Start with the kind of evidence
A review gathers earlier work; a trial tests a question in a particular group. A case report describes an individual experience. They can all be useful, but they can't answer the same questions.
These links support the claims beside them. Listing a paper here doesn't mean it establishes a benefit for every product or route.
Copper peptides and skin
The topical review
Mortazavi and colleagues, 2025. Topically applied GHK as an anti-wrinkle peptide reviews delivery and the limited human research. It isn't a new cream trial.
Older appearance findings
Pickart and colleagues, 2015. GHK and skin regeneration reviews lab and topical findings. Some cosmetic reports it cites weren't full medical-journal papers.
Collagen in cells
Maquart and colleagues, 1988. Collagen production in fibroblast cultures increased with GHK-Cu. These were human cells in a lab, not treated skin in people.
After laser treatment
Miller and colleagues, 2006. The small post-laser copper-peptide study found higher satisfaction without significant measured improvements in redness or wrinkles. The treatment setting matters.
A different pigment mixture
Hong and colleagues, 2025. Palmitoyl copper peptide with acetyl tyrosine increased pigment in human and mouse melanoma cell lines. It didn't test ordinary GHK-Cu alone or people's skin.
Melanotan II
The wider research story
Hadley and Dorr, 2006. Melanocortin research milestones connects pigmentation and sexual-function research. It explains why a tanning description is incomplete.
The selected human trial
Wessells and colleagues, 1998. The erectile-function study tested men with psychogenic erectile dysfunction. It didn't establish long-term tanning safety.
Mouth pigment changes
Bonchev, 2026. Pigment changes after Melanotan II injections followed one man's cheek and gum changes. Their course after stopping differed.
The kidney report
Peters and colleagues, 2020. Renal infarction and Melanotan II discusses a possible association with kidney injury. It doesn't establish how often this happens.
Approval and access
The FDA's compounding safety-risk page, current as of April 22, 2026, lists injectable GHK-Cu and Melanotan II as nominated but withdrawn. Their safety concerns remain listed.
The FDA's explanation of compounded-drug risks distinguishes compounding from product approval. Compounded medicines aren't FDA-approved.
The FDA's cosmetic-or-drug guide explains how intended use affects a product's category. Appearance claims and medical claims need that distinction.
HHS's cross-state licensing guide explains how location affects remote care. An online visit doesn't bypass state licensing rules.