Pentapeptide-18 vs Copper tripeptide-1
It is a cream ingredient sold as a Botox alternative for expression lines. Two small studies of 20 people each had no comparison group, so the proof is weak. 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
The human evidence is two small uncontrolled studies: a 20-volunteer, two-month test of pentapeptide-18 creams at three strengths, in which only the strongest reduced measured wrinkle length, and an eight-week test in 20 women of a cream that also contained retinol. Neither had a vehicle or placebo control, and the manufacturer has not published its own trial data. Uncontrolled series put it at C for expression lines.
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
Pentapeptide-18 is a cosmetic ingredient, sold under the trade name Leuphasyl. Cosmetic ingredients in the United States are not reviewed or approved by the FDA before sale, so there is no FDA approval to cite for or against it.
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
Pentapeptide-18 is sold as a topical alternative to botulinum toxin that softens expression lines, usually paired with acetyl hexapeptide-8 (Argireline).
Copper tripeptide-1 is marketed in serums as a collagen-building, wound-healing peptide that firms skin, softens wrinkles and regrows hair.
Studies say
Two small uncontrolled studies in 20 volunteers each report shorter or fewer wrinkles after weeks of use, one of them with retinol in the same cream, which is grade C support at best.
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
Neurotransmitter-inhibiting peptide
Carrier/copper peptide
Route
Topical
Topical