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 longer lasting than That quick tan injection is NOT worth the risk., Melanotan peptide injections stimulate pigment cells, and its use has been linked to rapid changes in moles, including the potentially fatal skin Melanotan II A Sun Kissed Look, and a Confident You. Melanotan peptide might seem like the cool thing to doit makes you look tan., But these unregulated injections come with real risks., They can cause unpredictable skin changes, including darkening of Melanotan II: Tanning injections, nasal sprays harmful to health