GHK-Cu vs Acetyl hexapeptide-8
A copper-based ingredient sold in skin creams and injections for wrinkles, hair loss and healing. It speeds wound healing in rats, but no proper human trial exists. It is a cream ingredient sold as a needle-free way to smooth expression lines. Two small trials disagreed: one showed less wrinkling, one showed none.
Acetyl hexapeptide-8 has the stronger evidence, grade B (some human evidence) against grade C for GHK-Cu. GHK-Cu: Not approved. Acetyl hexapeptide-8: Cosmetic ingredient.
Evidence
CAnimal and cell studies
BSome human evidence
Human studies cited
Animal or cell studies cited
Why the grade
For skin repair and wound healing, the use GHK-Cu is best known for, the primary studies in hand are cell cultures, rat and mouse experiments and one macaque hair model. The human cosmetic results that reviews describe come from manufacturer-run tests that are summarised and not published in full, so no controlled human trial with a known sample size can be named.
For wrinkle reduction there is one randomized placebo-controlled trial in 60 Chinese adults showing a benefit, a 19-person split-face double-blind study showing none, a 26-patient uncontrolled series and the manufacturer's original volunteer study. Skin penetration work in human and animal skin finds very little of the peptide reaches the dermis, which leaves the mechanism in doubt. Small samples and conflicting results keep this at B.
FDA
Not approved
GHK-Cu is not approved by the FDA for any use. As copper tripeptide-1 it is sold in cosmetics, which sit outside FDA drug approval. The FDA placed the injectable form in Category 2 of its compounding list in 2023 over safety risks, and the agency now lists that nomination as withdrawn; it plans to bring GHK-Cu before its Pharmacy Compounding Advisory Committee by the end of February 2027.
Cosmetic ingredient
Acetyl hexapeptide-8 (Argireline) is a cosmetic ingredient, and the FDA does not approve cosmetic ingredients before sale; products containing it are regulated as cosmetics so long as they claim only to improve appearance. It is not an approved drug for any use.
Sold for
GHK-Cu is sold as an anti-aging and wound-healing peptide, in serums for wrinkles and hair thinning and as an injectable for recovery.
Argireline is marketed as a needle-free alternative to Botox that relaxes expression lines when applied as a cream or serum.
Studies say
Cell and animal work shows that GHK-Cu raises collagen production and speeds wound closure in rats, but the human evidence is limited to cosmetic tests reported inside reviews, which is why the grade is C.
One small randomized trial found a measurable reduction in eye-area wrinkles and another found none, while penetration studies show almost none of the peptide reaches the muscle layer, so the evidence supports a modest surface effect at best (grade B).
Class
Copper-binding tripeptide
Neurotransmitter-inhibiting peptide
Route
Several routes
Topical