What is GHK-Cu? The copper peptide explained

GHK-Cu is one of the most researched copper peptides, and one of the few you can identify at a glance: it's bright blue. This guide explains what it is, why it's blue, and what laboratory research has looked at.

What is GHK-Cu?

GHK-Cu (also written GHK Cu or copper tripeptide-1) is a complex of copper with a tiny peptide of three amino acids: glycine, histidine and lysine (Gly-His-Lys). GHK was first isolated from human plasma in the 1970s, and it binds copper very strongly, forming the GHK-Cu complex.

• Sequence: Gly-His-Lys, complexed with copper(II)
• Molecular weight: about 401.9 g/mol
• CAS number: 89030-95-5
• Appearance: blue powder

Why is GHK-Cu blue?

The colour comes from the copper(II) ion. Copper complexes like this absorb red and orange light, so they look blue. A blue powder is exactly what you should expect. Our certificate shows a copper content of 15.2%, which is in the expected range for the complex. If GHK-Cu arrives white, that's a sign something is wrong.

What has research looked at?

GHK-Cu has been studied for decades, mostly in cell and tissue models. Main themes include:

• Extracellular matrix: collagen, elastin and related proteins in skin-cell models.
• Wound-healing models: tissue remodelling studies.
• Copper transport: how copper is carried and delivered to cells.
• Gene expression: studies of how GHK affects activity of large sets of genes in cell models.
• Formulation research: it is widely studied as an ingredient in cosmetic formulation research.

GHK vs GHK-Cu

GHK is the peptide on its own; GHK-Cu is the peptide bound to copper. Most research focuses on the copper complex, because copper binding is central to how it behaves in the lab.

Handling and storage

Like our other lyophilised peptides, keep the sealed vial at 2–8°C for short-term storage or at −20°C for long-term storage, away from light and moisture. See our full guide on how to store research peptides.

What to look for on the certificate

Check HPLC purity, identity by mass spectrometry, and copper content. Our current batch tested at 99.2% purity by HPLC, with identity confirmed by ESI mass spectrometry. The full certificate is on the GHK-Cu product page.

A note on the evidence

Much of the research is laboratory-based, and results in cells or animals don't necessarily apply to people. GHK-Cu sold as a research peptide is for laboratory use only.

Buy GHK-Cu in the UK

We supply GHK-Cu 50mg with its certificate of analysis on the product page, tracked UK delivery, and free collection near Cambridge and Essex. Browse our melanocortin and copper peptides.

All products sold by Absolute Peptides are for laboratory research use only. Not for human or veterinary use. This guide summarises published research and is not medical advice.