GHK-Cu: The copper peptide with decades of research behind it

GHK (glycyl-L-histidyl-L-lysine) was isolated from human plasma by Loren Pickart in the 1970s as a factor that appeared to reverse age-related suppression of protein synthesis in liver tissue. The copper(II) complex, GHK-Cu, is the form that dominates cosmetic and research conversations today. That origin story is a published isolation — a genuine starting point — and everything after it rewards the same careful reading.

What the 2018 review actually covers

Pickart and Margolina’s 2018 International Journal of Molecular Sciences review (PMC6073405) is the paper often compressed into “GHK-Cu turns on 4,000 genes.” The paper does report Broad Institute Connectivity Map gene-expression work, and it summarizes topical human studies: a 12-week facial cream on 71 women; an eye cream on 41 women; a thigh-collagen comparison against vitamin C and retinoic acid; a nano-lipid GHK-Cu serum versus Matrixyl 3000 on wrinkle volume. Those are cosmetic, topical, and in several cases open-label or industry-adjacent. They are real data points. They are also a different experimental setting from a lyophilized research lot reconstituted for bench work.

A topical cream study and a research powder can share a sequence while answering different questions.

In fibroblast culture, GHK-Cu has been reported to alter collagen, elastin, MMP-1, MMP-2, and TIMP-1 at nanomolar concentrations. That is a bench finding with a dose unit of nM — useful for thinking about mechanism, and a reminder that culture concentrations and catalog milligrams live in different measurement worlds.

If you work with GHK-Cu in a laboratory, the interesting questions are still close to Pickart’s originals: copper handling, extracellular-matrix transcription, and whether a tripeptide-copper complex acts more like a signal or a nutrient. Those questions fit an experiment design. They are also why this compound keeps showing up in serious dermal research decades later.