Viral 'Barbie drug' for tanning can cause brain swelling and even cancer, experts warn The weight loss drug Melanotan 2, also known as the Barbie drug, has taken social media by storm. Melanotan 2 is widely promoted online, despite it being illegal and dangerous in the UK. Amber Haque Melanotan II is the product that's been dubbed the "Barbie drug" on social media, and promises to give users a tan without the sun but it can have serious side effects including, in rare cases, Brits buy 17 illegal 'Barbie' tanning injections that 'lead to kidney failure, brain swelling and hallucinations'