Sitting in the passenger seat of a car, a high school teen clutches an insulin needle beneath her pursed lips. She overlays the social media video with a sexually charged caption: “when he says he wants to pin me so i lowkey grab the r3ta and he looks at me weird.” No, this isn’t a new sexual fetish that today’s young people are into. What the 17-year-old is referring to is retatrutide — a next-generation, triple-agonist weight-loss drug that the teen has managed to get her hands on for cheap as a quick fix to look more toned. The peptide supposedly suppresses appetite, controls blood sugar, and increases energy. She’s been injecting 0.5mg every week for a month and has already lost 10 pounds. The high schooler also injects melanotan I, a tanning peptide that increases melanin production even with minimal sun exposure. Sydney Haddon seen showing her “stack” of peptides. Lone Pine Press for NY Post The teen sources her products through her boyfriend’s “connection” on Telegram, an encrypted messaging app.…