What Is GHK-Cu? The Copper Peptide Behind Copper Theory

Meet GHK-Cu

GHK-Cu — copper tripeptide-1 — is a tiny chain of three amino acids bound to a copper ion. It occurs naturally in human plasma, but its levels fall as we age. Over decades of research it has become one of the most-studied peptides in cosmetic skin science, prized for its role in supporting the look of healthy, resilient skin.

Why copper?

Copper is an essential trace mineral involved in many of the skin’s natural processes. Delivered as part of the GHK tripeptide, it’s carried in a form the skin recognises. In cosmetic studies, GHK-Cu has been explored for its association with the appearance of firmness, smoother texture, and a more even, refreshed complexion.

Why 2%?

Concentration matters. Many products list copper peptides far down the ingredient deck, at levels too low to do much. Copper Theory uses a meaningful 2% dose of GHK-Cu — high enough to be the star of the formula, not a marketing footnote.

The blue tint is the point

Copper peptides carry a natural blue colour. If a “copper peptide” serum is perfectly clear, it’s worth asking how much is really inside. Copper Theory’s subtle blue is the active itself — no dyes required.

How to use it

Apply 3–5 drops to clean skin morning and evening, let it absorb, then follow with moisturiser. Pair it with gentle cleansers and daily SPF. Like most peptides, GHK-Cu rewards consistency — give it a few weeks of daily use.

The bottom line

GHK-Cu is a rare thing in skincare: a genuinely well-researched active with a clear story. We built Copper Theory around it, paired with Tremella mushroom for hydration, and left out the filler. Read more about the science →

This article is general education about cosmetic ingredients. Mycena Skin products are cosmetics, not drugs, and aren’t intended to diagnose, treat, cure, or prevent any condition.