“It’s February 15, and I’m going to do my first injection of Melanotan II,” says YouTuber Kimberly Pratt in a video documenting her experience with the controversial tanning peptide. She describes how the injectable, dubbed the “Barbie drug,” gave her a beautiful golden tan and appeared to help with a sun-triggered skin condition, while acknowledging side effects like nausea, libido changes and darkening of existing pigmentation. “Check out how pale I am right now. But give me two weeks,” she went on. “We’re about to glow up for summer.” Related Articles The peptide has gained traction on TikTok, where users document their results, and has made its way into dinner table conversations in Los Angeles . Melanotan II, known as MT-2, sits at the intersection of beauty culture, biohacking and a rapidly expanding peptide market. Chemically, it’s an unlicensed synthetic analogue of alpha-melanocyte-stimulating hormone, designed to stimulate melanin production in the skin.…