Viral 'Barbie drug' for tanning can cause brain swelling and even cancer, experts warn Health expert says Melanotan II darkens skin moles and can make melanoma hard to detect Herald Sun To tan or not to tan Atlantic Dermatology & Laser 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.