GHK-Cu

What GHK-Cu is

GHK-Cu is a tiny peptide joined to copper. Scientists have published more than 200 papers on it since 1973. Most of that work used cells in a dish, rodents, rabbits or samples of human skin. The human studies are mainly small trials of skin care products. No large trial has tested it given to the whole body, and the FDA has not approved it as a medicine.

A peptide is a short chain of amino acids, the building blocks of protein. GHK has just three: glycine, histidine and lysine (Gly-His-Lys, or glycyl-L-histidyl-L-lysine). It grips copper ions, written Cu(II), unusually tightly. GHK-Cu is the name for the peptide with copper attached.

On its own, the peptide weighs about 340 Da. It picks up copper easily under the conditions found in the body. The copper is held mainly by a nitrogen in the ring of the histidine and by nearby nitrogens in the peptide backbone. In solution, this gives the compound a blue color.

The body makes GHK. Loren Pickart first isolated it from human plasma, the liquid part of blood, in 1973. He described it as a factor that changes cell growth and is set free when the blood protein albumin is cut up. Young adults have about 200 ng/mL in plasma. By the seventh decade of life, that has dropped to roughly one-third. Some researchers think this drop is one reason tissue regrows less well with age [1].

GHK also turns up in saliva and urine. When tissue is injured, small amounts break loose from proteins in the matrix around cells, such as SPARC/BM-40. This is why it has been proposed as one of the body’s own signals of damage and repair. It also works as a copper shuttle, carrying Cu(II) into cells and to the enzymes that need it. Many of its later effects seem to depend on that job [2].

Peer-reviewed research on GHK-Cu goes back more than five decades. It covers wound healing, rebuilding of the skin, hair, antioxidant effects and, more recently, wide effects on gene activity. A large part of it comes from companies or from groups tied to industry. This is most true of research on cosmeceuticals, which are skin care products sold with claims of a biological effect. This guide points that out where it matters.

How much research there is

GHK-Cu is one of the few research peptides with a real body of human studies. But those studies are about skin care, and they come with cautions of their own.

Question	Answer
Published studies	This guide cites 25+. The wider GHK and GHK-Cu literature runs past 200 papers, from 1973 to today
What was tested	Cells in a dish (fibroblasts, keratinocytes, hair follicles), wounds in live rodents and rabbits, human skin samples, and small skin care trials in people
People studied	Yes, mostly in small trials of skin care products on sun-aged facial skin. No large randomized trial of whole-body use
Share by type	A mix of cell, animal and human studies. Most are in cells or animals. The human share leans toward cosmetic measures
Industry or independent	A large share comes from the skin care industry and the Pickart group (Skin Biology). Independent university labs have repeated some work, but unevenly
Where the work comes from	The Pickart group wrote or co-wrote much of the research on mechanisms and gene activity. Independent wound and cytokine studies (such as Gruchlik, Hostynek, Pyo, Simeon) widen the base
How the body handles it	Passage through human skin has been measured (Hostynek). Data on whole-body handling in people are limited
Randomized controlled trials	Several small ones on cosmetic results, in skin journals. None run under drug rules for a medical use
Do the results agree	Findings on mechanisms and wounds broadly agree. The size of cosmetic effects varies with the formula and the study design

How it might work

The proposed ways GHK-Cu acts fall into three groups. One is the chemistry of how it holds copper. One is control of transcription factors, the proteins that turn genes on and off. One is direct action on enzymes and on the systems that renew the matrix around cells. All of this was worked out mainly in cells in a dish, in rodents, or in human skin samples kept alive in the lab.

Carrying copper

Copper is a trace element the body must have. More than a dozen mammal enzymes need it. They include superoxide dismutase (Cu/Zn-SOD), lysyl oxidase, cytochrome c oxidase and tyrosinase. Loose copper ions react easily and can harm cells. So the body moves copper under close guard, using carrier molecules called chaperones.

GHK is thought to be one of these chaperones. Its tight grip on Cu(II) lets it pull copper off albumin and other carriers. It then hands the copper to cells in a controlled way [2], [3].

Independent lab work on human skin samples showed that GHK-Cu gets through the stratum corneum, the tough outer layer of skin. It reached the living layers below, the epidermis and the dermis. After it was put on the surface, copper could be measured in each layer [4]. This delivery of copper through the skin seems to lie behind many of the cosmetic and wound effects credited to it.

Gene activity

The most unusual claim about GHK-Cu is how many genes it affects.

In 2015, Pickart and colleagues ran gene data for GHK through the Connectivity Map, a tool from the Broad Institute. They reported that the peptide significantly changed the activity of about 4,192 human genes. That is roughly 31.2% of the protein-coding genes in the index. Often the change pointed toward a pattern more like that of young tissue [1].

• Turned up: groups of genes for DNA repair, antioxidant defense and tissue rebuilding.
• Turned down: groups rich in genes that drive inflammation and fibrosis (scarring).

A 2018 review built on this. It read the gene data against a larger map of pathways. Its argument was that such wide gene effects explain why GHK-Cu gives steady results in injury and aging models that otherwise have little in common [5].

These analyses are exploratory. They raise ideas to test. They do not show that GHK-Cu causes any clinical result. The Connectivity Map data also come from cell lines, and those patterns may not hold in whole tissue.

TGF-β1

TGF-β1 is a master control signal for rebuilding skin. It turns fibroblasts, the cells that build connective tissue, into myofibroblasts, and it spurs them to make collagen.

One group grew normal human skin fibroblasts in a dish. GHK and its copper form raised the release of TGF-β1. The effect grew with dose, at micromolar levels, and the cells stayed just as healthy [6]. The same group also reported that GHK-Cu changed how much IL-6 fibroblasts released in response to TNF-α. Both are inflammation signals. This is one possible link between higher TGF-β and calmer local inflammation [7].

Older biochemistry work by Maquart and colleagues looked further upstream. In cultures of rat fibroblasts, GHK-Cu boosted the making of collagen and glycosaminoglycans, the sugar chains of the matrix. It did so at nanomolar levels, which are very low. That hints that it signals through a receptor and is not just a bulk supply of copper [8].

Antioxidant effects

Cu/Zn-SOD is one of the cell’s main defenses against superoxide radicals, a harmful form of oxygen. The enzyme cannot work without copper. So the idea is that GHK-Cu, by supplying usable copper, adds to the pool of working SOD. Lab studies fit this. Fibroblasts and keratinocytes (skin surface cells) treated with GHK-Cu showed more SOD activity. They also showed lower markers of lipid peroxidation, which is damage to fats [5].

The complex also acts like SOD on its own. In tests with no cells present, it broke down superoxide radicals. It has also been reported to mop up hydroxyl radicals made in Fenton-type reactions [1]. So GHK-Cu may fight oxidation in two ways at once: by helping the body’s own enzyme, and by catching radicals directly.

Enzymes that break down the matrix

Matrix metalloproteinases (MMPs) are enzymes that cut up collagen and other structural proteins. This is how the matrix around cells gets reshaped. Wounds need a balanced level of MMP activity to heal. When MMPs stay too active for too long, healing suffers and skin takes on a sun-aged look.

GHK-Cu has been reported to adjust MMPs in a way that depends on the setting. In cultures of skin fibroblasts it raised MMP-2. It also raised TIMP-1 and TIMP-2, the tissue inhibitors of metalloproteinases, which hold MMPs back [10]. In rat wounds with poor blood flow, it went with lower MMP-2 and MMP-9 [5]. Reviews describe this as control of both the enzymes and their inhibitors, which may guard against too much matrix loss [1], [5]. This MMP and TIMP balance is one of the mechanisms cited most often for GHK-Cu in skin care.

What the studies found

Most of these studies used cultured cells, wounds in rodents, or human skin samples. Where there are human trials, they usually tested how well a skin care product worked. They were not drug trials run under regulation.

Wounds

Wound research on GHK-Cu began in the 1980s. It includes surgical models in rodents, rabbits and other small animals.

• Rabbits: a tripeptide-copper complex was put on full-thickness wounds. They closed faster than wounds given the carrier alone. Under the microscope there was more granulation tissue (the new tissue that fills a wound) and more collagen [9].
• Diabetic and low-blood-flow models: several rodent studies put GHK-Cu into dressings or injected it around the wound. Skin grew back over the wound faster, and the healed skin was harder to pull apart. The authors put this down to new blood vessel growth plus matrix rebuilding [1], [5].
• Human skin in the lab: GHK-Cu raised VEGF, a growth signal for blood vessels. It also shifted blood vessel markers in a way that fits early wound repair [5].

Overall, the animal and cell data on wounds agree fairly well from one species and injury type to the next. Few studies have compared GHK-Cu directly with standard wound care compounds.

Skin and cosmetics

Most of the human data on GHK-Cu comes from skin care research. These studies tend to be small, paid for by industry, and aimed at sun-aged skin on the face.

• Fibroblasts: Maquart and colleagues showed in a dish that GHK-Cu made fibroblasts produce more collagen [8]. This effect is the core of its use in anti-wrinkle products. Simeon and colleagues, in the same lab, later found that it also raised MMP-2 and the TIMPs in skin fibroblasts, so it takes part in reshaping matrix as well as building it [10].
• Skin stem cells: a 2012 study in the Journal of Peptide Science used lab-grown models of human skin. GHK without copper helped markers of epidermal stem cells recover. That suggests it does more than deliver copper [11].
• Sun-aged facial skin: in small groups of people, clinical-grade formulas with GHK-Cu were put on the skin for 12 to 16 weeks. Graders reported better scores for skin looseness, clarity and fine wrinkles. Most of these studies are in dermatology and cosmetic science journals. Critics have pointed to industry funding and limited blinding [1].
• Getting through skin: Hostynek and colleagues measured how much GHK-Cu passes into human skin in the lab. The complex carried measurable copper into the living epidermis and dermis. This backs the skin care use at the level of how the compound moves through tissue [4].

Hair

GHK-Cu and related tripeptide-copper complexes have drawn interest for their effects on hair.

• Human follicles in culture: Pyo and colleagues grew human scalp hair follicles in the lab. A tripeptide-copper complex made anagen, the growth phase, last longer. The dermal papillae, the small structures at the base of each follicle, got bigger [12].
• Follicle cells: in related lab work, GHK-Cu made two cell types multiply: dermal papilla cells and keratinocytes of the outer root sheath. Both matter for the hair cycle.

Human data on hair growth are limited. Most come from small open-label cosmetic trials, where everyone knows what is being used. Few come from randomized, placebo-controlled dermatology studies.

Inflammation

These effects have been described in cells and in tissue.

• Cytokines: fibroblasts in culture were stimulated with TNF-α. GHK-Cu lowered their release of IL-6. The effect is thought to involve a damping of the NF-κB pathway, downstream of enzymes called kinases that respond to copper [7].
• TGF-β1: GHK-Cu raises TGF-β1 at the same time. TGF-β helps shut down short-term inflammation, so this may help inflammation resolve [6].
• Reactive oxygen: by acting like SOD and by catching radicals directly, GHK-Cu limited inflammation from oxidation in cultures of fibroblasts and keratinocytes [1].

Brain and nerves

Interest in GHK-Cu and the nervous system is fairly new. It has centered on gene effects tied to loss of thinking ability with age.

• Nervous system genes: in a 2017 analysis, Pickart and colleagues again used Broad Connectivity Map data. They reported that GHK changed the activity of many genes that matter for the nervous system. These included genes for upkeep of synapses, for nerve growth signals and for pathways of nerve cell loss [13].
• Outer nerves: other discussion has looked at whether GHK might help repair peripheral nerves, and whether it changes how astrocytes, a type of support cell in the brain, react to injury. Few experiments have been run that test this directly [5].

No clinical study of adequate size supports a claim that GHK-Cu directly helps thinking or slows nerve disease. The findings so far are ideas to test.

Cancer

The cancer research on GHK-Cu is small and mixed. It needs careful reading. GHK-Cu helps blood vessels grow and tissue repair itself. Tumors also rely on new blood vessels. So in theory there is a concern where a cancer is active. At the same time, gene and cell studies have reported effects that depend on the setting.

• Gene data: Pickart’s 2015 Connectivity Map analysis found that GHK turned down a number of genes that are overactive in aggressive human cancers. It also turned up pathways close to tumor suppressors. This led to the suggestion of a protective pattern that depends on context [1].
• The blood vessel caution: even so, GHK-Cu’s effect on blood vessel growth is well established. That calls for caution in research that involves existing tumors. No clinical evidence shows that GHK-Cu is safe or helpful in cancer.

In short, GHK-Cu’s place in cancer research is limited to talk of mechanisms and gene activity. No controlled clinical evidence supports its use to prevent cancer, to treat it or as an add-on therapy.

Safety

In animals and cells

• Rodents in wound and skin studies generally tolerated the doses tested. No signs of acute toxicity appeared at typical research doses.
• Published peer-reviewed studies report no evidence of gene damage or cancer at the levels found in the body.
• In cell cultures, it harmed cells only at levels far above those found in the body. Those levels are usually well above what skin care or wound uses involve.

In people

• GHK-Cu has been used on the skin in cosmeceuticals for a long time. Most reported side effects were mild, short-lived redness or irritation at the spot.
• Small clinical trials of skin care products have not consistently reported any serious side effects.
• There is no solid human safety data for injected GHK-Cu. How it behaves in the whole body is poorly understood, and results from skin use do not carry over.

What is not known

• Active cancer. It helps blood vessels and tissue grow. In theory that is a concern for patients or research subjects with an active or recent cancer. This has not been studied well enough.
• Copper load. Repeated whole-body doses could, in principle, affect the body’s copper balance. No adequate human data address this.
• Drug interactions. These have not been formally worked out. Based on mechanism, interactions are plausible with copper chelators (drugs that bind copper), with drugs that block blood vessel growth, and with drugs that alter the immune system.
• Quality. Research-grade GHK-Cu differs a great deal from one supplier to the next. Checking by HPLC, a lab purity test, and review of the certificate of analysis (CoA) matter for keeping batches alike.

Legal status in the US

• Not FDA approved. GHK-Cu has no approval as a medicine from the FDA. The same is true of the EMA in Europe and the MHRA in the UK.
• Used in cosmetics. GHK-Cu and its derivatives appear in cosmetic products under several ingredient (INCI) names, such as Copper Tripeptide-1.
• Sport. GHK-Cu is not named on the current Prohibited List of the World Anti-Doping Agency (WADA). But peptides that grow blood vessels and repair tissue can fall under the broader S0 class, non-approved substances.
• Research use. Outside cosmetics, it is supplied as a reagent for in vitro and laboratory research.

Limits of the research

1. Mostly animals and cells. Much of the work on mechanisms rests on rodent wounds and on human fibroblasts or keratinocytes grown in a dish. It is not certain these results carry over to the whole human body, above all for whole-body use.
2. Small human trials. The human data come largely from skin care trials. These had modest numbers of people and uneven blinding. They measured results on clinical grading scales, not through tissue samples or biomarkers.
3. Industry and academia. Companies in the skin care business produced or paid for a meaningful share of the research. Many of these studies use sound methods. Still, funding is something to weigh when reading claims of benefit, most of all for sun-aged skin.
4. Reading the Connectivity Map. The figure of 4,192 genes, or 31.2% of the genome, is striking. But it comes from computer analysis of gene patterns in cell lines. It does not show a cause-and-effect change in living people. It is an idea to test.
5. Gaps in how the body handles it. Apart from passage through the skin, human data on whole-body handling of GHK-Cu are sparse. How a dose translates from one route or species to another is still uncertain.
6. The formula matters. GHK-Cu’s activity is sensitive to the formula, to the ratio of copper to peptide, and to breakdown in storage. Studies do not always report these details, so comparing one study with another is hard.

GHK-Cu has decades of cell, animal and skin care research behind it. What it has not had is a large, independent human trial.

References

Selected peer-reviewed references. Ordered roughly by date of publication. DOIs and PMIDs provided for independent verification.

1. Pickart L, Vasquez-Soltero JM, Margolina A (2015). GHK Peptide as a Natural Modulator of Multiple Cellular Pathways in Skin Regeneration. BioMed Research International, 2015, 648108. DOI: 10.1155/2015/648108. PMID: 26236730
2. Pickart L, Thaler MM (1973). Tripeptide in human serum which prolongs survival of normal liver cells and stimulates growth in neoplastic liver. Nature New Biology, 243(124), 85–87. PMID: 4349668
3. Pickart L, Vasquez-Soltero JM, Margolina A (2012). The human tripeptide GHK-Cu in prevention of oxidative stress and degenerative conditions of aging: implications for cognitive health. Oxidative Medicine and Cellular Longevity, 2012, 324832. DOI: 10.1155/2012/324832. PMID: 22666519
4. Hostynek JJ, Dreher F, Maibach HI (2011). Human skin penetration of a copper tripeptide in vitro as a function of skin layer. Inflammation Research, 60(1), 79–86. PMID: 20721598
5. Pickart L, Margolina A (2018). Regenerative and Protective Actions of the GHK-Cu Peptide in the Light of the New Gene Data. International Journal of Molecular Sciences, 19(7), 1987. DOI: 10.3390/ijms19071987. PMID: 29986520
6. Gruchlik A, Chodurek E, Dzierzewicz Z (2014). Effect of GLY-HIS-LYS and its copper complex on TGF-β1 secretion in normal human dermal fibroblasts. Acta Poloniae Pharmaceutica, 71(6), 954–958. PMID: 25745767
7. Gruchlik A, Jurzak M, Chodurek E, Dzierzewicz Z (2012). Effect of Gly-Gly-His, Gly-His-Lys and their copper complexes on TNF-α-dependent IL-6 secretion in normal human dermal fibroblasts. Acta Poloniae Pharmaceutica, 69(6), 1303–1306. PMID: 23285694
8. Maquart FX, Pickart L, Laurent M, et al. (1988). Stimulation of collagen synthesis in fibroblast cultures by the tripeptide-copper complex glycyl-L-histidyl-L-lysine-Cu²⁺. FEBS Letters, 238(2), 343–346. PMID: 3169264
9. Gul NY, Topal A, Cangul IT, Yanik K (2008). The effects of topical tripeptide copper complex and helium-neon laser on wound healing in rabbits. Veterinary Dermatology, 19(1), 7–14. PMID: 18177285
10. Siméon A, Emonard H, Hornebeck W, Maquart FX (2000). The tripeptide-copper complex glycyl-L-histidyl-L-lysine-Cu²⁺ stimulates matrix metalloproteinase-2 expression by fibroblast cultures. Life Sciences, 67(18), 2257–2265. PMID: 11045606
11. Choi HR, Kang YA, Ryoo SJ, Shin JW, Na JI, Huh CH, Park KC (2012). Stem cell recovering effect of copper-free GHK in skin. Journal of Peptide Science, 18(11), 685–690. PMID: 23019153
12. Pyo HK, Yoo HG, Won CH, Lee SH, Kang YJ, Eun HC, Cho KH, Kim KH (2007). The effect of tripeptide-copper complex on human hair growth in vitro. Archives of Pharmacal Research, 30(7), 834–839. PMID: 17703734
13. Pickart L, Vasquez-Soltero JM, Margolina A (2017). The Effect of the Human Peptide GHK on Gene Expression Relevant to Nervous System Function and Cognitive Decline. Brain Sciences, 7(2), 20. DOI: 10.3390/brainsci7020020. PMID: 28212278
14. Pickart L, Margolina A (2018). The Effect of the Human Peptide GHK on Gene Expression Relevant to Regeneration and Lung Biology. International Journal of Molecular Sciences, 19(7), 1987.
15. Maquart FX, Bellon G, Chaqour B, et al. (1993). In vivo stimulation of connective tissue accumulation by the tripeptide-copper complex glycyl-L-histidyl-L-lysine-Cu²⁺ in rat experimental wounds. Journal of Clinical Investigation, 92(5), 2368–2376. DOI: 10.1172/JCI116842. PMID: 8227353
16. Maquart FX, Siméon A, Pasco S, Monboisse JC (1999). Regulation of cell activity by the extracellular matrix: the concept of matrikines. Journal de la Société de Biologie, 193(4–5), 423–428. PMID: 10673008
17. Pickart L, Vasquez-Soltero JM, Margolina A (2014). GHK and DNA: resetting the human genome to health. BioMed Research International, 2014, 151479. DOI: 10.1155/2014/151479. PMID: 25202709
18. Pickart L, Vasquez-Soltero JM, Pickart FD, Majnarich J (2015). GHK, the human skin remodeling peptide, induces anti-cancer expression of numerous caspase, growth regulatory, and DNA repair genes. Journal of Analytical Oncology, 4(2), 79–87.
19. Pickart L, Vasquez-Soltero JM, Margolina A (2012). The human tripeptide GHK (glycyl-L-histidyl-L-lysine), the copper switch, and the treatment of the degenerative conditions of aging. In: Anti-Aging Therapeutics, Vol. XV, American Academy of Anti-Aging Medicine, 301–312.
20. Beretta G, Artali R, Caneva E, Facino RM (2008). Conformational analysis of the tripeptide Gly-His-Lys (GHK) self-aggregates by MALDI-MS, ESI-MS and molecular modelling. Implications for their mechanism of action in wound healing. Journal of Pharmaceutical and Biomedical Analysis, 47(4–5), 875–881. PMID: 18468827
21. Miller DM, DeSilva D, Pickart L, Aust SD (1990). Effects of glycyl-histidyl-lysyl chelated Cu(II) on ferritin dependent lipid peroxidation. Advances in Experimental Medicine and Biology, 264, 79–84. PMID: 2244554
22. Beretta G, Arlandini E, Artali R, Anton JM, Maffei Facino R (2008). Acrolein sequestering ability of the endogenous tripeptide glycyl-histidyl-lysine (GHK): characterization of conjugation products by ESI-MSn and theoretical calculations. Journal of Pharmaceutical and Biomedical Analysis, 47(3), 596–602. PMID: 18424046
23. Pickart L (2008). The human tri-peptide GHK and tissue remodeling. Journal of Biomaterials Science, Polymer Edition, 19(8), 969–988. PMID: 18644225
24. Trumbo P, Yates AA, Schlicker S, Poos M (2001). Dietary reference intakes: vitamin A, vitamin K, arsenic, boron, chromium, copper, iodine, iron, manganese, molybdenum, nickel, silicon, vanadium, and zinc. Journal of the American Dietetic Association, 101(3), 294–301. PMID: 11269606 [background copper biology]
25. Schlesinger DH, Pickart L, Thaler MM (1977). Growth-modulating serum tripeptide is glycyl-histidyl-lysine. Experientia, 33(3), 324–325. PMID: 852459
26. Arul V, Gopinath D, Gomathi K, Jayasree R, Jayakumar R (2005). Copper-tripeptide (GHK-Cu) as a wound healing agent: in vivo evaluation in a rat model. Journal of Biomedical Materials Research Part B: Applied Biomaterials, 73(2), 383–391. PMID: 15654713