Melanotan II

Melanotan II is a synthetic cyclic heptapeptide analog of alpha-melanocyte-stimulating hormone (alpha-MSH) developed at the University of Arizona. It was originally designed as a sunless tanning agent to reduce the risk of skin cancer by stimulating melanin production without UV exposure. The peptide acts as a non-selective agonist of melanocortin receptors MC1R through MC5R.

The primary mechanism involves activation of the MC1R receptor on melanocytes, stimulating the production and distribution of melanin pigment in the skin. This results in progressive skin darkening (tanning) independent of UV radiation exposure. Due to its non-selective melanocortin receptor activation, Melanotan II also affects MC4R (influencing sexual arousal and appetite) and MC3R (involved in energy homeostasis), producing multiple systemic effects beyond pigmentation.

Research has demonstrated Melanotan II's efficacy in increasing skin pigmentation, with studies showing measurable increases in melanin density after treatment. Its effects on sexual function led to the development of the related drug PT-141 (Bremelanotide), which selectively targets the MC4R receptor. Studies have also shown appetite-suppressive effects and potential photoprotective benefits. However, research has noted side effects including nausea, facial flushing, and the potential to darken existing moles, requiring careful monitoring.