GHK vs GHK-Cu: What Is the Difference Between the Peptide and the Copper Complex?

Searching for copper peptides, you will see both “GHK” and “GHK-Cu.” They are related but not identical. Here is what separates them.

GHK: the bare tripeptide

GHK is the sequence glycyl-L-histidyl-L-lysine: three amino acids. On its own it has a strong attraction to copper ions, which is why it is classed as a carrier peptide.

GHK-Cu: the copper complex

When GHK binds copper(II), it forms GHK-Cu. The histidine side chain and nitrogen atoms in the peptide backbone hold the copper in place. The complex is blue in solution, because copper absorbs orange-red light.

Why copper matters

• Copper is a cofactor for lysyl oxidase, which cross-links collagen and elastin
• Copper helps antioxidant enzymes such as superoxide dismutase work
• The complex can deliver copper to cells that need it

Does GHK alone do anything?

In the body, free GHK picks up copper readily, so the distinction is partly academic in living systems. In research, though, whether a study used GHK or GHK-Cu, and at what ratio of copper to peptide, can change results. That is why published methods matter.

What researchers check

• Is the product the copper complex or the free peptide?
• What is the peptide-to-copper ratio?
• What are the pH and storage conditions? Copper peptides are sensitive to both

The research listings on this site are for the copper form: see GHK-Cu and Topical GHK-Cu.

Browse the research compounds

Explore GHK-Cu and Topical GHK-Cu. Every compound is sold for laboratory research use only, and batch-specific lab reports are on the COA page. You can also browse the full shop.

Related reading: GHK-Cu complete guide, KPV complete guide and the research library.

This article is educational and summarizes published laboratory research. It is not medical advice. Compounds mentioned are sold for research use only, not for human or veterinary use.

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For laboratory research use only. Not for human or veterinary use, and not intended to diagnose, treat, cure or prevent any condition. This article is educational and is not medical advice.