Melanotan II (Tan Jabs): Why They're Not Worth The Risk 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 Melanotan II Nasal Spray Achieve Tanned Skin & Wellness Benefits Viral 'Barbie drug' for tanning can cause brain swelling and even cancer, experts warn Avoid nasal tanning sprays or nasal tanners entirely. These products promise an all over tan without sun exposure but they are unregulated, can be unsafe, and contain potentially risky substances like Melanotan 2.