Melanotan II
Also known as: MT-II · MT2
A cyclic heptapeptide analogue of alpha-MSH acting non-selectively across several melanocortin receptor subtypes. Associated with documented safety concerns in unsupervised use.
Development status: Preclinical — laboratory and animal studies only
Identifiers and molecular characteristics
- CAS number
- Not verified
- Molecular formula
- Not verified
- Molecular mass
- Not verified
- Amino-acid sequence
- Not verified
- PubChem CID
- Not verified
Identifiers are published only with a source and a check date. Fields marked “not verified” have not yet been confirmed against a primary source — we show the gap rather than an unchecked figure. Always confirm against the certificate of analysis for the specific lot you hold.
Biological targets
- MC1R
- MC3R
- MC4R
- MC5R
Mechanism of action
A cyclic lactam-bridged analogue of alpha-melanocyte-stimulating hormone. Its lack of receptor subtype selectivity explains the breadth of reported effects: MC1R relates to pigmentation, MC4R to appetite and sexual function.
Research evidence and its limits
Early pharmacology plus a substantial case-report literature documenting adverse events associated with unregulated use, including reports concerning changes in melanocytic lesions.
Safety considerations
No regulatory authority has assessed this compound as safe or effective for any human indication. The published record is predominantly laboratory and animal work, which does not establish human safety. Supplied and discussed here strictly as a laboratory research material. Not a medicine, not for human or veterinary administration, and nothing on this page should be read as a dosing, treatment or safety recommendation.
Analytical identification and quality testing
Identity by high-resolution mass spectrometry against the expected mass, purity by RP-HPLC with UV detection. Tandem MS sequencing or peptide mapping gives stronger identity evidence than mass alone.
Regulatory status
Not approved in any major jurisdiction. Several regulators have issued public warnings about unregulated supply.
Frequently asked questions
Is Melanotan II the same as afamelanotide?
No. Afamelanotide is a different, MC1R-selective analogue that has been through regulatory review for a rare indication. Melanotan II is non-selective and unapproved.
References
Related compounds
PT-141 (bremelanotide)
A melanocortin receptor agonist, structurally related to Melanotan II, which has received marketing authorisation in at least one jurisdiction for a specific indication.
Afamelanotide
An MC1R-selective alpha-MSH analogue approved for a rare photosensitivity disorder. Distinct from Melanotan II despite the shared informal naming.
Entry last reviewed 2026-10-11. Regulatory status and scientific understanding change; verify against primary sources before relying on anything here.