GHK-Cu (Copper Peptide)
A copper-binding tripeptide used as an ingredient in topical cosmetic products.
What it is
GHK-Cu is a naturally occurring copper-binding tripeptide found in human plasma, whose levels decline with age. In commerce it is a cosmetic ingredient — one of the few peptides in this library with a legitimate over-the-counter home.
Topical GHK-Cu has small human studies on skin appearance — fine lines, elasticity, wound-adjacent endpoints — the kind of evidence cosmetic regulation contemplates, well short of drug-level proof. Injectable GHK-Cu sold online is a different product in a different (unregulated) channel and shouldn't borrow the topical evidence.
What researchers have actually studied it for
Skin appearance and wound-adjacent endpoints in small topical studies; broader regenerative claims rest on lab work.
How it works
The tripeptide glycyl-histidyl-lysine binds copper and ferries it into tissue, where lab studies show it stimulating collagen and glycosaminoglycan synthesis, modulating metalloproteinases (the enzymes that remodel skin), and nudging gene expression toward repair programs. Cosmetic formulations bank on those dermal effects.
Where it came from
Discovered in 1973 by biochemist Loren Pickart, who noticed old liver tissue behaved younger in the presence of a plasma factor — GHK. Five decades of his and others' lab work built the repair narrative; the cosmetics industry adopted it broadly in the 1990s, making the blue copper-peptide serum a category staple.
What the research record actually contains
- Decades of cell and animal studies on collagen synthesis and tissue remodeling.
- Small controlled human studies of topical formulations: modest improvements in fine lines, elasticity and skin density.
- Hair-follicle lab work underpinning haircare use; controlled human regrowth trials absent.
- No human evidence for injectable use — a different route with no oversight.
What's known about risks
Topically: long cosmetic history, low irritation, well tolerated. Injectable gray-market use has no human safety data — and copper delivery by injection is not a casually self-administered idea.
Where it stands legally
Lawful as a cosmetic ingredient in topical products. Injectable versions have no approved or compounded pathway — research-chemical territory.
Worth asking a licensed provider
- 1.For my skin goals, how does copper peptide compare with proven options like retinoids?
- 2.Is there any reason to consider more than topical use? (The honest answer should be no.)
- 3.What realistic timeline and effect size should I expect from cosmetic-tier evidence?