Cyclic Melanocortin Peptide / α-MSH Analog
Melanotan II (MT-2) Research Peptide
Melanotan II (MT-2) is a synthetic cyclic heptapeptide analog of α-melanocyte-stimulating hormone (α-MSH), a naturally occurring 13-amino acid peptide derived from proopiomelanocortin (POMC). MT-2 was developed as a more metabolically stable, potent analog for melanocortin receptor research, incorporating Nle4 and D-Phe7 substitutions and cyclization via a lactam bridge between Asp5 and Lys10.
Compound identity
- Name
- Melanotan II
- Class
- Cyclic Melanocortin Peptide / α-MSH Analog
- CAS number
- 121062-08-6
- Molecular formula
- C₅₀H₆₉N₁₅O₉
- Also known as
- MT-2, Melanotan-2, MT II
- Sequence
- Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH₂ (cyclic 7-mer, Nle4,D-Phe7 α-MSH analog; MW 1024.18 Da)
Research context
Melanotan II (CAS 121062-08-6, MW 1024.18 Da, C₅₀H₆₉N₁₅O₉) was originally synthesized at the University of Arizona by Hruby, Hadley, and colleagues in the early 1990s as part of a program to develop metabolically stable melanocortin receptor agonists. The α-MSH native sequence (Ac-Ser-Tyr-Ser-Met-Glu-His-Phe-Arg-Trp-Gly-Lys-Pro-Val-NH₂) has a short plasma half-life; Melanotan II achieves enhanced stability and potency through Nle4 (replaces Met), D-Phe7 (resists proteolysis), and a lactam bridge cyclization between positions 5 and 10 that constrains the pharmacophore into its receptor-active conformation. The resulting compound acts as an agonist at melanocortin receptor subtypes MC1R, MC3R, MC4R, and MC5R with high affinity.
Melanocortin receptor research has investigated MT-2 in several distinct biological contexts. MC1R (expressed on melanocytes) mediates melanogenesis — eumelanin production and skin pigmentation — and is the original context for which α-MSH analogs were developed. MC3R and MC4R are expressed centrally and have been studied in preclinical models of energy homeostasis, feeding behavior, and sexual function; MC4R in particular has been characterized as a key node in hypothalamic regulation of energy balance. MC5R is expressed in exocrine glands. Preclinical studies with MT-2 in rodent models have examined these pathways. Importantly, Bremelanotide (PT-141) — a separate compound already in this catalog — is the cyclic hexapeptide metabolite of Melanotan II; PT-141 was later developed as an MC4R-focused agonist and received FDA approval for hypoactive sexual desire disorder in 2019, while MT-2 itself was never advanced to market.
As a research reagent, Melanotan II is used in melanocortin receptor pharmacology, melanogenesis research, and studies of MC3R/MC4R central signaling pathways. DMV Research supplies MT-2 as a lyophilized peptide with per-batch third-party Certificate of Analysis confirming identity by mass spectrometry and purity ≥99% by HPLC.
Frequently asked questions
What is Melanotan II (MT-2)?+
Melanotan II (MT-2, CAS 121062-08-6) is a synthetic cyclic analog of α-melanocyte-stimulating hormone (α-MSH). It acts as an agonist at melanocortin receptors MC1R, MC3R, MC4R, and MC5R. It was developed by researchers at the University of Arizona as a metabolically stable probe for melanocortin receptor pharmacology, incorporating Nle4 and D-Phe7 substitutions and lactam cyclization to increase receptor binding affinity and metabolic stability relative to native α-MSH.
What is the difference between Melanotan II and PT-141 (Bremelanotide)?+
Melanotan II (MT-2) is a cyclic heptapeptide (7 residues, MW 1024 Da). PT-141 (Bremelanotide) is a cyclic hexapeptide (6 residues) that is a metabolite of MT-2 — formed by the in vivo removal of the C-terminal amide group. PT-141 was separately developed as an MC4R-focused agonist and received FDA approval in 2019 (brand name Vyleesi) for premenopausal women with hypoactive sexual desire disorder. MT-2 was not itself approved. The two compounds have related but distinct receptor affinity profiles and pharmacokinetic properties.
Which melanocortin receptors does MT-2 act on?+
Melanotan II is a non-selective melanocortin agonist with affinity for MC1R, MC3R, MC4R, and MC5R. MC1R mediates melanogenesis (skin pigmentation) on melanocytes. MC3R and MC4R are expressed in the central nervous system and have been studied in the context of energy homeostasis and other hypothalamic signaling pathways in preclinical models. MC5R is expressed in exocrine glands. The lack of selectivity across these subtypes is a distinguishing characteristic of MT-2 as a research reagent compared to more subtype-selective probes.
Is Melanotan II approved for human use?+
No. Melanotan II is not FDA-approved or approved by any regulatory body for human use. It was investigated in early clinical research but was never brought to market. As supplied by DMV Research, MT-2 is a research peptide for in-vitro and pre-clinical laboratory research purposes only. Not for human consumption.
Research use only
All products are intended for laboratory and research use only (RUO) and are not for human consumption, ingestion, or any in-vivo use.
The statements on this page have not been evaluated by the FDA. Melanotan II is not intended to diagnose, treat, cure, or prevent any disease. Content is provided for laboratory research reference only.