more measured and evidence-aware than in peptide forums. Claims made for skin are more modest and better supported than claims made for hair.
Commonly reported as helping
- Improved skin texture and firmness over months
- Reduced fine lines, reported modestly rather than dramatically
- Faster healing of blemishes and post-procedure redness
- Some reports of improved hair density, generally alongside other treatments
Also reported, when it goes wrong
- Irritation, particularly combined with retinoids or acids
- Formulation instability and colour change
- Little or no effect reported by many
- Hair claims widely regarded as weaker than skin claims, within the community itself
Why these reports can mislead
Skincare results are assessed by the person who bought the product, in different lighting, months apart, usually while also changing other steps in a routine. Hair reports are worse still, because almost nobody uses it as the only intervention.
Direct quotations are not published here yet. We will only carry verbatim reports once they are sourced, dated and checked — an unattributed quote is a testimonial, and testimonials are exactly what this section exists to replace.
Watch for, in this use specifically
- Post-procedure application needs a formulation intended for it. Preservatives safe on intact skin are not necessarily safe in the dermis.
- Injected or mesotherapy use is a different risk category and needs a clinician.
- Cosmetic ingredient status is not drug approval and supports no therapeutic claim.
Active clinical trials
No registered trials currently tracked for GHK-Cu.
What remains unknown
The questions that would change our assessment if they were answered.
- How much active peptide actually penetrates intact skin from a typical formulation?
- Do measured skin-parameter changes translate into outcomes users notice over years?
References
Editorial change history
When we change a grade or a regulatory note, we log it here rather than editing quietly.
Clarified that cosmetic listing is not drug approval.
Spotted something wrong? Tell us — we publish corrections.