Melanotan II
What is Melanotan II?
Melanotan II (MT-II) is a synthetic analog of the naturally occurring alpha-melanocyte-stimulating hormone (α-MSH). It was originally developed to stimulate melanin production (pigment in the skin), but has also demonstrated effects on sexual function, appetite regulation, and energy balance. It binds to multiple melanocortin receptors (MC1R–MC5R), particularly MC1R (for tanning) and MC4R (linked to sexual arousal).
Potential Benefits Shown in Studies
- Stimulating natural skin tanning by increasing melanin
- Enhancing libido and improving erectile function
- Reducing appetite and supporting fat loss
- Providing potential UV protection by darkening skin
- Supporting mood and energy levels through CNS effects
- Helping regulate body weight and metabolism
Mechanisms of Action
Melanotan II works by:
- Activating melanocortin receptors in the skin and brain
- Stimulating melanin production in melanocytes (skin cells)
- Enhancing sexual desire and erectile function via MC3R and MC4R activity
- Reducing appetite and affecting metabolic regulation through CNS pathways
Its broad receptor activity explains its diverse physiological effects beyond tanning.
Research Highlights
Potent Tanning Agent via α‑MSH Analog Action
Melanotan II is a synthetic analog of alpha‑melanocyte-stimulating hormone (α‑MSH), effectively inducing melanin production through activation of melanocortin receptors, especially MC1R for pigmentation.
Sexual Arousal Through Melanocortin Receptor Activation
MT‑II has shown aphrodisiac-like effects and can induce erections by stimulating MC4R receptors in humans.
Molecular Structure

Ac-Nle-c[Asp-His-D-Phe-Arg-Trp-Lys]-NH₂
C₅₀H₆₉N₁₅O₉
1024.18 g/mol
Note: "c" denotes a cyclic structure; Nle = norleucine
