Melanotan-1 and Melanotan-2 are usually treated as two strengths of the same thing. They are not. They are two different synthetic analogs of the same natural hormone, and the difference between them is receptor selectivity, which is why their research profiles diverge as much as they do.
Both are synthetic analogs of alpha-melanocyte-stimulating hormone (alpha-MSH), a small endogenous peptide in the melanocortin system. Melanotan-1 is the more selective, linear analog, studied primarily at the melanocortin-1 receptor (MC1R). Melanotan-2 is a cyclic, non-selective analog that also activates MC3R, MC4R, and MC5R - essentially the whole melanocortin family except the adrenal MC2R. That extra receptor coverage is the entire reason Melanotan-2 has a broader and more scrutinized research profile than Melanotan-1.
This post lays out the mechanism and selectivity difference, states the regulatory status of each compound plainly, and covers what each is examined for in the literature.
Everything below describes published pharmacology. All compounds referenced are supplied for laboratory and research use only and are not for human consumption. Nothing here is dosing guidance, administration guidance, or safety guidance.
The short version
| Melanotan-1 | Melanotan-2 | |
|---|---|---|
| Also known as | Afamelanotide, MT-1, [Nle4-D-Phe7]-alpha-MSH | MT-2, MT-II |
| Structure | Linear analog of alpha-MSH | Cyclic (ring-closed) analog of alpha-MSH |
| Receptor selectivity | MC1R-predominant | Broad: MC1R, MC3R, MC4R, MC5R (all but adrenal MC2R) |
| Parent hormone mimicked | Alpha-MSH | Alpha-MSH |
| Regulatory status | Has an approved pharmaceutical form (Scenesse) for a specific rare-disease indication | Not approved anywhere; subject of FDA consumer warnings |
| Research profile | Narrower, focused on MC1R signaling | Broader, spanning multiple melanocortin receptors |
The melanocortin system in one paragraph
Both compounds only make sense against the system they act on. The melanocortins are a family of signaling peptides derived from a single precursor protein, and they act on five known melanocortin receptors, MC1R through MC5R, each with a different distribution and role. MC1R sits on melanocytes and drives the pigment pathway. MC3R and MC4R are found largely in the central nervous system and are involved in energy balance and a range of other central functions. MC5R sits mostly in peripheral exocrine tissue. Alpha-MSH is the natural ligand most associated with MC1R. The practical question that separates any melanocortin analog from any other is how cleanly it hits one receptor versus spreading its activity across several. That is exactly the axis on which Melanotan-1 and Melanotan-2 differ.
If you want the broader background on how research peptides like these are classified and handled, what are research peptides covers the category.
What Melanotan-1 is
Melanotan-1, also called afamelanotide, is a linear analog of alpha-MSH. The parent hormone is a 13-amino-acid peptide, and the Melanotan-1 modification substitutes two residues to make the molecule more stable and more potent at its target than native alpha-MSH, while keeping the linear backbone intact.
The defining feature is selectivity. Melanotan-1 is studied primarily as an MC1R-directed analog. It does not spread its activity across the central melanocortin receptors the way its cyclic cousin does, which keeps its research profile comparatively narrow and focused on the pigment-signaling pathway that MC1R governs. That relative cleanliness at a single receptor is the whole reason afamelanotide advanced far enough to earn an approved pharmaceutical form, which is covered in the regulatory section below.
Melanotan-1 is supplied as a research compound in a 10mg vial size.
What Melanotan-2 is
Melanotan-2 is a cyclic analog of alpha-MSH. Where Melanotan-1 keeps the linear backbone, Melanotan-2 is ring-closed, a structural change that makes the molecule smaller, more rigid, and considerably less selective. It is a superpotent agonist across multiple melanocortin receptors rather than a focused MC1R analog.
That breadth is the point and the problem, depending on the research question. Melanotan-2 activates MC1R, which is why it shares the pigment-pathway lineage with Melanotan-1, but it also activates MC3R and MC4R in the central nervous system. Those central receptors are involved in functions well beyond pigmentation, which is why the Melanotan-2 literature ranges across areas that the more selective Melanotan-1 literature simply does not touch. When a source describes Melanotan-2 as having a “broader” profile, this multi-receptor activity is what they mean.
Melanotan-2 is supplied as a research compound in a 10mg vial size.
Mechanism and selectivity comparison
| Property | Melanotan-1 | Melanotan-2 |
|---|---|---|
| Backbone | Linear | Cyclic |
| Primary receptor | MC1R | MC1R plus MC3R and MC4R |
| Selectivity | Higher, MC1R-directed | Lower, multi-receptor |
| Molecular class | Alpha-MSH analog | Alpha-MSH analog |
| Central-receptor activity | Limited | Present at MC3R and MC4R |
| Research breadth | Narrower, pigment-pathway focused | Broader, spans multiple melanocortin functions |
| Relative rigidity | More flexible linear peptide | More rigid ring structure |
The single sentence version: Melanotan-1 is the selective one, Melanotan-2 is the broad one, and every difference in how the two are studied follows from that.
Regulatory status, stated plainly
This is the section most comparisons blur, so it gets stated directly, and the two facts are kept hard-separated.
Melanotan-1 / afamelanotide has an approved pharmaceutical form. Under the brand name Scenesse, afamelanotide is an approved prescription product for a specific rare-disease indication (erythropoietic protoporphyria, a rare light-sensitivity disorder). That is a regulatory fact about a specific, manufactured, prescription pharmaceutical. It is not a statement about the research compound sold here. The approved pharmaceutical form and the research chemical are different products with different manufacturing, different formulation, and different intended contexts. The existence of Scenesse says nothing about the research vial beyond the shared parent molecule.
Melanotan-2 is not approved anywhere. No regulatory agency has approved Melanotan-2 as a pharmaceutical for any indication. It has also been the subject of consumer warnings. The US FDA and several other national regulators (including the Australian TGA) have publicly warned consumers against unapproved tanning products containing Melanotan-2. That is a plainly stated regulatory fact, not a safety opinion of ours.
The takeaway for anyone comparing the two is that the regulatory status of Melanotan-1 and Melanotan-2 could hardly be more different, and it is a mistake to let the approved pharmaceutical form of afamelanotide imply anything about either research compound. Both are supplied here strictly for laboratory and research use.
What each compound is examined for
Neither research compound has an approved human indication in the form sold as a research chemical, and nothing below is a claim about outcomes.
Melanotan-1 appears in published research examining:
- MC1R binding and activation by a selective alpha-MSH analog
- Melanin synthesis and the pigment-signaling pathway downstream of MC1R
- Structure-activity relationships across linear alpha-MSH analogs
- Photoprotective signaling mechanisms in melanocyte models
- Comparative pharmacology against native alpha-MSH and against cyclic analogs
Melanotan-2 appears in published research examining:
- Multi-receptor melanocortin agonism across MC1R, MC3R, and MC4R
- Central melanocortin signaling and its role in energy balance in animal models
- Structure-activity relationships introduced by cyclization of the peptide
- MC4R pharmacology as a distinct line of central-nervous-system research
- Comparative selectivity against the more MC1R-directed linear analog
Practical differences when sourcing either compound
For a lab or a reseller, a few points are worth knowing at the point of purchase.
They are different molecules, not two strengths of one. Melanotan-1 and Melanotan-2 have different sequences, different structures (linear versus cyclic), and different molecular weights. The certificate of analysis is the document that confirms which one is in the pack. Do not treat the “-1” and “-2” as dose labels; they are separate compounds.
Both are supplied as lyophilized powder in 10-vial packs. Storage is standard cold chain for lyophilized peptides. Solvent and handling parameters are documented in the published peptide chemistry literature and are the researcher’s call, not ours to specify.
Check the COA before you check the price. You can browse the COA library without an account. Every batch is supplied to a ≥99% purity specification. Send us a COA from any independent test and we’ll issue $300 store credit regardless of what it shows.
Common questions
What is the difference between Melanotan 1 and Melanotan 2?
They are two different synthetic analogs of alpha-MSH. Melanotan-1 (afamelanotide) is a linear analog studied primarily at the MC1R receptor and is comparatively selective. Melanotan-2 is a cyclic analog that also activates MC3R and MC4R, giving it a broader, multi-receptor research profile. The difference is selectivity, not strength.
Is Melanotan 1 the same as afamelanotide?
Yes, Melanotan-1 and afamelanotide are the same molecule. Afamelanotide is the name used for the approved pharmaceutical form (Scenesse), which is a separate manufactured prescription product from the research compound sold here, even though both share the same parent molecule.
Why does Melanotan 2 have a broader research profile than Melanotan 1?
Because it is less selective. Melanotan-2 is a cyclic analog that activates MC3R and MC4R in the central nervous system in addition to MC1R, whereas Melanotan-1 is directed mainly at MC1R. Those extra central receptors are involved in functions beyond pigmentation, so the Melanotan-2 literature spans a wider range of research areas.
Is either Melanotan compound approved by regulators?
Their status is very different. Afamelanotide (Melanotan-1) has an approved pharmaceutical form, Scenesse, for a specific rare-disease indication, which is a fact about that manufactured prescription product and not about the research chemical. Melanotan-2 is not approved anywhere and has been the subject of FDA and other consumer warnings against unapproved tanning products that contain it.
Are MC1R, MC3R, and MC4R the same receptor?
No. They are three distinct melanocortin receptors with different locations and roles. MC1R is associated with the pigment pathway on melanocytes. MC3R and MC4R are found largely in the central nervous system and are involved in energy balance among other functions. The number of these receptors a given analog activates is what separates a selective compound like Melanotan-1 from a broad one like Melanotan-2.
Where to source these compounds
We manufacture both compounds and ship direct, in 10-vial packs, with no retail packaging in between. That is why the vials arrive unlabeled and why the per-vial cost is what it is.
- Melanotan-1, 10mg
- Melanotan-2, 10mg
For the broader background on how research peptides are classified and handled, see what are research peptides.
All products are supplied for laboratory and research use only. Not for human consumption, ingestion, injection, or therapeutic use.