Can You Use Melanotan Long Term? Been testing out MT 1 peptide (Melanotan I) lately and honestly this stuff works. Originally developed for skin protection and UV resistance, but most people know it now for boosting melanin and giving 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, Insights into Tanning Biology and Tanning Products JCAD The Journal of Clinical and Aesthetic Dermatology