Peptides for skin and hair: what the evidence says
GHK-Cu, the "copper peptide," is in many anti-aging serums and is also sold as an injectable. Melanotan II is used for tanning. Here is what the research shows.
This page has not yet been reviewed by a credentialed medical professional. It is educational and is not medical advice.
GHK-Cu has encouraging lab and animal results but very few clinical studies in skin, and none for injections. Melanotan II is unapproved and regulators have warned against it.
What people use, ranked by evidence
Strongest evidence first. The numbers come live from PubMed and ClinicalTrials.gov.
-
GHK-Cu
Animal studies onlyWhat people use it for: Anti-aging skincare, wrinkles, hair and wound healing. Common in cosmetic serums.
What the evidence says: Strong lab data and some animal wound-healing work. Reviews note a "surprising absence" of clinical studies of GHK-Cu in wrinkle products, and no human data for injection.
1 randomized trial 3 registered trials Approved for: Cosmetic ingredient (topical); no approved drug use Sport: Check listGHK-Cu profile → -
Melanotan II
Human trialsWhat people use it for: Tanning and libido. Sold online; regulators have warned against it.
What the evidence says: Small human studies exist, but it is unapproved and carries recognized safety concerns.
4 randomized trials 1 registered trial Not approved as a medicine Sport: Check listMelanotan II profile →
Common questions
Does GHK-Cu work for wrinkles?
Cell studies show it can boost collagen production. A 2025 review found a surprising absence of clinical studies in skincare and open questions about how much reaches the skin.
Is injectable GHK-Cu proven?
No. There are no controlled human studies of injected GHK-Cu for skin, hair or healing.
Is melanotan II safe for tanning?
It is not an approved medicine, and regulators have warned against it. Human studies are small, so its safety is not well understood.
Go deeper
Other goals
"What people use it for" describes common claims, not recommendations. Educational only, not medical advice.