I accidentally undid years of skin work and didnt realize it until it was too late., At the beginning of November, I started taking melanotan 2 and honestly?, I loved it., My tan deepened Melanotan II A Sun Kissed Look, and a Confident You. Melanotan What It Is and Its Relation to Skin Cancer How Long Does It Take For Melanotan To Work? 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 Peptides for tanning do exist. Melanotan 1 and Melanotan 2 both work at increasing melanin in the skin. Melanotan 1 takes longer to activate. Melnotan 1 is FDA approved. Melanotan 2 does libido,