The published research on GHK-Cu shows a consistent signal in cell culture and animal wound models, mixed results in human wound trials, and a small set of topical cosmetic studies, several of which we could not find as full, indexed reports. GHK-Cu is not an FDA-approved drug, and the human studies we found all applied it to the skin.
That is a stronger record than most peptides sold for research can show, and a narrower one than the claims usually attached to it. This review goes layer by layer.
What it is
GHK is a tripeptide, three amino acids in a row: glycine, histidine and lysine. It binds copper(II) ions, and the complex of the two is written GHK-Cu. Our review of the skin peptides places it in the wider class.
Discovery
The peptide was first reported by Loren Pickart and M. M. Thaler in 1973 (Nature New Biology), in a paper describing a tripeptide in human serum that prolonged the survival of normal liver cells. The copper connection followed in 1980, when Pickart and colleagues reported in Nature that the tripeptide co-isolated with roughly equal amounts of copper, readily formed complexes with copper(II), and increased uptake of the metal into cultured liver tumor cells. They proposed that it might act as a copper transport factor.
Pickart's later reviews state that the plasma level of GHK is about 200 nanograms per milliliter at age 20 and falls to about 80 by age 60. That figure is widely repeated. It describes a measured concentration, and it is not evidence that restoring the level changes anything.
What cell studies report
The founding cell result for skin is from Maquart and colleagues (FEBS Letters, 1988), who reported that GHK-Cu stimulated collagen synthesis in cultured fibroblasts at very low concentrations, without changing cell number. They also pointed out that the sequence GHK occurs within a chain of type I collagen, and suggested the tripeptide might be released where tissue is broken down.
A more recent finding came from outside the original research circle and from an unexpected direction. Campbell and colleagues (Genome Medicine, 2012) profiled gene expression in lung tissue from smokers with emphysema, then searched a public database of drug-induced gene signatures for compounds that produced the opposite pattern. GHK came up. In the lab, they reported that GHK restored the ability of fibroblasts taken from diseased lungs to contract and remodel collagen. That is a cell-culture result, and the authors called for further study.
What animal studies report
Maquart and colleagues (Journal of Clinical Investigation, 1993) placed wire-mesh wound chambers under the skin of rats and delivered GHK-Cu into them. Compared with saline, they reported concentration-dependent increases in protein, collagen and glycosaminoglycans inside the chambers, while a control tripeptide had no significant effect. The same group later reported changes in specific matrix components in the same model (Siméon and colleagues, Journal of Investigative Dermatology, 2000).
In a topical model, Canapp and colleagues (Veterinary Surgery, 2003) created open wounds in skin with reduced blood supply in 24 rats. By day 13, wound area had decreased by 64.5 percent with a GHK-Cu gel, 45.6 percent with the gel vehicle alone and 28.2 percent with no treatment.
What human wound trials report
Two controlled trials in patients point in different directions.
Mulder and colleagues (Wound Repair and Regeneration, 1994) ran a multicenter, randomized, evaluator-blinded, placebo-controlled study of a GHK-Cu gel on diabetic foot ulcers, alongside standardized wound care. They reported a median 98.5 percent closure of plantar ulcers with the gel against 60.8 percent with the vehicle, and fewer infections.
Bishop and colleagues (Journal of Vascular Surgery, 1992) ran a randomized, evaluator-blinded trial in venous leg ulcers, with 86 patients completing it. A cream containing a tripeptide copper complex did no better than placebo. The comparison treatment, silver sulfadiazine, reduced ulcer size significantly more than either.
We found no FDA-approved drug that came out of this work.
What human cosmetic studies report
This is the evidence most marketing leans on, and it is the thinnest to check. A 2015 review by Pickart and colleagues (BioMed Research International) summarizes four studies:
- A facial cream used by 71 women with photoaged skin for 12 weeks, with reported improvements in skin laxity, clarity and appearance and increased skin density and thickness (Leyden and colleagues, 2002).
- An eye cream used by 41 women for 12 weeks, reported to outperform a placebo and a vitamin K cream (Leyden and colleagues, 2002).
- A cream used by 67 women aged 50 to 59 for 12 weeks, with similar reported improvements (2005).
- A one-month comparison on thigh skin in which collagen production was reported to rise in 70 percent of those using GHK-Cu, against 50 percent with vitamin C and 40 percent with retinoic acid (Abdulghani and colleagues, 1998).
We could not locate these four as indexed full reports in PubMed, so the details above are as the review describes them. The endpoints are measures of appearance and skin structure, over 12 weeks or less.
One cosmetic trial that is indexed gives a more modest picture. Miller and colleagues (Archives of Facial Plastic Surgery, 2006) randomized patients who had undergone laser skin resurfacing to aftercare with or without GHK-Cu products. Thirteen completed the study. Blinded evaluators and computer analysis found no significant difference in redness, wrinkles or overall skin quality. Patients using GHK-Cu rated their own improvement higher.
On whether the complex gets into skin at all, Hostynek and colleagues (Inflammation Research, 2010) applied it to human skin in a laboratory diffusion cell and reported that copper passed through and was retained in the tissue over 48 hours. That is a penetration measurement on donated skin, not a clinical result.
Regulatory status
GHK-Cu is not approved by the FDA as a drug for any use. It appears in cosmetic products, and the FDA does not approve cosmetic products or ingredients, other than color additives, before they go on sale.
In compounding policy, the FDA's nominated-substance list, as updated on May 14, 2026, lists "GHK-Cu (except for injectable routes of administration)" in Category 1, the category for substances under evaluation. The nomination for injectable routes was withdrawn, and the agency's safety summary for that use cites a potential immune reaction risk from aggregation and impurities and says human safety data are limited. The FDA has said it intends to consult its Pharmacy Compounding Advisory Committee on GHK-Cu before the end of February 2027. None of this is an approval.
The limits, plainly
- Route. The human studies we found are topical. Findings on skin do not transfer to any other route.
- Endpoint. The cosmetic studies measure appearance over weeks. The wound trials conflict.
- Size and publication. The cosmetic studies involve dozens of participants, and several are known mainly through review articles.
- Formulation. The copper complex, not the bare peptide, is the thing studied. Our review of the skin peptides explains why that matters for this compound.
Frequently asked questions
What is GHK-Cu?
A complex of the tripeptide glycyl-histidyl-lysine with copper. The peptide was first reported in human serum in 1973.
Is GHK-Cu FDA-approved?
No. It is used as a cosmetic ingredient, which does not require FDA approval, and it is under evaluation for pharmacy compounding by some routes. Neither is a drug approval.
Has GHK-Cu been tested in humans?
Yes, on the skin: in two wound trials with conflicting results and in several small cosmetic studies. We found no published human trial by any other route.
Who discovered GHK-Cu?
Loren Pickart, who reported the tripeptide in 1973 and its copper binding in 1980.
Does research on topical GHK-Cu apply to other forms?
No. Results from one route of exposure and one formulation do not carry over to another.
Sources:
- Pickart and Thaler, Nat New Biol, 1973 (tripeptide in human serum, liver cells)
- Pickart et al., Nature, 1980 (copper binding and uptake, cultured hepatoma cells)
- Maquart et al., FEBS Lett, 1988 (collagen synthesis, fibroblast cultures)
- Campbell et al., Genome Med, 2012 (emphysema gene signature, human lung fibroblasts)
- Maquart et al., J Clin Invest, 1993 (rat wound chambers)
- Siméon et al., J Invest Dermatol, 2000 (rat wound chambers, matrix components)
- Canapp et al., Vet Surg, 2003 (topical gel, ischemic wounds in 24 rats)
- Mulder et al., Wound Repair Regen, 1994 (randomized trial, diabetic ulcers)
- Bishop et al., J Vasc Surg, 1992 (randomized trial, venous ulcers, 86 patients)
- Pickart, Vasquez-Soltero and Margolina, Biomed Res Int, 2015 (review, including the cosmetic studies)
- Pickart and Margolina, Int J Mol Sci, 2018 (review)
- Miller et al., Arch Facial Plast Surg, 2006 (randomized, laser-resurfaced skin, 13 patients)
- Hostynek et al., Inflamm Res, 2010 (human skin penetration in vitro)
- FDA, Bulk Drug Substances Nominated for Use in Compounding Under Section 503A (category list, updated May 14, 2026)
- FDA, Certain bulk drug substances for use in compounding that may present significant safety risks
- FDA, FDA Authority Over Cosmetics: How Cosmetics Are Not FDA-Approved, but Are FDA-Regulated
No compound discussed in this review is FDA-approved. Nothing above is dosing guidance or a treatment claim. Research use only.
For research use only · Not for human or veterinary use · No research compound discussed here is FDA-approved for any indication