Test Subjects have found in some case studies that Melanotan II (MT2) is a synthetic peptide, which is a lab-made analogue of the naturally occurring melanocortin peptide hormone alpha-melanocyte-stimulating hormone (α-MSH). This hormone is involved in skin color regulation.

The primary purpose of α-MSH and, by extension, Melanotan II, is to stimulate melanogenesis, the process by which the skin’s pigment cells (melanocytes) produce melanin, the pigment responsible for skin color. When MT2 binds to melanocortin receptors in skin cells, it leads to an increase in the production of melanin, which can result in a darker pigmentation of the skin. MT2 has been observed to have other potential effects. It can influence sexual arousal, appetite suppression, and even lipolysis (the breakdown of fat cells).

Melanotan II has been associated with certain risks and side effects. These include but are not limited to nausea, flushing, decreased appetite, spontaneous erections in males, and darkening of moles or new mole formation.