GHK-Cu (copper tripeptide-1)

A three-amino-acid peptide, glycyl-L-histidyl-L-lysine, bound to copper. On cosmetic labels it appears as Copper Tripeptide-1. PubChem gives the free peptide the formula C14H24N6O4 and a weight of 340.38 g/mol.

Sold as

Applied to the skin (serum, cream)

Legal status in the EU

A cosmetic ingredient under EU Regulation 1223/2009, with no approval needed before sale. The Cosmetic Ingredient Review panel judged in 2014 that copper tripeptide-1 and related tripeptide-1 ingredients are safe at the levels used in cosmetics, typically under 10 ppm. The Swedish Medical Products Agency supervises cosmetics but does not approve products in advance. Injecting it is not covered by cosmetics rules and is not an approved use in the EU. Claims about wound healing or tissue regeneration are medical claims and do not belong on a cosmetic product.

GHK binds copper and is thought to work as a carrier that brings copper into cells. According to the US Cosmetic Ingredient Review panel the GHK sequence is a fragment of type I collagen; Pickart and Margolina place it more specifically in the alpha-2(I) chain. In cell culture the complex has been reported to increase production of collagen and other structural components of skin. The gene-activity data that gets quoted so often comes from the Broad Institute's Connectivity Map, a library built on cultured cell lines — not skin, and not people.

Part of the bodyWhat happensHow it is knownKind of evidence

Skin that has just been lasered

Nothing measurable happened. Faces resurfaced with a carbon-dioxide laser were treated afterwards either with a skin-care routine containing GHK-Cu or with the same routine without it. Redness faded, wrinkles improved and skin quality improved in everyone, at the same rate in both groups. The one thing that differed was what the patients themselves said about their skin.

Measured in 13 patients over 12 weeks. The trial was randomised, the assessors did not know which group a patient was in, and photographs were analysed by computer as well.

One small study

Source [01]

An open foot ulcer

This is the one place a measured, objective difference has been reported. In people with diabetes who had lost feeling in their feet and had ulcers on the sole, a gel containing GHK-Cu closed the wounds faster than the identical gel without it. Among the ulcers treated straight after the wound was cleaned out, fewer became infected.

Measured in a multicentre randomised trial in which the assessors did not know which gel a patient had. Everyone also got the wound cleaned out at the start, pressure-relieving footwear and diabetes education. The published abstract does not state how many patients took part or over how many weeks. It was published in 1994 and has not been repeated.

One small study

Source [07]

The immune system and the liver, in animals given the copper-free peptide

This is the part of the story that almost never gets quoted, and it is the part that matters for anyone injecting it. In mice and rats given repeated injections into the abdominal cavity, the peptide damped down the animals' antibody response to a foreign substance, and the more they were given the more it was damped down. Liver cells started dividing faster, and at the two highest amounts the liver showed signs of degenerating.

Measured in CBA mice and Wistar rats, given ten injections a day apart, at 0.5, 1.5, 5, 50, 150 and 450 milligrams per kilogram of body weight. The report does not say how many animals were used. Everything from 1.5 milligrams per kilogram upwards suppressed the antibody response and sped up liver-cell division; the lowest amount did neither. The US Cosmetic Ingredient Review panel lists this work under the copper-free peptide, not the copper complex, and nobody has looked for any of it in a person.

Only seen in animals

Source [03]

The bloodstream, if any of it gets there

It does not last. Injected into a vein, the peptide is broken down quickly into a two-amino-acid fragment, and that fragment is itself cleared from the blood quickly.

Measured in male rats given 10 milligrams per kilogram of the copper-free peptide into the tail vein, with blood sampled for 60 minutes afterwards. The report does not say how many rats were used. The same panel report notes that the peptide is unstable in human plasma in the laboratory and is broken down rapidly by enzymes that trim amino acids off the end of a peptide. No measurement of GHK-Cu in the blood of a person who has been given it has been published.

Only seen in animals

Source [03]

The skin, when a solution is left on it

Copper from the peptide does cross skin in a laboratory rig, and a large amount also stays behind in the skin itself. The measurement was made on donated human skin mounted in a rig, not on a living person. The authors concluded that useful amounts of copper had been delivered.

Measured on pieces of donated human skin held in flow-through diffusion cells for 48 hours, using a 0.68 per cent water solution. Through skin sliced to a set thickness, about 136 micrograms of copper crossed each square centimetre over the 48 hours, and about 97 micrograms per square centimetre stayed in the tissue. Two thinner skin preparations were also tested, but the published abstract gives no figures for them.

Only seen in a dish, not in a body

Source [08]

The scalp and hair

Hair regrowth is one of the main things GHK-Cu is sold for and it is the claim with the least behind it. No published trial has given GHK-Cu on its own to people with hair loss.

The nearest human study randomised 45 men with male-pattern hair loss to a product combining 5-aminolevulinic acid with glycyl-histidyl-lysine, or to a dummy, once a day for six months. The paper does not say whether the peptide carried copper, and the effect of the peptide cannot be separated from the other ingredient. The laboratory hair-follicle experiment that is quoted for copper peptides used AHK-Cu, a different copper peptide with a different first amino acid, on human follicles and on cells in dishes.

Claimed, never tested

Source [09]Source [10]

The only randomised comparison indexed in PubMed is Miller and colleagues (2006) in Archives of Facial Plastic Surgery: 13 patients after CO2 laser resurfacing, followed for 12 weeks. Computer analysis and blinded assessors found no statistically significant difference from the control in redness, wrinkles or skin quality; only the patients' own rating of their skin quality was significantly higher (p = 0.04). The widely cited Leyden 2002 studies in 71 and 41 women cannot be found as peer-reviewed full papers in PubMed. The most widely circulated review, Pickart and Margolina 2018, is written by two authors listing an affiliation with Skin Biology, a company that sells copper peptides; the paper simultaneously declares no conflict of interest.

In the laser trial the patients were assessed 12 weeks after treatment, and the objective measurements never separated from the control group. In the 1994 ulcer trial the wounds closed roughly three times faster than with the gel that had no peptide in it, but the published abstract does not say over how many weeks. The hair-loss trial of the combination product ran for six months. In the laboratory, copper crossed donated human skin over the 48 hours it was measured. Nothing has been measured in a person beyond six months, and that six months was a combination product rather than GHK-Cu on its own.

What was measuredWhat happenedIn whomHow it is known

How much of a diabetic foot ulcer had closed

The middle patient's ulcer had closed by 98.5 per cent, against 60.8 per cent for the identical gel without the peptide (p < 0.05). Wounds closed about three times faster. For ulcers that started bigger than a square centimetre the gap was wider: the middle wound closed by 89.2 per cent, while the middle control wound got 10.3 per cent bigger (p < 0.01).

People with diabetes and ulcers on the sole of the foot caused by nerve damage, in a multicentre randomised trial with blinded assessors. The published abstract states neither the number of patients nor the length of treatment.

One small study

Source [07]

Ulcers that became infected

Among the ulcers treated straight after the wound was cleaned out, 7 per cent of those on the peptide gel became infected, against 34 per cent of those on the gel without it (p < 0.05).

The same 1994 trial in people with diabetic foot ulcers. The number of patients is not given in the published abstract.

One small study

Source [07]

Redness, wrinkles and skin quality after laser resurfacing

No statistically significant difference from the control on any objective measure — not redness clearing sooner, not wrinkles, not overall skin quality. Both groups improved equally. The only difference was on the questionnaire: patients using GHK-Cu rated their own skin quality as more improved (p = 0.04).

13 patients after carbon-dioxide laser resurfacing of the skin around the mouth, followed for 12 weeks.

One small study

Source [01]

Hair count, for a combination product containing the peptide rather than for GHK-Cu itself

Hair count rose by 52.6 hairs in the group on the stronger solution and by 71.5 in the group on the weaker one, against 9.6 in the dummy group. Both rises within the active groups were statistically significant. Only the weaker group beat the dummy group when the two were compared directly (p < 0.05). Hair length and thickness did not differ between any of the groups, and no side effects were reported in any group.

45 men with male-pattern hair loss, split across three groups and treated once a day for six months with a combination of 5-aminolevulinic acid and glycyl-histidyl-lysine peptide, or with a dummy. The paper does not state whether the peptide carried copper, and it does not separate the peptide's effect from the other ingredient's.

One small study

Source [09]

Copper crossing donated human skin in the laboratory

About 136 micrograms of copper crossed each square centimetre of skin sliced to a set thickness over 48 hours, and about 97 micrograms per square centimetre stayed in the tissue. There was no comparison group: this is a measurement of how much got through a piece of skin, not a comparison between two treatments.

Pieces of donated human skin held in flow-through diffusion cells, not living people. A 0.68 per cent water solution, 48 hours.

Only seen in a dish, not in a body

Source [08]

At the low levels used in cosmetics the risk of irritation is low, and the review panel found no safety objections. Free GHK is broken down by enzymes in the blood, which limits how relevant it can be beyond the skin. The real weakness is the documentation: the effect data rests largely on conference material and supplier reports, while the one blinded, objective measurement indexed in PubMed was negative. GHK-Cu is not named on the 2026 WADA list, but the S2.3 growth factor category is written so that it is not exhaustive.

EffectWhat it feels likeHow often

A weaker antibody response, and a damaged liver — seen in mice and rats given the copper-free peptideSerious

Mice and rats were given ten injections into the abdominal cavity, one a day, at 0.5, 1.5, 5, 50, 150 and 450 milligrams per kilogram of body weight. From 1.5 milligrams per kilogram upwards the animals made fewer antibodies against a foreign substance and their liver cells divided faster. At 150 and 450 milligrams per kilogram the liver showed signs of degenerating, worse at the higher amount. These are abdominal injections in rodents, using the peptide without copper attached, and they are not comparable to a serum on a face. Nobody has looked for either effect in a person, by any route.

Never measured in a person. In the animal experiments, every amount above the lowest one tested suppressed the antibody response.

Source [03]

Stinging or redness where it is put on

The nearest hard measurement is a laboratory one. Human skin cells were exposed to GHK-Cu and to two plain copper salts across a very wide range of concentrations, from 0.0058 to 5,800 micromolar. Eight markers that cells use to signal irritation were measured after 24 hours. GHK-Cu killed no cells and changed none of the eight markers significantly. At two of the concentrations tested, the two plain copper salts switched four of the markers on without killing cells. The authors concluded that binding copper to the peptide is a gentler way of getting copper into skin than the salts are.

Not measured. No published trial of GHK-Cu counted how many people got irritated skin. The 2006 laser trial did not report it, and the 2016 hair trial of a combination product reported no side effects in any of its three groups of men over six months.

Source [09]Source [11]

An allergic reaction to the copper itself

A patch test is a small amount of a substance taped to the skin for two days to see whether the immune system reacts. The reviewers call copper a very weak trigger compared with other metals, but one that can still produce a genuine allergic reaction in a few selected cases. No one has patch-tested GHK-Cu specifically at the scale that would give it its own number.

Across the studies pulled together in a 2014 review, a weighted average of 3.8 per cent reacted to copper. Those were people already suspected of a metal reaction or a related exposure, not a general sample, and the figure is for copper in general rather than for GHK-Cu.

Source [12]

These are the amounts the studies below gave their participants, and they are here as facts about those studies. They are not a recommendation, not a starting point and not a range to pick from. What a person should take, if anything, is a question for a doctor who knows them.

Miller 2006, skin care after carbon-dioxide laser resurfacing of the face, 13 patients

A skin-care regimen containing the copper tripeptide complex, applied to the resurfaced skin. The published abstract does not state the concentration or how often it was applied.

Patients were assessed 12 weeks after treatment

Source [01]

Mulder 1994, diabetic foot ulcers — the trial that reported faster wound closure

A measured dose of Iamin Gel, containing glycyl-L-histidyl-L-lysine copper, applied to the ulcer once a day on top of standard wound care. The published abstract does not state the concentration.

Not stated in the published abstract

Source [07]

Annals of Dermatology 2016, male-pattern hair loss, 45 men — a combination product, not GHK-Cu on its own

A solution of 5-aminolevulinic acid with glycyl-histidyl-lysine peptide, at 100 milligrams per millilitre in one group and 50 milligrams per millilitre in another, applied once a day. A third group got a dummy. The paper does not state whether the peptide carried copper.

6 months

Source [09]

What people report

• Whether GHK-Cu does anything at all when injected into a person: no study of any kind, at any amount, has been published.
• Whether a serum put on a face reaches the living layers of skin in a living person — the only measurement was on donated skin in a laboratory rig.
• How many patients were in the 1994 diabetic ulcer trial, and over how many weeks they were treated: the published abstract gives neither, and the trial has not been repeated in more than thirty years.
• What GHK-Cu does to skin beyond 12 weeks, which is as far as the 2006 laser trial followed anyone.
• How much copper builds up in someone who uses it on the skin every day for years.
• Whether the copper-bound form behaves like the copper-free one inside the body: the injected animal work and the blood measurements both used the peptide without copper attached.
• Whether the suppressed antibody response and the liver damage seen in injected rodents happen in people: nobody has looked.
• What GHK-Cu on its own does to hair — the one controlled human trial used it combined with another compound, and the laboratory follicle study used a different copper peptide.
• How it compares with any established skin treatment: neither published human trial had an active comparison group, only an inactive one.
• What is actually in a vial or a serum bought outside the cosmetics supply chain, since nothing outside that chain is tested for identity or purity.

Is GHK-Cu approved for anything?

Not as a medicine. It is a cosmetic ingredient. In 2014 the US Cosmetic Ingredient Review panel judged copper tripeptide-1 and related ingredients safe as they are currently used in cosmetics. The panel noted that typical concentrations are under 10 parts per million, and that the safety tests it reviewed were negative. That is a judgement about not doing harm in a face cream, not a finding that it does anything. A peer-reviewed 2025 review of tripeptides in wound healing lists "lack of clinical trial data" for GHK-Cu as one of the field's limitations.

Source [03]Source [13]

Does a copper peptide serum actually reach the collagen underneath?

Nobody has measured that in a living person. The one direct measurement used donated human skin held in a laboratory rig for 48 hours. About 136 micrograms of copper crossed each square centimetre of skin that had been sliced to a set thickness, and about 97 micrograms per square centimetre stayed in the tissue. The authors concluded that useful amounts of copper had been delivered, which is a statement about a rig rather than about a face.

Source [08]

Where does the claim that it resets 31 per cent of your genes come from?

From one review. It reports that GHK moved 31.2 per cent of human genes up or down by at least half, with 59 per cent of those going up and 41 per cent going down. The underlying data is from the Broad Institute's Connectivity Map, a library of gene responses in cultured cell lines — not skin, and not people. The same review is also the source of the often-quoted figure that blood levels of GHK fall from about 200 nanograms per millilitre at age 20 to about 80 at age 60. Both of its authors list an affiliation with a company that sells copper peptides, and the paper states that the authors declare no conflict of interest.

Source [02]

What about the studies in 71 women and 41 women that everyone cites?

They are described in that same 2018 review as a 12-week facial cream study in 71 women and a 12-week eye cream study in 41 women, both reporting firmer, thicker skin and fewer fine lines. Neither can be found as a peer-reviewed paper in PubMed. What can be found there is the 13-patient laser study from 2006, which was negative on every objective measure, and the 1994 ulcer trial, which was positive and has never been repeated.

Source [01]Source [02]

Has anyone studied injecting it?

No published study has given GHK-Cu to a person by injection. The two studies of this compound on the US trial registry are both applied to the outside of the body. One is a phase 2 trial of a 0.1 per cent gel on standardised skin wounds in 60 healthy adults, which started on 2 February 2026, is recruiting, and has posted no results. The other is a study of a stick-on patch that its manufacturer says raises the body's own GHK levels; it has not started recruiting and is scheduled to begin in January 2027.

Source [14]Source [15]

I have seen a cream study with 39 per cent shorter wrinkles. Was that this?

No. That result is for palmitoyl tripeptide-1, which is the same three amino acids with a fatty tail attached and no copper. A cream containing 3 parts per million of it was used around the eyes of 15 women, twice a day for four weeks. Against a dummy cream it gave 39 per cent shorter wrinkles, 23 per cent shallower wrinkles and 17 per cent less roughness. A separate 4 parts per million preparation increased skin thickness by about 4 per cent in 23 women over four weeks. Neither tested GHK-Cu.

Source [03]

Each letter represents one amino acid.

1. [01]Miller TR m.fl. Effects of topical copper tripeptide complex on CO2 laser-resurfaced skin. Arch Facial Plast Surg 2006;8(4):252-9 (13 patienter; inga signifikanta objektiva skillnader) (2006)
2. [02]Pickart L, Margolina A. Regenerative and Protective Actions of the GHK-Cu Peptide in the Light of the New Gene Data. Int J Mol Sci 2018;19(7):1987 (both authors list an affiliation with R&D Skin Biology) (2018)
3. [03]CIR: Safety Assessment of Tripeptide-1, Hexapeptide-12, their Metal Salts and Fatty Acyl Derivatives, and Palmitoyl Tetrapeptide-7 as Used in Cosmetics (Final Report, 30 juni 2014) (2014)
4. [04]PubChem: glycyl-L-histidyl-L-lysin (GHK) – C14H24N6O4, 340,38 g/mol
5. [05]Swedish Medical Products Agency: rules for cosmetics — market supervision, no approval before sale (in Swedish)
6. [06]WADA: World Anti-Doping Code International Standard – Prohibited List 2026 (i kraft 1 januari 2026) (2026)
7. [07]Mulder GD et al. Enhanced healing of ulcers in patients with diabetes by topical treatment with glycyl-L-histidyl-L-lysine copper. Wound Repair Regen 1994;2(4):259-69 (1994)
8. [08]Hostynek JJ, Dreher F, Maibach HI. Human skin penetration of a copper tripeptide in vitro as a function of skin layer. Inflamm Res 2011;60(1):79-86 (2011)
9. [09]Efficacy of a Complex of 5-Aminolevulinic Acid and Glycyl-Histidyl-Lysine Peptide on Hair Growth. Ann Dermatol 2016;28(4):438-43 (45 men, 6 months) (2016)
10. [10]Pyo HK et al. The effect of tripeptide-copper complex on human hair growth in vitro. Arch Pharm Res 2007 (AHK-Cu, not GHK-Cu) (2007)
11. [11]Selected Biomarkers Revealed Potential Skin Toxicity Caused by Certain Copper Compounds. Sci Rep 2016 (human keratinocytes, GHK-Cu vs copper chloride and copper acetate) (2016)
12. [12]Fage SW, Faurschou A, Thyssen JP. Copper hypersensitivity. Contact Dermatitis 2014;71(4):191-201 (2014)
13. [13]Exploring the Role of Tripeptides in Wound Healing and Skin Regeneration: A Comprehensive Review. Int J Med Sci 2025;22(16):4175-4200 (2025)
14. [14]ClinicalTrials.gov NCT07437586 — Topical GHK-Cu Gel for Acute Skin Wound Healing, phase 2, 60 participants estimated, Hudson Biotech, recruiting, no results posted (2026)
15. [15]ClinicalTrials.gov NCT07706361 — effect of the X39 patch on circulating GHK and GHK-Cu levels, LifeWave Inc., not yet recruiting (2026)