Part of the skin and hair peptide hub: every topical and cosmetic peptide we cover, with its evidence grade.
GHK-Cu
A copper-binding tripeptide from human plasma: rich cell and animal data, two topical trials in people, none by injection
GHK is three amino acids, glycine, histidine and lysine, that circulate in human plasma and hold on to copper tightly. As GHK-Cu it is a common skin-care ingredient, and it is also sold for injection. The laboratory and animal record is large. In people, a small post-laser study found no objective skin benefit, a leg-ulcer trial found a GHK-copper cream no better than placebo, and nobody has published a trial of injecting it.
What is it?
GHK was identified in human plasma in the 1970s by Loren Pickart's group, first as a growth factor for cultured cells and then as the tripeptide glycyl-histidyl-lysine. It binds copper(II) with high affinity, and almost everything sold, studied and argued about is that copper complex, GHK-Cu. Serum levels average about 200 ng/mL at age 20 and about 80 ng/mL by 60, and that decline is the starting point for most of the anti-ageing interest.
The strongest evidence is chemical and preclinical. GHK competes with albumin for copper in plasma-like conditions and docks onto albumin itself, which may be how it travels in blood. In rat wound chambers it raised collagen and other matrix components in step with the dose. In mice it reduced lung scarring after bleomycin and muscle loss after cigarette smoke, and a rat ligament study found a benefit at six weeks that had gone by twelve.
Human evidence is thin and entirely topical. Thirteen patients completed a randomised trial of post-laser skin care with or without GHK-Cu: blinded ratings found no difference in redness, wrinkles or overall skin quality, although the GHK-Cu group rated their own skin better. An 86-patient trial in venous leg ulcers found a 0.4% tripeptide-copper cream no better than an inert placebo. A 2025 review of GHK as an anti-wrinkle ingredient pointed to a surprising lack of clinical studies and too little data on whether it gets through the skin at all.
Injection is where the gap is widest. None of the 42 papers in our evidence set tested injected GHK-Cu in people. In the US the nomination for injectable GHK-Cu was withdrawn in April 2026, so pharmacies cannot compound it for injection; other routes, such as creams, went back into FDA's Category 1 in May 2026, and FDA says it will consult its compounding advisory committee on GHK-Cu before the end of February 2027.
Mechanism of Action
Four lines of mechanism run through the abstracts. The first is chemistry done with human albumin; the others come from rodents, cultured cells and the reviews written by GHK's discoverer, and none has been confirmed by treating people.
Copper binding is chemistry and the collagen increase was in rats. The one human trial here used a skin product after laser resurfacing; injections have never been studied in people.
Each step is tagged with where it was shown. A dashed red arrow marks a link the evidence does not establish.
The pathway in words
- GHK. A three-amino-acid peptide, glycyl-histidyl-lysine, found in human plasma, with a copper affinity like albumin's copper-carrying site. Shown in: review. Source: PubMed 18644225.
- Takes copper from albumin. In solution with equal amounts of albumin it held about 42% of the copper; at normal blood concentrations about 6% sits with small molecules like it. Shown in: lab. Source: PubMed 7340824.
- More collagen in rat wounds. Injected into wound chambers in rats, GHK-Cu raised collagen, protein, DNA and glycosaminoglycans with dose; collagen rose twice as much as other proteins. Shown in: animals. Source: PubMed 8227353.
- Skin after laser treatment. In 13 patients after CO2 laser resurfacing, redness and wrinkles did not improve more with GHK-Cu products, though patients rated skin quality better. Shown in: people. Source: PubMed 16847171.
- never tested. Injected, in people. The only human trial here used products on the skin; no study has tested GHK-Cu injections in people. Shown in: people. Source: PubMed 16847171.
Copper carriage
GHK binds copper(II) tightly. At equal concentrations it took about 42% of the copper from albumin in dialysis experiments, but at blood-like concentrations only about 6% of copper sat with small molecules. GHK-copper also docks onto histidines on albumin, forming two three-way complexes, which may be how the peptide moves through the blood.
Collagen and matrix
Injected into steel-mesh wound chambers in rats, GHK-Cu raised collagen, glycosaminoglycans, DNA and total protein in proportion to the dose, and collagen synthesis rose twice as much as other proteins. Type I and III collagen mRNA went up while TGF-β mRNA did not, so the effect did not run through that growth factor.
Oxidative stress and inflammation
In mice with bleomycin-scarred lungs, GHK-Cu lowered TNF-α, IL-6 and collagen deposition through the Nrf2, NF-κB and TGF-β1/Smad pathways. In muscle cells exposed to cigarette-smoke extract it reduced the wasting markers MuRF1 and atrogin-1 and raised mitochondrial content.
Gene-expression claims
Reviews by Pickart and colleagues describe GHK as able to raise or lower at least 4,000 human genes, and credit it with anti-cancer, anti-anxiety and DNA-repair activity. The abstracts present this as gene data. They do not say it comes from treating people, and no independent human study in our set tests it.
Published Research
Our evidence set holds 42 papers on GHK-Cu, and 32 name it in their titles, which is what a study card needs. Most are reviews, chemistry, cell work and rodent studies; both human treatment trials used creams. The 14 cards below include the discoverer's own reviews, the most positive papers here, next to the trial that found no objective benefit. Three more papers, a leg-ulcer trial, a rabbit wound study and a guinea-pig wound study, are about GHK-Cu according to PubMed's substance index but do not name it in their titles, so they appear in References without a card.
Skin care after CO2 laser resurfacing
Thirteen patients completed this randomised trial of post-laser skin care with or without GHK-Cu. Computer analysis and blinded evaluators found no faster fading of redness and no difference in wrinkles or overall skin quality between the groups at 12 weeks. On a validated questionnaire, patients using GHK-Cu rated their skin quality higher (p = 0.04).
Three-way complexes with albumin
GHK-copper bound to histidines on human serum albumin, forming two ternary complexes: one at His3 (conditional binding constant 2,900 M⁻¹ at pH 7.4) and a weaker one (1,700 M⁻¹), probably at His128 or His510. The authors suggest albumin could shuttle the functional form of GHK in blood.
Competing with albumin for copper
In titration and equilibrium-dialysis experiments at pH 7.5, the tripeptide competed with albumin for copper: at equal concentrations of the two, about 42% of the copper went to the peptide. At concentrations close to those in blood, only about 6% of copper was held by small molecules, the peptide included.
More collagen in rat wound chambers
Rats had steel-mesh cylinders implanted under the skin and injected with saline or GHK-Cu. GHK-Cu raised dry weight, DNA, protein, collagen and glycosaminoglycans in step with concentration, with collagen synthesis rising twice as much as other proteins. Type I and III collagen mRNA rose; TGF-β mRNA did not. A control tripeptide had no significant effect.
ACL graft healing in rats
Seventy-two rats had ACL reconstruction, then weekly knee injections of saline or 0.3 or 3 mg/mL GHK-Cu for four weeks. At six weeks GHK-Cu reduced knee laxity (p = 0.009) and the lower dose made the graft stiffer (p = 0.026). By 12 weeks the differences had gone, and ultimate load, gait and histology never differed.
Bleomycin lung fibrosis in mice
Mice with bleomycin-induced lung scarring received GHK-Cu into the abdomen at 0.2, 2 or 20 µg/g on alternate days. It reduced TNF-α, IL-6 and myeloperoxidase activity in lung fluid, cut collagen deposition, rebalanced MMP-9 and TIMP-1, and partly blocked epithelial-mesenchymal transition via Nrf2, NF-κB and TGF-β1/Smad signalling.
COPD muscle loss, in patients and mice
Nine people with COPD had lower plasma GHK than 11 healthy controls (70 vs 133 ng/mL, p = 0.009), and lower levels tracked with smaller pectoral muscle. In mice exposed to cigarette smoke, GHK-Cu at 0.2 and 2 mg/kg reduced the loss of muscle mass and cross-sectional area.
Intranasal GHK-Cu in old mice (preprint)
Twenty-month-old mice given intranasal GHK-Cu at 15 mg/kg a day for two months did better on spatial memory and navigation tasks, with fewer markers of brain inflammation and axonal damage, than mice given saline. Posted on bioRxiv, a preprint server, rather than in a peer-reviewed journal.
Serum levels fall with age
GHK averages about 200 ng/mL in serum at age 20 and about 80 ng/mL by 60. The authors present the anti-inflammatory and tissue-remodelling evidence, including early mouse data on cognition, as grounds for preclinical and clinical ageing studies, not as proof of benefit.
Tissue remodelling, from its discoverer
Loren Pickart lists the remodelling processes GHK-Cu activates, from attracting repair cells to raising collagen, elastin and growth-factor production, and states that controlled studies on aged skin found tighter skin and fewer fine lines. The abstract gives no figures for those studies.
New gene data and a long list of actions
Pickart and Margolina describe every known action of GHK as apparently health-positive: blood-vessel and nerve outgrowth, more collagen, elastin and glycosaminoglycans, tissue repair in skin, lung, bone, liver and stomach lining, and anti-cancer, anti-inflammatory, anti-anxiety and DNA-repair activity. They argue that recent gene data explain the range. The abstract reports no results from treating people.
Skin regeneration and the 4,000-gene claim
Plasma, saliva and urine all contain GHK, and levels fall with age. This review from Pickart's group says GHK can raise or lower at least 4,000 human genes and lists cosmetic effects such as firmer skin and fewer wrinkles. The abstract does not say where the gene figure comes from.
Anti-wrinkle claims and the missing trials
Cell studies support GHK as an anti-wrinkle ingredient, the review concludes, but it finds a surprising absence of clinical studies of GHK-Cu or palmitoyl-GHK, and says published data on their skin permeability and effectiveness are insufficient.
Getting through the skin
GHK-Cu is fairly hydrophilic and crosses the lipid-rich outer layer of skin poorly. Liposomes might carry it further, but the review finds that how liposomes change its transport across skin has received little attention.
What people say, and what was measured
Copper peptides have fifty years of laboratory work behind them and very little in human skin. These are the claims made for GHK-Cu on product pages and in the literature that promotes it, each set against what was measured.
It rebuilds collagen and firms ageing skin.
Heard in: Journal of Biomaterials Science, The human tri-peptide GHK and tissue remodeling, by the peptide's discoverer, which states that controlled studies on aged skin found tighter skin and fewer fine lines (read October 1, 2026). Source
Collagen accumulation was measured in rats, where GHK-Cu raised collagen and other new-tissue components in step with dose. In human skin, the trial that measured outcomes objectively found nothing: after carbon dioxide laser resurfacing, computer analysis and blinded evaluators saw no faster fading of redness and no difference in wrinkles or skin quality. A 2025 review of GHK as an anti-wrinkle peptide reports a surprising absence of clinical studies. PMID: 8227353, 16847171, 39963574
Tested in people; not shownIt switches on more than 4,000 human genes, resetting skin to a younger state.
Heard in: BioMed Research International, GHK Peptide as a Natural Modulator of Multiple Cellular Pathways in Skin Regeneration, which states that GHK can raise or lower at least 4,000 human genes (read October 1, 2026). Source
The figure comes from analysing gene-activity data, by the group that discovered the peptide. It describes a signal in a database, not a change measured in anyone's skin, and a later review from the same authors lists the actions it is taken to imply. Nothing connects the number to a visible result. PMID: 26236730, 29986520
Measured, never givenBlood levels fall with age, so putting it back reverses skin ageing.
Heard in: Aging Pathobiology and Therapeutics, The potential of GHK as an anti-aging peptide, which reports serum GHK falling from about 200 ng/mL at age 20 to about 80 ng/mL by 60 (read October 1, 2026). Source
The decline with age is real and measured. Everything after it is assumption: no study has shown that a cream restores the blood level, or that restoring it changes skin. A 2025 review notes GHK-Cu crosses the outer layer of skin poorly, so how much reaches living skin from a serum is unknown. PMID: 35083444, 39795193
Measured, never givenIt heals wounds, which is what it was developed for.
Heard in: Grey Peptides listing review, October 1, 2026: listings describe GHK-Cu as a wound-healing and tissue-repair peptide. Sellers are not named.
In the trial that tested it, a 0.4% copper complex cream was compared with silver sulfadiazine and placebo in 86 patients with venous leg ulcers. Silver sulfadiazine reduced ulcer size; the copper complex did not differ from placebo. Healing has been improved in rats and in animal wound models. PMID: 1495150, 8227353, 17083573
Tested in people; not shownEach claim is quoted from where it is said, never from a seller, and checked as of October 1, 2026 against the studies listed below.
Dosing Data
There is no approved dose of GHK-Cu for any use. The table sets out what the studies actually gave, mostly creams of stated or unstated strength and injections into animals, next to the injectable range in circulation, which no trial supports.
Educational information, not medical advice. Each dose above is tagged with its source: an approved label, a published human study, animal data, or amounts reported by users. None is a recommendation for you. An unapproved compound has no established safe or effective human dose, and products sold for “research use only” are not made or tested for people. Talk to a doctor before acting on anything on this site, including before you start, stop or change any medicine or dose. Full medical disclaimer.
→ Full GHK-Cu dosage guide — the injectable ranges in circulation, set against a record with no human injection trials.
→ Blend & Stack Calculator — GHK-Cu is also sold in multi-peptide vials; the calculator shows what each draw delivers of every component; our blends and stacks hub sets out what each mix contains and what has been studied.
Side Effects & Contraindications
Reported Side Effects
The human abstracts report outcomes rather than adverse-event tables, so most of what is known comes from a single animal study and from the absence of human data.
Contraindications & Cautions
No study defines who should avoid GHK-Cu. These cautions follow from its chemistry, from the gaps above and from FDA's compounding decision.
Legal Status
GHK-Cu is not approved as a medicine in any of the jurisdictions below, but it is sold widely as a cosmetic ingredient (INCI name: copper tripeptide-1). The route decides the answer: creams and serums are one question, injections another. Status as of September 26, 2026.
Frequently Asked Questions
?Is GHK-Cu the same as the copper peptides in skin care?
Usually. "Copper peptide" on a label most often means GHK-Cu, whose INCI name is copper tripeptide-1, though other copper peptides exist, such as AHK-Cu. Everything on this page is about GHK-Cu specifically.
?Does GHK-Cu reduce wrinkles?
Cell studies suggest it could, and reviews by its discoverer say controlled studies on aged skin found tighter skin and fewer fine lines, but those abstracts give no figures. A 2025 review found a surprising absence of clinical studies, and the one randomised trial carded here, on laser-resurfaced skin, found no objective improvement over standard care.
?Has injectable GHK-Cu been tested in people?
Not in any study in our evidence set. The injection data are all from animals: rat knees, rat wound chambers and mouse abdomens. Anyone injecting it is using doses that no trial has tested.
?Can a US pharmacy compound GHK-Cu?
Not for injection: that nomination was withdrawn in April 2026. For other routes, such as creams, FDA returned GHK-Cu to Category 1 (under evaluation) on its May 14, 2026 list and plans to consult its advisory committee before the end of February 2027. Status as of September 26, 2026.
?GHK levels fall with age. Does topping them up help?
Serum GHK averages about 200 ng/mL at 20 and about 80 ng/mL by 60, and in one small study people with COPD had lower levels than healthy controls. No trial has tested whether raising GHK in people changes any outcome.
?Does GHK-Cu help hair grow?
Its discoverer's 2008 review credits it with enlarging hair follicles and improving hair-transplant success, but the abstract gives no data, and no hair study is among the papers carded here.
References
- [pubmed] Miller TR, et al. "Effects of topical copper tripeptide complex on CO2 laser-resurfaced skin." Arch Facial Plast Surg, 2006;8(4):252-9. PMID: 16847171.
- [pubmed] Bossak-Ahmad K, et al. "Ternary Cu(2+) Complexes of Human Serum Albumin and Glycyl-l-histidyl-l-lysine." Inorg Chem, 2021;60(22):16927-16931. PMID: 34730942.
- [pubmed] Lau SJ, et al. "The interaction of copper(II) and glycyl-L-histidyl-L-lysine, a growth-modulating tripeptide from plasma." Biochem J, 1981;199(3):649-56. PMID: 7340824.
- [pubmed] Maquart FX, et al. "In vivo stimulation of connective tissue accumulation by the tripeptide-copper complex glycyl-L-histidyl-L-lysine-Cu2+ in rat experimental wounds." J Clin Invest, 1993;92(5):2368-76. PMID: 8227353.
- [pubmed] Fu SC, et al. "Tripeptide-copper complex GHK-Cu (II) transiently improved healing outcome in a rat model of ACL reconstruction." J Orthop Res, 2015;33(7):1024-33. PMID: 25731775.
- [pubmed] Ma WH, et al. "Protective effects of GHK-Cu in bleomycin-induced pulmonary fibrosis via anti-oxidative stress and anti-inflammation pathways." Life Sci, 2020;241:117139. PMID: 31809714.
- [pubmed] Deng M, et al. "Glycyl-l-histidyl-l-lysine-Cu(2+) rescues cigarette smoking-induced skeletal muscle dysfunction via a sirtuin 1-dependent pathway." J Cachexia Sarcopenia Muscle, 2023;14(3):1365-1380. PMID: 36905132.
- [pubmed] Tucker M, et al. "Intranasal GHK peptide enhances resilience to cognitive decline in aging mice." bioRxiv, 2023. PMID: 38014118.
- [review] Dou Y, et al. "The potential of GHK as an anti-aging peptide." Aging Pathobiol Ther, 2020;2(1):58-61. PMID: 35083444.
- [review] Pickart L. "The human tri-peptide GHK and tissue remodeling." J Biomater Sci Polym Ed, 2008;19(8):969-88. PMID: 18644225.
- [review] Pickart L, et al. "Regenerative and Protective Actions of the GHK-Cu Peptide in the Light of the New Gene Data." Int J Mol Sci, 2018;19(7). PMID: 29986520.
- [review] Pickart L, et al. "GHK Peptide as a Natural Modulator of Multiple Cellular Pathways in Skin Regeneration." Biomed Res Int, 2015;2015:648108. PMID: 26236730.
- [review] Mortazavi SM, et al. "Topically applied GHK as an anti-wrinkle peptide: Advantages, problems and prospective." Bioimpacts, 2025;15:30071. PMID: 39963574.
- [review] Ogórek K, et al. "Are We Ready to Measure Skin Permeation of Modern Antiaging GHK-Cu Tripeptide Encapsulated in Liposomes?." Molecules, 2025;30(1). PMID: 39795193.
- [pubmed] Bishop JB, et al. "A prospective randomized evaluator-blinded trial of two potential wound healing agents for the treatment of venous stasis ulcers." J Vasc Surg, 1992;16(2):251-7. PMID: 1495150.
- [pubmed] Cangul IT, et al. "Evaluation of the effects of topical tripeptide-copper complex and zinc oxide on open-wound healing in rabbits." Vet Dermatol, 2006;17(6):417-23. PMID: 17083573.
- [pubmed] Buffoni F, et al. "Effect of tripeptide-copper complexes on the process of skin wound healing and on cultured fibroblasts." Arch Int Pharmacodyn Ther, 1995;330(3):345-60. PMID: 8836453.
- [pubmed] Abdulghani AA, et al. "Effects of topical creams containing vitamin C, a copper-binding peptide cream and melatonin compared with tretinoin on the ultrastructure of normal skin." Dis Mon, 1998;44:1-22.
Sources & Citations
Every citation on this page is PubMed-indexed and has been checked against its record, except one skin-ultrastructure study that has no PubMed record. Three References entries carry no card: a leg-ulcer trial, a rabbit wound study and a guinea-pig wound study are indexed by PubMed under glycyl-histidyl-lysine but do not name it in their titles. Grey Peptides sells nothing and links to no vendor.
Medical Disclaimer: This content is for educational and informational purposes only. It is not medical advice, and nothing here is an instruction to obtain or use any compound. Talk to a licensed clinician about your own situation.