Researchers are starting to get a closer view of the various gray-market peptides making the rounds on the back of the “looksmaxxing” trend, and it isn’t looking good.

In a new interview with Axios, Anthony Rossi, a dermatological surgeon at Memorial Sloan Kettering Cancer Center, warned that the substance “Melanotan II” isn’t exactly the best thing you can put in your body.

Also known as the “Barbie drug,” melanotan II is an unregulated, synthetic hormone believed to stimulate pigment cells and encourage melanin production. It’s a popular product for folks looking for a shortcut to a golden glow, but as Rossi explains, it’s much more trouble than it’s worth.

Not only does it require constant injections to work, but according to Rossi it can be outright harmful, even leading to skin cancer in some cases.

“People who inject melanotan, their moles start to change,” the surgeon told Axios, adding that he’s had to remove cancerous moles from at least one melanotan II user. “I don’t really see a medical benefit of it at all.”

While studies are still way behind the market as far injectable peptides are concerned, evidence is growing that melanotan II probably isn’t the best thing to inject into your bloodstream.

For example, a 2012 case study tells the story of a 16-year old girl who used melanotan II in conjunction with a UV tanning bed, resulting in the intensification of over 50 moles on her skin. At least one of them had to be surgically removed, the case study explains, as it was slowly enlarging, likely as a result of the injectible tanning treatment.

A 2014 clinical study on the use of melanotan II found a similar correlation, after a 20-year old user was diagnosed with melanoma following a four-week injection regiment.

At the end of the day, if you’re looking for that sun-kissed bronze hue, gray-market peptides might be one of the worst ways to achieve it.

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