Melanotan II (MT-2)

Melanotan II (MT-2) is a synthetic peptide analogue of the endogenous α-Melanocyte-Stimulating Hormone (α-MSH). Structurally, it is a shorter, cyclic peptide, a modification that distinguishes it from the linear Melanotan I and contributes to its different biological activity profile.

Its mechanism of action involves functioning as a non-selective agonist for the melanocortin receptors. While it potently activates the Melanocortin 1 Receptor (MC1R) to stimulate melanogenesis and cause skin pigmentation, it also strongly binds to other melanocortin receptors, notably the MC3R and MC4R, which are highly expressed in the central nervous system.

This broad receptor engagement results in a wider range of physiological effects than the more selective Melanotan I. In addition to inducing skin tanning, MT-2 is well-documented in research to affect functions regulated by the brain, including increasing libido, suppressing appetite, and influencing metabolism. Its action on these central receptors is also responsible for common side effects such as facial flushing, nausea, and spontaneous erections. MT-2 is an experimental compound that has not been approved for therapeutic use by major regulatory bodies.