GHK-Cu in the UK: the copper peptide with evidence on skin and none injected

01The short version

GHK-Cu is a copper-binding tripeptide (glycyl-histidyl-lysine) that occurs naturally in blood and declines with age. It is best known in skincare, where topical GHK-Cu has decent evidence for collagen and skin repair, and is increasingly sold in the UK as an injectable research peptide, where it has almost none. Legal, unlicensed, and not something COGENT makes.

02What it is

A three-amino-acid peptide that binds copper. Discovered in 1973 in human plasma, it signals for wound healing, collagen and elastin synthesis, and antioxidant enzyme production. Blood levels fall steeply between 20 and 60, which is the basis of the anti-ageing marketing.

03Topical GHK-Cu: the part with evidence

Several small human trials of copper peptide creams and serums report improved skin thickness, firmness, fine lines and wound healing. The effect sizes are modest and the studies are often industry-funded, but the direction is consistent and the risk is low. This is the form sold in UK skincare, and at that use it is a cosmetic, freely available, and reasonable.

04Injectable GHK-Cu: the part without

Vials of GHK-Cu for subcutaneous injection are sold as research peptides in the UK on the strength of the topical data and animal work. There are no human trials of injected GHK-Cu for anything. Claims about hair growth, systemic anti-ageing and "resetting gene expression" come from cell-culture studies. The blue solution is copper, which is harmless at these doses but a reminder that this is a metal complex being injected on the basis of a skin cream.

05UK status

Cosmetic GHK-Cu: legal, regulated as a cosmetic. Injectable: legal to buy and possess as a research chemical, unlicensed, sold "not for human use". See the legal guide.

COGENT makes two peptide nasal sprays, Semax (FOCUS-01) and Selank (CALM-02), and nothing else. We do not sell the compounds discussed below and this article does not recommend buying them. It exists because people search for these things and deserve an honest answer.