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Melanotan 2 (MT2) is a synthetic cyclic peptide modelled on alpha-melanocyte-stimulating hormone (α-MSH), the hormone that signals skin cells to produce melanin. It activates several melanocortin receptors, which is why it appears in research on pigmentation, appetite and sexual function. This overview covers its structure, what the research has looked at, how it compares to Melanotan 1 and PT-141, and where it stands legally in the UK.
What is Melanotan 2?
Melanotan 2 was developed at the University of Arizona in the late 1980s and 1990s as part of a project looking for a way to stimulate skin pigmentation and reduce skin cancer risk. Researchers shortened and cyclised α-MSH to make it more potent and longer-lasting than the natural hormone.
Key facts
- Structure: cyclic heptapeptide, Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2
- Approx. molecular weight: 1,024 Da
- Also called: MT2, MT-II, Melanotan II
- Receptor activity: non-selective agonist at MC1R, MC3R, MC4R and MC5R
How Melanotan 2 works: the melanocortin system
MT2’s effects in research all trace back to which melanocortin receptor it activates. Because it is non-selective, it hits several at once.
- MC1R: found on melanocytes; drives eumelanin (dark pigment) production.
- MC3R and MC4R: found in the brain; involved in energy balance, appetite and sexual function.
- MC5R: involved in exocrine gland function.
This lack of selectivity is the main reason MT2 was never developed into a medicine: researchers moved to compounds that target one receptor more cleanly.
What Melanotan 2 research has reported
Pigmentation
Early human studies at Arizona reported increased skin pigmentation with limited UV exposure. These were small pilot studies, not licensing trials.
Sexual function
The same studies recorded unexpected effects on sexual arousal, which led directly to the development of PT-141 (bremelanotide).
Appetite and energy balance
Through MC4R, MT2 has been used in animal studies of food intake and body weight.
Reported adverse effects
Reported effects in the literature and case reports include nausea, facial flushing, and changes to moles, which is why dermatologists and cancer charities have raised concerns.
Melanotan 1 vs Melanotan 2 vs PT-141
| Melanotan 1 | Melanotan 2 | PT-141 | |
|---|---|---|---|
| Structure | Linear, 13 amino acids | Cyclic, 7 amino acids | Cyclic, 7 amino acids (MT2 derivative) |
| Receptor focus | Mainly MC1R | MC1R, MC3R, MC4R, MC5R | Mainly MC4R and MC3R |
| Licensed? | Yes, as afamelanotide (Scenesse) for a rare light-sensitivity disorder | No | US only, as Vyleesi |
UK regulatory status
This is the part most people searching for MT2 want to know, so to be direct:
- Not a licensed medicine: Melanotan 2 has no marketing authorisation in the UK or anywhere else.
- Not a tanning product: the MHRA has repeatedly warned that selling it for tanning is illegal, as reported by Cancer Research UK.
- Research use only: PeptidesNextDay supplies MT2 solely for laboratory research and will not supply it for any personal or cosmetic use.
Our guide to whether peptides are legal in the UK covers the wider rules.
Handling MT2 research vials
- Before reconstitution: store lyophilised powder at −20°C, protected from light.
- After reconstitution: refrigerate and avoid freeze–thaw cycles.
- Diluent: see our bacteriostatic vs sterile water guide.
Melanotan 2 FAQs
Is MT2 the same as Melanotan 2?
Yes. MT2, MT-II and Melanotan II are all names for the same synthetic cyclic peptide.
What is the difference between Melanotan 1 and Melanotan 2?
Melanotan 1 (afamelanotide) is a linear peptide that is more selective for the MC1 receptor and is a licensed medicine for one rare condition. Melanotan 2 is a shorter cyclic peptide that acts on several melanocortin receptors and is not licensed anywhere.
Is Melanotan 2 legal in the UK?
Melanotan 2 is not a licensed medicine in the UK. The MHRA has warned that selling it as a tanning product is illegal. It can be supplied strictly for laboratory research.
How is PT-141 related to Melanotan 2?
PT-141 (bremelanotide) is a close derivative of Melanotan 2, developed by Palatin Technologies, with a carboxylic acid in place of the terminal amide group of MT2.
Summary
Melanotan 2 is a potent, non-selective melanocortin agonist with a research history in pigmentation, appetite and sexual function. It is not licensed and must not be sold as a tanning product. For laboratory work, PeptidesNextDay stocks Melanotan II 10mg at ≥98% purity, with batch documentation available on request.