Short answer: The only FDA-approved peptide in this space is Scenesse (afamelanotide), and only to increase pain-free light exposure in adults with a rare disease called EPP. GHK-Cu has small trials of face creams, but injected GHK-Cu has no human trials. Melanotan II darkens skin but has case reports of melanoma, kidney damage and priapism, and no approval anywhere we found.
| Compound | Best evidence | What it shows |
|---|---|---|
| GHK-Cu, on the skin | Small or early human studies | Used in cosmetic creams. A 2026 systematic review says most human trials are small studies of face creams by a few authors. |
| GHK-Cu, injected | No published studies found | We found no published human trial of injected GHK-Cu. FDA flags injectable GHK-Cu for possible immune reactions and limited human data. |
| Melanotan II | Small or early human studies | A 1996 pilot in 3 men showed tanning in 2, with nausea, sleepiness and spontaneous erections. Later case reports describe serious harms. |
| Afamelanotide (Scenesse) | Approved for a different use | A 16 mg implant approved for erythropoietic protoporphyria (EPP), a rare light-sensitivity disease. It is not approved for cosmetic tanning. |
"Animal or lab studies only" means no published human trial for this goal that we could find. Results in rats or cells often do not carry over to people. Compounds that are not FDA-approved have no tested label for dose, purity or safety.
GHK-Cu is a copper-bound three-amino-acid peptide (glycine, histidine, lysine) found naturally in blood, saliva and urine. Levels fall with age. Lab and animal work shows it affects collagen and wound repair, and reviews by its original researcher report that cosmetic creams tightened skin and reduced fine lines.
An independent 2026 systematic review screened 1,247 records and kept 64. Its summary: decades of lab and animal evidence, but the human literature "remains thin and fragmented." Most randomized trials are small and test face creams. It also noted that about 35% of the GHK-Cu research includes authors from one company. Hair growth is listed as an area that still needs proper human trials.
Injected GHK-Cu is a separate question. We found no human trial of it, and FDA lists injectable GHK-Cu as a compounding risk because of possible immune reactions and limited human data.
Melanotan II is a synthetic copy of alpha-MSH, the hormone that tells skin cells to make pigment. It also acts on other melanocortin receptors, which is why it causes erections and nausea. The first human pilot (1996) dosed 3 men for two weeks; 2 developed darker skin, and side effects included nausea, sleepiness and erections lasting 1 to 5 hours.
Since then, the reports are about harm, not benefit:
Afamelanotide is a related alpha-MSH analog that went through full trials. The US label approves it to "increase pain free light exposure in adult patients with a history of phototoxic reactions" from EPP, a genetic disease where sunlight causes severe pain.
None of this applies to melanotan II bought online, which is a different molecule with no approval.
Terms on this page: Peptide · Injection site rotation · Research use only (RUO)