GHK-Cu

GHK is a tripeptide made of glycine, histidine and lysine. In 1973 Loren Pickart and M. M. Thaler reported a tripeptide in human serum that prolonged the survival of normal liver cells and stimulated the growth of liver tumour cells in culture ^[1]. In 1980 Pickart and colleagues reported in Nature that the peptide co-purified with roughly equal amounts of copper, readily formed a complex with copper(II) ions and increased copper uptake into cultured cells, which led them to propose that it acts as a copper carrier ^[2]. The copper-bound form is known as GHK-Cu.

GHK-Cu is sold in two quite different markets. As a cosmetic ingredient, listed under the name copper tripeptide-1, it appears in creams and serums. As a “research peptide”, it is sold in vials for injection, which is the use regulators have raised concerns about ^[14]. The evidence for these two uses is different, and this page separates them.

It is sometimes grouped with other peptides marketed for repair or appearance, such as BPC-157 and TB-500, but it is chemically unrelated to both. For how the research peptide market works in general, see what research peptides are.

The most studied mechanism is an effect on the connective-tissue matrix. In a 1988 study using fibroblast cultures, GHK-Cu stimulated collagen synthesis starting at concentrations between 10⁻¹² and 10⁻¹¹ M, with a maximum at 10⁻⁹ M, independent of any change in cell number. The authors noted that the GHK sequence occurs within type I collagen and suggested it may be released at wound sites ^[3].

A second line of work uses gene-expression data. In a 2012 study of lung tissue from smokers with COPD, researchers used the Connectivity Map database to identify GHK as a compound whose gene-expression effects ran opposite to the signature of emphysema. In the laboratory, GHK applied to lung fibroblasts from people with COPD restored their ability to contract and remodel collagen ^[9]. Pickart and a co-author later reviewed such gene data and argued that GHK regulates many pathways involved in repair and protection ^[10]; this review is by the peptide’s discoverer and is a summary of largely preclinical findings rather than new clinical evidence.

In a 2003 veterinary surgery study, 24 rats had full-thickness wounds created in an area with deliberately reduced blood supply. Wounds treated daily with a 2% GHK-Cu gel shrank by 64.5% of their starting area by day 13, compared with 45.6% for the gel base alone and 28.2% for untreated wounds, and had lower levels of the inflammatory marker TNF-alpha and of the tissue-degrading enzymes MMP-2 and MMP-9 ^[4].

Not all animal results are positive. A 2013 study of skin flaps in rats that had previously received radiation found that twice-daily GHK-Cu gel made no difference to flap ischaemia, blood-vessel number or area, or VEGF expression compared with a control ointment ^[5].

Most of the popular interest in GHK-Cu relates to skin ageing. A 2025 review of topical GHK as an anti-wrinkle ingredient concluded that cell studies support its effect on collagen and glycosaminoglycan production, but it described “a surprising absence of clinical studies” of GHK-Cu and its palmitoylated form, and noted that getting a water-loving peptide through the skin is a practical challenge ^[11].

A 2026 systematic review in Aesthetic Surgery Journal found 20 eligible studies of GHK-Cu used alone for aesthetic purposes, of which 18 were preclinical and only two were randomised controlled trials. It judged that GHK-Cu has a reasonable biological basis but that the clinical evidence was limited by small numbers and inconsistent methods ^[12].

For hair, the one controlled human trial we found did not test GHK-Cu alone. In a 2016 Korean study, 45 men with pattern hair loss applied a complex of 5-aminolevulinic acid and GHK peptide (at two strengths) or placebo daily for six months. Both active groups had larger increases in hair count than placebo, with no difference in hair length or thickness and no adverse events reported ^[8]. Because the product combined two substances, the result cannot be attributed to GHK alone.

The main clinical study of GHK-Cu is a 1994 multicentre, randomised, evaluator-blinded, placebo-controlled trial in people with diabetic foot ulcers, all of whom also received standardised wound care. Daily topical GHK-Cu gel increased median closure of plantar ulcers to 98.5%, compared with 60.8% for the gel base, and the difference was larger in ulcers bigger than 100 mm². Ulcer infections were also less common in the treated group (7% versus 34%) ^[6]. GHK-Cu has not become an approved treatment for diabetic ulcers.

In a 2006 randomised study, 13 patients who had carbon dioxide laser resurfacing around the mouth used skin-care products with or without GHK-Cu. Blinded assessment and computer analysis found no significant difference in redness, wrinkles or overall skin quality between groups, although patients using the GHK-Cu products reported higher satisfaction ^[7].

We found no published human trial of injected GHK-Cu. A 2026 Sports Medicine review of peptides marketed directly to patients, which included GHK-Cu, concluded that rigorous human safety data for such unapproved peptides are scarce ^[13].

Cell culture: collagen synthesis in fibroblasts responded from about 10⁻¹² M, with a maximum effect at 10⁻⁹ M ^[3]. Animal: the 2003 rat wound study applied a 2% GHK-Cu gel once daily for 13 days ^[4]; the 2013 irradiated-flap study applied GHK-Cu gel twice daily for 10 days ^[5].

Human: the diabetic ulcer trial used a daily metered application of topical GHK-Cu gel ^[6], and the laser-resurfacing study used GHK-Cu skin-care products ^[7]; the abstracts do not give a single standard concentration. No human dose for injected GHK-Cu has been established in any published trial, and none of these figures is a recommendation. The peptide calculator can convert vial contents to concentrations but does not indicate an appropriate amount.

In the published topical studies, GHK-Cu was generally well tolerated; the hair study reported no adverse events ^[8], and the diabetic ulcer trial reported fewer infections in the treated group than with the gel base ^[6]. These trials were small and short.

Injection is a different matter. The FDA has said that compounded injectable drugs containing GHK-Cu may pose a risk of immune reactions (immunogenicity) because of aggregation and peptide-related impurities, and that human safety data are limited ^[14]. The original 1973 report also noted that the serum tripeptide stimulated the growth of liver tumour cells in culture ^[1]; the relevance of this to people is unknown, but it is one reason reviewers call for proper safety studies.

GHK-Cu is not approved as a medicine by the FDA, the UK’s MHRA or, as far as we are aware, any other regulator. It is widely used in cosmetics under the ingredient name copper tripeptide-1, which covers topical skin-care use only.

In the US, the FDA previously placed “GHK-Cu (for injectable routes of administration)” in category 2 of its interim compounding policy, the list of bulk substances that may present significant safety risks; the nomination was later withdrawn and the FDA now lists it among substances previously in category 2 ^[14]. GHK-Cu was not among the peptides considered at the FDA’s July 2026 compounding advisory committee meeting. For national rules on research peptides, see our legal status overview and the UK page.

Research-grade GHK-Cu is supplied as a powder in sealed vials. Peptides are generally stored cold, dry and away from light, and reconstituted solutions are refrigerated and used within a limited period. Our guide to storing peptides covers the general principles.

Research GHK-Cu is not regulated like a medicine, so batch testing is the main safeguard. Compare prices, read how to read a COA, and see which vendors publish third-party tested results.