Hexapeptide-9 vs Copper tripeptide-1
It is put in anti-ageing creams to smooth wrinkles. The one controlled trial, of 96 adults, tested a changed version and was run by a cosmetics company. A skin-care ingredient sold to firm skin, soften wrinkles and regrow hair. The one controlled human trial, of 13 patients, found no skin benefit.
Both sit at grade C: animal and cell studies. Neither is FDA approved.
Evidence
CAnimal and cell studies
CAnimal and cell studies
Human studies cited
Animal or cell studies cited
Why the grade
For wrinkle reduction, the evidence for standard hexapeptide-9 is unpublished supplier data, lab and mouse work, and a small split-face volunteer test of a delivery carrier. The one randomised double-blind trial, published in 2025 by employees of a cosmetics company, enrolled 96 adults but tested a chemically modified cyclised version against a low-concentration retinol and vehicle over 56 days, so the standard ingredient stays at C.
For the skin anti-ageing use, the controlled human evidence is a single randomized trial of 13 patients after CO2 laser resurfacing, which found no objective difference in redness or wrinkles. The rest is gene-expression work in cultured cells, animal wound and lung-injury models, and cosmetic-company studies summarized in reviews written by the peptide's discoverer.
FDA
Cosmetic ingredient
Hexapeptide-9 is a cosmetic ingredient. Cosmetics do not go through FDA drug approval, so it has no approved indication and makes no drug claims; it is listed under its INCI name in skincare formulations.
Cosmetic ingredient
Copper tripeptide-1 is a cosmetic ingredient and sits outside FDA drug approval; no copper tripeptide-1 or GHK-Cu product is approved by the FDA as a drug for any use. Injectable GHK-Cu sold online is not approved and is sold as a research chemical.
Sold for
Hexapeptide-9 is marketed in anti-aging serums as a collagen fragment that signals skin cells to rebuild the dermis and smooth wrinkles.
Copper tripeptide-1 is marketed in serums as a collagen-building, wound-healing peptide that firms skin, softens wrinkles and regrows hair.
Studies say
The only controlled human trial tested a modified molecule and was run by the manufacturer, and the data for standard hexapeptide-9 are laboratory assays, so the grade is C.
Cell and animal studies show it switches on repair genes and speeds wound closure, but the one blinded human trial found no measurable skin benefit over the control regimen, so the evidence is C.
Class
Signal peptide
Carrier/copper peptide
Route
Topical
Topical