Viral 'Barbie drug' for tanning can cause brain swelling and even cancer, experts warn Melanotan II reverses memory impairment induced by a short term HF diet ScienceDirect Lets look at sunless tanning, ., Firstly theres the injections and nasal sprays which typically have an active ingredient called melanotan. This is a synthetic compound that stimulates the Melanotan II (Tan Jabs): Why They're Not Worth The Risk