Melanotan 2 is known as the 'tanning peptide' because it helps stimulate melanin production in the skin, leading to a deeper and longer-lasting tan. It's popular with people who want to tan with less sun exposure or maintain a bronzed look year-round. One added bonus is its potential libido-enhancing effects. Melanotan 2 is also known to increase sexual desire in both men and women. While not originally intended for this purpose, it's become an unexpected benefit that some users enjoy alongside their improved complexion.