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 Tanning, fake tan and Melanotan Cancer Research UK Protein tyrosine phosphatase 1B in metabolic diseases and drug development Nature Reviews Endocrinology You Should Avoid Using Nasal Tanning Sprays The Peptide Craze Ground Truths Unlicensed weight loss drugs marketed on social media as 'prizes' Weight loss drugs The Guardian