Melanotan II
PreclinicalMelanocortin agonist studied for pigmentation
Also known as: MT-II, MT-2, Melanotan 2
Melanotan II is a synthetic cyclic analog of α-MSH that activates melanocortin receptors, studied for skin pigmentation (tanning) and, via MC4R, libido — but it is unapproved and carries notable safety concerns.
Molecular & research data
- Sequence
- Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2
- CAS number
- 121062-08-6
- Molecular formula
- C50H69N15O9
- Molecular weight
- 1024.2 g/mol
- Half-life
- ≈1 hour (variable)
- Primary targets
- Melanocortin receptors (MC1R, MC4R)
- Routes (research)
- Subcutaneous
- Storage
- Lyophilised: −20 °C. Reconstituted: 2–8 °C, away from light.
Overview
Melanotan II is a synthetic cyclic analog of α-melanocyte-stimulating hormone (α-MSH). It activates the family of melanocortin receptors, and is studied — and widely misused — for its ability to darken skin pigmentation. It is included here for completeness in the cosmetic category, but it comes with an important caveat: it is unapproved and carries real safety concerns.
Mechanism of action
Melanotan II is a non-selective melanocortin agonist, meaning it activates several receptors at once:
- MC1R — stimulates melanin production in skin cells, the basis of its tanning effect
- MC4R — influences appetite and sexual function (its MC4R activity led to the spin-off drug bremelanotide for sexual dysfunction)
This lack of selectivity is the source of both its broad effects and its side-effect profile, which includes nausea, flushing, blood-pressure changes, and darkening of existing moles.
Common research uses
- Skin pigmentation and photoprotection research
- Melanocortin-receptor pharmacology
- Appetite and sexual-function studies (via MC4R)
Its more selective relative afamelanotide is an approved drug for a rare light-sensitivity condition, but Melanotan II itself remains experimental and is regularly the subject of health-authority warnings.
Melanotan II FAQ
What does Melanotan II do?+
It is a non-selective melanocortin receptor agonist. Activation of MC1R stimulates melanin production (tanning), while MC4R activity affects appetite and sexual function.
Is Melanotan II safe or approved?+
No. Melanotan II is not approved by any major regulator. It is associated with nausea, blood-pressure changes, darkening of moles, and other concerns, and is frequently flagged by health agencies.
How does it relate to approved melanocortin drugs?+
Its close relative afamelanotide (a more selective MC1R agonist) is approved for a rare photosensitivity disorder, but Melanotan II itself remains unapproved and experimental.
References
Related peptides
Last reviewed: 2026-06-26. Information is provided for research and educational reference only — see our disclaimer.