GHK-Cu Serums and Creams

How is GHK-Cu written on a cosmetic label?

In the ingredient lists of cosmetic products, GHK-Cu appears under the international nomenclature of cosmetic ingredients (INCI) as “Copper Tripeptide-1.” The European Commission’s CosIng database defines this ingredient as “the copper complex of Tripeptide-1” and lists its function as “skin conditioning.” ^[7] CosIng is an information database; an ingredient’s presence there does not mean safety approval or evidence of efficacy. The database also contains other copper-peptide derivatives with similar names; these are not the same substance as GHK-Cu and do not have the same evidence. ^[2]

In Türkiye, the Cosmetic Products Regulation defines a cosmetic product as a product applied to the external parts of the body (skin, scalp hair, hair, nails, lips, external genital organs) or to the teeth and oral mucosa, whose main purpose is to clean, protect, change the appearance of or keep these parts in good condition. ^[8] Serums and creams fall within this definition; GHK-Cu used by injection does not. The evidence and regulatory status of injectable use are covered on the main page.

Which concentrations were used in studies?

Concentration information is one of the weakest links in human studies of GHK-Cu.

• Eyebrow serum (2%): In a randomized, double-blind, vehicle-controlled split-face study with 18 healthy participants, a serum containing a nominal 2% GHK-Cu increased hair count and hair thickness on the treated side over 12 weeks; no serious adverse events were reported. The 2026 pharmaceutical review evaluates this study as the strongest recent controlled cosmetic signal, but notes that it is single-center, small and that the chemical state of the test material was not defined. ^[2]
• Face and eye-area creams: The 12-week studies with 71 and 41 women are reported in the reviews of the researcher who discovered the molecule as a 2002 conference abstract or report; the review does not state the GHK-Cu concentration of the creams. ^[5]
• Care after laser: In the randomized study, skin care products containing GHK-Cu were used; the concentration is not given in the publication’s abstract. ^[4]

The pharmaceutical review states that in none of these human studies were basic properties such as the proportion of copper actually bound to the peptide, the amount of free copper or the level of active substance in the skin reported. ^[2] A percentage on a product label is therefore not information comparable with the product used in the studies, and no useful concentration range has been defined.

Does GHK-Cu penetrate the skin?

This question is the precondition for a cosmetic effect. In a preformulation study, the distribution coefficient (log D) of GHK-Cu was found to be between −2.38 and −2.49 in the pH 4.5–7.4 range, that is, the molecule is highly water-soluble (hydrophilic) rather than fat-soluble. ^[3] An independent review states that this hydrophilic structure makes passage through the skin barrier difficult, and that forming a metal complex and chemically modifying with a hydrophobic group increase penetration. The same review adds that measuring GHK-Cu penetration into the skin is also hard because copper within the skin can be exchanged with other binders. ^[1]

Microneedle application markedly increased uptake of GHK-Cu into the skin in laboratory and pig skin models; however, according to the 2026 systematic review, this approach has not yet been tested in a single registered and adequately powered randomized human study. ^[6]

How stable is it in a formulation?

The most concrete data on the stability of GHK-Cu within a product come from a preformulation study done in New Zealand: ^[3]

• The peptide remained stable for at least two weeks at 60 °C in water and in pH 4.5–7.4 buffers.
• It broke down by hydrolysis under basic and oxidizing conditions and, to a lesser extent, under acidic conditions; one of the degradation products was histidine.
• It was compatible with a particular lipid carrier system (Span 60-based niosomes); it was less stable in the presence of a negatively charged lipid (dicetyl phosphate).

Reporting the same study, the independent review states that the oxidizing environment was the most challenging condition and that after one hour only 84.2% of the peptide remained in it. ^[1]

The 2026 pharmaceutical review, on the other hand, stresses that stability is not limited to the breakdown of the peptide: the structure of the copper-GHK bond varies with pH and other binders in the medium; chelators, citrate, phosphate, proteins and some excipients can transfer copper from the peptide to other components, and reducing agents and antioxidants can change the copper’s valence balance. The authors therefore recommend screening excipients for their copper-binding and redox effects. ^[2] These recommendations are aimed at formulation developers; they are not studies measuring the skin result of a particular combination of skin care products.

Which skin outcomes were measured in studies?

The table shows that the randomized post-laser study that objectively measured wrinkles and skin quality found no difference, while the favorable results mostly come from reports whose details cannot be examined independently or from studies reported in the review by the researcher who discovered the molecule.

How should the quality of the evidence be judged?

Three independent reviews reach a similar conclusion:

• Despite its widespread use in anti-wrinkle products, clinical studies conducted with GHK-Cu are surprisingly few. ^[1]
• The human literature is thin and scattered; most randomized studies are small and were done with face creams. About 35% of the primary GHK-Cu literature in the review period includes as author the researcher who first isolated the molecule or a colleague from a skin care company. ^[6]
• Historical cosmetic reports are small or poorly defined; until controlled clinical efficacy is shown, GHK-Cu should be viewed as a promising but unproven substance. ^[2]

This picture keeps the evidence for signs of aging in facial skin at the level of “small, mostly unpublished and industry-linked studies” (D), and for post-laser healing at “no benefit shown” (E).

Are serums and creams safe?

No serious side effects have been reported in small studies; no serious adverse event was seen in the eyebrow serum study. ^[2] However, there is no systematic safety study. The pharmaceutical review states that copper is a known contact allergen in susceptible people and that carriers that increase absorption or a compromised skin barrier increase immunologically meaningful exposure; the same review writes that occlusive application may increase hydration and penetration but may also increase irritation. ^[2]

Cosmetic products are defined not for treating disease but for maintaining the appearance and condition of the skin. ^[8] When skin disease, an open wound or care after a procedure such as laser is involved, product choice rests on the assessment of the physician performing the procedure.

Limits of this page

This page summarizes the published studies on skin care products containing GHK-Cu. It does not recommend a brand, product, concentration or frequency of use; it does not verify claims on product labels. GHK-Cu used by injection is a different subject and is covered on the main page.