https://en.wikipedia.org/wiki/Melanotan_II says it is banned in the United States, and anything you get on the black market isn't guaranteed to be pure.

Where does it say it's banned?

Second paragraph mentions "regulatory restrictions".

Clinuvel Pharmaceuticals intended to offer it as a cosmetic, but abandoned this pursuit in the 2000s due to regulatory restrictions and concerns about the promotion of suntanning. Unlicensed Melanotan II is found on the internet, although health agencies advise against its use due to lack of testing and regulatory approval.

It’s banned for cosmetic use. You can still buy it as a “research chemical”.

Do not buy it.

https://news.ycombinator.com/item?id=46345971

I’m pretty sure Melanotan carries the risk of retinal pigmentation, or at least that was the case with the original. Not sure if II is different.

BEWARE.

Melanotan is dangerous, sadly.

Tanning causes melanocyte production in your epidermis. Melanotan causes it throughout your body in an uncontrolled manner. In a wide variety of unrelated tissues.

It can lead to uncontrolled melanocyte production that doesn't shut off - cancer. Aggressive melanomas.

It disrupts normal hormone signalling which may downstream cause a variety of deleterious health effects and disease states.

There are also crazy reports of kidney failure, which may or may not be caused by the drug.

https://pmc.ncbi.nlm.nih.gov/articles/PMC7148395/

https://pubmed.ncbi.nlm.nih.gov/23121206/

https://www.actasdermo.org/en-eruptive-dysplastic-nevi-follo...