pt-141 or bremelanotide is the generic term for a research peptide being studied for its possible use in helping to improve sexual dysfunction in both men (erectile dysfunction or impotence) and women (sexual arousal disorder). pt-141 was developed from the tanning peptide melanotan 2, which is a synthetically produced variant of a peptide hormone naturally produced in the body that stimulates melanogenesis that is known as alpha-melanocyte stimulating hormone. msh, activates certain melanocortin receptors in the process of exerting its effects. indeed, msh also exerts potent influence over lipid metabolism, appetite, and sexual libido. resultantly, pt-141 has been shown in studies to exhibit libido-enhancing effects by activating the melanocortin receptors mc1r and mc4r, but not skin tanning. melanotan 1 and melanotan 2 have been researched for their use in protecting against the harmful effects of ultraviolet radiation from sunlight due to their melanogenesis-stimulating properties.