Melanotan II vs PT 141: Key Differences in Research Nasal tanners claim to work by using Melanotan II, a chemical that darkens skin pigmentation. It is illegal to sell medicinal products containing Melanotan II in the UK but since the tanners are sold Nasal tanning sprays: unsafe and potentially harmful. Chartered Trading Standards Institute posted on the topic LinkedIn You Should Avoid Using Nasal Tanning Sprays Viral 'Barbie drug' for tanning can cause brain swelling and even cancer, experts warn