Dermatologists in Illinois and Michigan just published a case report in JAAD Case Reports. A 46-year-old man started daily Melanotan II injections with a supply he got from his gym. About five weeks in he noticed his moles changing and stopped. A month after that, a lesion on his back came back as early-stage melanoma.
The authors are careful, and you should be too. He'd had melanoma before, he has a family history of it, and he'd been in tanning beds two or three times a week for over a year before any of this started. The authors say outright they can't rule those out. One case can't establish cause, and anyone telling you it does is selling something.
So why am I sending it?
Because the mechanism is no mystery, and that's what makes this one worth your time.
Melanotan II is a melanocortin agonist, which means it switches on a family of receptors called melanocortin receptors. The one that matters here is MC1R, which sits on melanocytes, the cells that make pigment. Switch MC1R on and the cell makes more eumelanin, the dark pigment. That's the whole reason the compound tans you. The tan is the receptor doing exactly its job.
Melanocytes are also the cells melanoma starts in.
So here's the honest version. A compound that tells pigment cells to turn up their activity is being injected by people, some of whom already have sun-damaged skin and a history, and nobody has run the study that would tell us whether that matters. I don't mean a study showing it's dangerous. I mean no study at all. Case reports are what the literature produces when nobody has run the big one.
What would actually settle it.
You'd want a few thousand users followed for years against matched non-users, with dose and duration recorded, looking at whether risk climbs with exposure. Nobody's funding that. There's no patent at the end of it, and a study like that costs tens of millions. That's the real reason this question stays open, and it's the same reason half the compounds in your rotation have no long-term data either. The missing evidence is a budget problem, and it tells you nothing in either direction.
If you use it.
The useful lesson here is a skin check, and knowing what you're looking at between checks. The man in the report noticed the change himself and went in, and his came back early-stage.
And then there's the timing.
Melanotan II is on the docket for FDA's next compounding advisory committee, expected before the end of February, alongside GHK-Cu, LL-37, Dihexa and PEG-MGF. Five peptides, one meeting, no date announced yet.
A committee taking up Melanotan II a few months after a melanoma case report lands in the literature isn't a coincidence I'd bet against.
All five are on the tracker with what still has to happen to each one, and the rows change the day the panel date is set.