Your body already makes a hormone that tells your skin to tan. Melanotan 2 is a synthetic peptide engineered to mimic that hormone but in a version that's more potent and Melanotan II for Erectile Dysfunction: What the Evidence Shows and Practical Considerations Melanotan II: Tanning injections, nasal sprays harmful to health Don't risk using tanning products containing melanotan Therapeutic Goods Administration (TGA)