Melanotan II is an analogs of the peptide hormone alpha-melanocyte-stimulating hormone (α-MSH) that induces skin tanning. MT 2 plays a role in stimulating melanogenesis and thus provides a protective mechanism against U V rays since under its actions melanocytes are able to increase production and secretion of the hormone melanin. Research has also found that MT 2 has a positive effect on libido due to its aphrodisiac properties. Additionally, MT 2 exhibits a mild positive fat-mobilizing effect.