The Peptide Atlas
GHK-Cu
A three-amino-acid peptide bound to copper, found naturally in your blood, saliva, and wound fluid.
Class
Copper-binding repair peptide
Evidence
Early research
Status
Studied in research settings; used in cosmetics as a cream ingredient.
Forms
Creams and serums; sold as injection in the gray market, untested
What people use it for
Skin: firmness, fine lines, and healing, mostly in serums and creams. Some use it on hair.
The signal
When tissue gets damaged, the body releases GHK at the injury site, where it helps coordinate the cleanup and rebuilding: collagen production, blood-vessel growth, and the enzymes that remodel skin. Blood levels of it fall substantially between your 20s and your 60s [1].
How it works
It carries copper into cells and switches on genes involved in tissue repair. Gene-expression studies show it resets hundreds of genes toward a repair state, which is a big part of why it became a cosmetics ingredient [2].
What the research shows
The lab and gene-level research is extensive. The human evidence is mostly small cosmetic studies of creams, summarized in the published reviews [1], showing improvements in skin thickness, elasticity, and the look of fine lines. Injections haven't been studied in people.
What people get wrong
That the skincare results say anything about injections. The studies people cite used creams on skin, which is also where the plausible mechanism lives. And that more copper is better generally: the peptide's job is delivering copper in a controlled way, which is different from supplementing copper.
References
- Pickart L, Margolina A. Biomed Res Int (2015). GHK Peptide as a Natural Modulator of Multiple Cellular Pathways in Skin Regeneration. PubMed
- Pickart L, Margolina A. Int J Mol Sci (2018). Regenerative and Protective Actions of the GHK-Cu Peptide in the Light of the New Gene Data. PubMed
Last reviewed 2026-08-24. Every reference is verified against the primary literature at review time. How the Atlas grades evidence