Copper Tripeptide-1: The Copper Form of the GHK Peptide

Copper Tripeptide-1 is GHK-Cu under its cosmetic-label name

Copper Tripeptide-1 is the INCI (International Nomenclature of Cosmetic Ingredients) name for GHK-Cu — the same glycyl-L-histidyl-L-lysine copper(II) complex, labeled for skincare. Its identifiers pin it precisely: CAS 89030-95-5, PubChem CID 71587328, FDA UNII 6BJQ43T1I9, DrugBank DB14683, molecular weight 402.92 Da ^[2]. When a product lists Copper Tripeptide-1, it is declaring copper-peptide content under the name a regulator recognizes. GHK-Cu and Copper Tripeptide-1 are not two ingredients; they are one molecule with a lab name and a label name.

The name matters because it carries the copper. The free tripeptide has its own identity — CAS 49557-75-7, PubChem CID 73587, molecular weight 340.38 Da ^[2] — and a cosmetic label that reads simply 'tripeptide-1' or 'GHK' without the copper designation is, mechanistically, a different proposition. The INCI convention exists in part to make that distinction visible at the point of sale.

What is the difference between GHK and GHK-Cu?

GHK is the free tripeptide (MW 340.38, CAS 49557-75-7); GHK-Cu is the copper(II) chelate (MW 402.92, CAS 89030-95-5). Copper coordination is required for most documented tissue-repair activities: the copper-bound form stimulated MMP-2 expression in fibroblast cultures while the free GHK tripeptide did not reproduce the effect ^[7], establishing that copper chelation is mechanistically essential.

This is the single most important sentence on the site, so it earns repeating in detail. In the fibroblast MMP-2 study, GHK-Cu drove both MMP-2 protein and mRNA upward, with concurrent TIMP-1 and TIMP-2 upregulation — a balanced remodeling signal, not runaway matrix destruction — and the bare GHK peptide, applied identically, did not reproduce it ^[7]. The copper is not decorative. It is the part of the molecule that the fibroblast responds to in that assay.

The corollary is a reading rule. Many studies report systemic, behavioral, or gene-level effects using the free GHK peptide, and those results are real on their own terms — but they cannot be quietly assumed for GHK-Cu, nor can GHK-Cu's copper-dependent matrix results be assumed for free GHK. The literature conflates the two constantly. Tracking which form a paper actually used is the difference between reading this field carefully and reading it badly.

Why copper coordination changes the molecule

The copper(II) ion sits in a square-planar coordination, bound through the histidine imidazole nitrogen, the glycine alpha-amino nitrogen, and a deprotonated glycine-histidine amide nitrogen, with the lysine side chain left free ^[2]. That arrangement does two things at once: it holds copper tightly enough to suppress pro-oxidant free-copper chemistry — the complex's stability constant is roughly log K 16.4 ^[6] — and it positions copper to be delivered to the cuproenzymes of repair, lysyl oxidase chief among them, which cross-links nascent collagen and elastin.

The geometry also explains a practical fact. The blue-violet color of a correctly reconstituted GHK-Cu solution is the expected copper(II) d-orbital absorption and indicates an intact complex; a shift toward brown or green signals oxidation or precipitation ^[6]. The color is a coordination chemistry readout, visible to the eye.

Endogenously, the sequence is released from larger proteins. Proteolysis of SPARC (osteonectin) liberates copper-binding peptides including GHK and KGHK that stimulate angiogenesis, with KGHK the most potent and the activity sequence-specific ^[8]. The body, in effect, keeps the copper-tripeptide motif folded inside its matrix proteins and lets injury cut it loose.

Copper Tripeptide-1 in the regulatory record

Topical Copper Tripeptide-1 is a legal cosmetic ingredient in the US, EU, and UK, with a long marketed use record ^[6]. That legality is specific and narrow: it covers topical cosmetic use. There is no FDA- or EMA-approved drug product containing GHK-Cu for any indication, and injectable, oral, or other systemic formulations are unapproved research chemicals with no established regulatory pathway. The cosmetic name and the cosmetic clearance do not extend to systemic use, and this site does not treat them as if they do.

Copper Tripeptide-1 for Hair: The Controlled-Trial Evidence

The strongest controlled human signal for a Copper Tripeptide-1-related molecule comes from hair research, and it tested a combination, not pure GHK-Cu. In a 6-month trial of 45 men with androgenetic alopecia, a complex of 5-aminolevulinic acid and glycyl-histidyl-lysine peptide (ALAVAX) increased hair count by 52.6 (at 100 mg/mL) and 71.5 (at 50 mg/mL) versus 9.6 for placebo, with no adverse events in any group ^[9]. The mechanism described is non-androgenic — proliferative and angiogenic at the follicle rather than hormonal — which is why copper peptides are studied as a route distinct from 5-alpha-reductase inhibition. Because the human data used a combination formulation, it should be read as supportive of the GHK component, not as proof of GHK-Cu alone.