What is bremelanotide?

A melanocortin receptor agonist that received its first regulatory approval in 2019, for hypoactive sexual desire disorder.

How does it relate to MT-2?

Both derive from alpha-MSH pharmacology. Bremelanotide went through regulatory assessment to an approved indication; MT-2 did not.

How many melanocortin medicines are approved?

Three are discussed on this site — afamelanotide, setmelanotide and bremelanotide. MT-2 is not among them.

MT-2 (Melanotan II)

A Third Approved Melanocortin Medicine

JMWritten & reviewed by Jack Muncaster · Founder, UK PeptidesLast reviewed 2026-08-233 cited sources

Bremelanotide is a melanocortin receptor agonist that received its first approval in 2019, reported by Dhillon in Drugs that year. It is a further example of an alpha-MSH-derived compound taken through regulatory assessment to an approved indication.

Key facts

First approval: 2019
Approval report: Dhillon 2019, Drugs (PMID 31429064)
Class: Melanocortin receptor agonist
Indication: Hypoactive sexual desire disorder
Second review: Mayer 2020 (PMID 31893927)
Relation to MT-2: Same hormone family, different compound

What it is

A melanocortin receptor agonist derived from the same alpha-MSH pharmacology that produced the other compounds discussed in this category. Dhillon reported its first approval in Drugs in 2019, and Mayer reviewed it in the Annals of Pharmacotherapy in 2020 for hypoactive sexual desire disorder. That indication is stated here as a regulatory fact and not elaborated on.

Why its existence is relevant to this category

It demonstrates, for a third time, that alpha-MSH-derived compounds can be developed to approval. Afamelanotide holds an approval for photoprotection in a rare condition. Setmelanotide holds one for rare genetic obesity. Bremelanotide holds one in a further indication. The pharmacology is capable of producing licensed medicines.

Research material referenced

MT-2 10mg — third-party HPLC tested

View — £19.99

Which sharpens the point about MT-2

MT-2 is not among them. It is not that melanocortin compounds cannot be approved — three have been. It is that this particular one was never taken through the process, and its absence from that list reflects development history rather than any barrier inherent to the hormone family.

What an approval required in each case

A defined indication, clinical trials in that population, a safety database, a label with contraindications, and ongoing pharmacovigilance. Three separate compounds accumulated all of that. MT-2 has none of it, and no registered clinical programme exists to produce any.

Why the receptor selectivity question runs underneath

Each approved compound has a defined receptor profile matched to its indication. A compound described as non-selective across a receptor family whose members govern pigmentation, energy balance and exocrine function is a different proposition from one engineered and assessed for a specific target.

The boundary

Bremelanotide is a licensed medicine prescribed and monitored clinically. Nothing supplied on this site is bremelanotide, is related to it, or is an alternative to it or to any licensed medicine. MT-2 holds no marketing authorisation in any jurisdiction.

Extended research context

The MT-2 (Melanotan II) deep dive

Deep dive: the identifier collision that points the wrong way

This site has now found several plausible-looking identifiers that resolve to the wrong molecule. A PubChem record for tirzepatide cited as retatrutide. Thymosin beta-4's CAS quoted as TB-500's. An unrelated organic acid returned for KPV. This one is the most consequential of the set, and the reason is direction. Searching PubChem for melanotan returns CID 16197727 - afamelanotide, at 1,646.8 Da for C78H111N21O19. That is Melanotan I, a linear thirteen-residue peptide, and it is an APPROVED MEDICINE, marketed as Scenesse for erythropoietic protoporphyria. Melanotan II is CID 92432: cyclic, seven residues, 1024.2 Da, 622 Da lighter, and assessed by no regulator anywhere. So the wrong record does not merely mislead about mass. It resolves from an unlicensed compound toward a licensed one, and the sequential naming - I and II - makes them look like versions of a single product rather than the structurally distinct compounds they are. Anyone verifying a certificate by searching the bare name lands on an approved drug's record and may never notice which compound it names.

Deep dive: four stability features in seven residues

PubChem's IUPAC name for CID 92432 is unusually complete and reads as a full specification: N-acetyl-L-norleucyl-L-alpha-aspartyl-L-histidyl-D-phenylalanyl-L-arginyl-L-tryptophyl-L-lysinamide, cyclic (2-7)-peptide. Unpack it and there are four independent protease-resistance features in a molecule of seven residues. A lactam bridge joins the aspartate side chain at position 2 to the lysine side chain at position 7, closing the ring - which both locks conformation for receptor engagement and eliminates the free termini exopeptidases require. Position 4 is D-phenylalanine, the mirror image of the natural form, and proteases are stereospecific enough that they largely cannot process it. The N-terminus is acetylated and the C-terminus amidated, capping both ends. And position 1 is norleucine, which is not among the twenty proteinogenic amino acids at all - so even setting aside the cyclisation and the D residue, this peptide could never have been a gene product. It is a fully synthetic construction rather than a modified natural sequence, and it is among the most chemically robust compounds in this catalogue as a direct result.

Deep dive: why the safety literature is included rather than omitted

There is a published dermatological literature here, and the editorial choice was to state it. Reid and colleagues documented atypical melanocytic naevi following melanotan injection in the Irish Medical Journal in 2013. Eijmael and colleagues published a risk review in the Nederlands Tijdschrift voor Geneeskunde in 2022 - a national medical journal considering the topic worth addressing directly. Case reports have a real limitation: they establish an observation without a denominator, so they cannot establish causation or incidence, which is the same constraint that applies to pharmacovigilance disproportionality signals. But that limitation cuts both ways. A case report is not proof of harm and it is not dismissible either. What makes the absence of better data significant here is that no regulator has assessed this compound - so there is no label, no contraindications, no adverse event reporting requirement and no monitoring framework. The information that would normally exist for an injectable product simply does not, and what is available instead is what individual clinicians chose to publish after seeing something. Presenting the compound without that context would give an incomplete picture of what is actually known.

Research applications

▸Melanocortin receptor pharmacology and selectivity research
▸Cyclic peptide and lactam bridge design studies
▸D-amino acid substitution and protease resistance research
▸Structure-activity work on constrained peptide analogues
▸Comparative work on alpha-MSH derivatives
▸Analytical method development for cyclic peptides

Handling checklist

✓Verify against CID 92432, 1024.2 Da, C50H69N15O9, CAS 121062-08-6
✓Never verify by searching 'melanotan' alone - that returns afamelanotide at 1,646.8 Da
✓Require stereochemistry on the certificate - D-Phe4 is not detectable by mass
✓Protect from light; tryptophan at position 6 is photochemically reactive
✓Store lyophilised, cold, dry and dark
✓Expect no disulfide or oxidation satellites - no cysteine, no methionine
✓Quantification at 280 nm is available thanks to the tryptophan

Common research-handling mistakes

Learnt from thousands of researcher orders across our UK labs.

✗ Searching PubChem for 'melanotan' to verify identity

Fix: That returns CID 16197727, afamelanotide, at 1,646.8 Da - an approved medicine and a different molecule. Use CID 92432 or search Melanotan II with the numeral.

✗ Treating Melanotan I and II as versions of one compound

Fix: They differ by 622 Da, by six residues, and by whether the peptide is cyclic or linear. Only Melanotan I has been assessed by regulators.

✗ Reading afamelanotide's approval as covering MT-2

Fix: Different molecule, different structure, different evidence, different assessment. Nothing transfers.

✗ Accepting a sequence written without stereochemistry

Fix: L- and D-phenylalanine have identical mass. A peptide with the L form at position 4 is a different compound that mass spectrometry cannot distinguish.

✗ Assuming a non-selective agonist affects only its intended receptor

Fix: Five melanocortin receptors share binding surfaces across different tissues. Engagement elsewhere is the same pharmacology in another place, not a side reaction.

Continue researching

Peer-reviewed guides, comparators and matched reference materials.

Frequently asked questions

What is bremelanotide?: A melanocortin receptor agonist that received its first regulatory approval in 2019, for hypoactive sexual desire disorder.
How does it relate to MT-2?: Both derive from alpha-MSH pharmacology. Bremelanotide went through regulatory assessment to an approved indication; MT-2 did not.
How many melanocortin medicines are approved?: Three are discussed on this site — afamelanotide, setmelanotide and bremelanotide. MT-2 is not among them.

Primary sources & clinical trials

Peer-reviewed research and registered trials from PubMed, ClinicalTrials.gov, PubChem, FDA and NIH. All links open in a new tab and point to the primary source, so every claim can be verified at origin.

Written and reviewed by

Jack Muncaster · Founder, UK Peptides

Jack founded UK Peptides in Manchester after repeatedly receiving research compounds with missing or recycled paperwork. He is responsible for supplier selection, batch release decisions and the content published in this research library. Every article here is sourced to primary literature and every product page to a signed third-party certificate.

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