MT-1 vs MT-2: Melanotan Comparison for Research
Peptide comparison
Melanotan 1 vs Melanotan 2.
Both peptides come from the same University of Arizona research program in the 1980s, but they were designed for different purposes. MT-1 is selective for MC1R and FDA-approved for erythropoietic protoporphyria. MT-2 is a pan-melanocortin agonist used primarily in research. Here is the practical difference.
Bottom line
MT-1 (afamelanotide) is more selective for MC1R, has a narrower side-effect profile, and has FDA approval. MT-2 is broader (activates MC1R, MC3R, MC4R, MC5R), produces more systemic effects beyond pigmentation, and is research-only. For clean pigmentation research, MT-1. For broader melanocortin pharmacology research, MT-2.
Side-by-side comparison
| Melanotan 1 (MT-1) | Melanotan 2 (MT-2) |
Deep dive: Melanotan 1 (MT-1)
MT-1 (afamelanotide, Scenesse) is a 13-amino-acid linear analogue of alpha-melanocyte-stimulating hormone with relative selectivity for the MC1R receptor. MC1R is the receptor primarily responsible for pigmentation effects, so MT-1 produces pigmentation outcomes with much less interference from the other melanocortin receptors.
The compound has FDA approval (2019) for treatment of erythropoietic protoporphyria, a rare genetic condition causing severe sun sensitivity. Clinical implementation uses a sustained-release subcutaneous implant providing approximately 60 days of exposure per implant. Research-grade MT-1 uses injection-based administration.
Side-effect profile is comparatively mild because MC3R, MC4R, and MC5R are not significantly activated. Initial nausea is the most common observation in research protocols.
Read the full Melanotan 1 (MT-1) research guide →
Deep dive: Melanotan 2 (MT-2)
MT-2 is a 7-amino-acid cyclic analogue of alpha-MSH with broad activity across all five melanocortin receptors. The cyclization (amide bridge between aspartic acid and lysine residues) provides metabolic stability that the native linear alpha-MSH lacks.
The pan-receptor profile means MT-2 produces effects beyond pigmentation: MC4R activation contributes to appetite suppression and sexual function effects, MC3R and MC5R activation produce more diffuse metabolic and exocrine effects. These broader effects make MT-2 useful for general melanocortin pharmacology research but produce a more pronounced side-effect profile than MT-1.
MT-2 has no FDA approval anywhere and remains a research-only compound. Most published research uses injection-based administration with titration from low doses to manage initial nausea and flushing.
Read the full Melanotan 2 (MT-2) research guide →
Which should you research?
If your research is specifically about pigmentation, photoprotection, or MC1R pharmacology, MT-1 (afamelanotide) is the more focused tool. The narrower receptor profile means the pigmentation effects can be studied without confounding from other melanocortin receptors.
If your research extends beyond pigmentation into energy homeostasis, sexual function, or general melanocortin receptor pharmacology, MT-2 captures the broader profile and is the more useful research tool. The trade-off is more pronounced side effects across the dosing window.
For pharmacology research that explicitly compares selective versus pan-receptor activity, both peptides used side-by-side in matched protocols characterize the differential contribution of MC1R alone versus the full melanocortin receptor family.
Frequently asked questions
Is MT-1 the same as afamelanotide?
Yes. MT-1 and afamelanotide are the same molecule. Afamelanotide is the development/clinical name; MT-1 is the research-community shorthand. The FDA-approved product Scenesse uses afamelanotide in a sustained-release subcutaneous implant.
Why does MT-2 cause more side effects?
MT-2’s pan-melanocortin profile activates MC3R, MC4R, and MC5R in addition to MC1R. MC4R activation produces appetite suppression, blood pressure changes, and sexual function effects. MC3R and MC5R add more diffuse metabolic effects. MT-1’s MC1R selectivity avoids most of these collateral effects.
Which one produces more pigmentation?
Both produce pigmentation through MC1R activation. MT-2 may produce slightly faster pigmentation effects due to higher MC1R potency and the cyclic stability, but MT-1’s accumulating effect over 4-12 weeks reaches similar pigmentation outcomes in matched research protocols.
Can MT-1 be used at higher research doses to mimic MT-2 effects?
No. MT-1’s receptor selectivity means even at high doses it produces primarily pigmentation effects. The broader profile of MT-2 comes from receptor activation that MT-1 simply does not engage at relevant concentrations.
Why does only MT-1 have FDA approval?
MT-1’s narrower receptor profile produced an acceptable safety profile for clinical development. The development program for erythropoietic protoporphyria (a rare genetic condition causing severe sun sensitivity) was sufficient for FDA approval based on the photoprotective effect of induced pigmentation. MT-2’s broader effects across multiple receptors complicate clinical development paths.
References
- Lane AM, Wiedemann J, Riester P, et al. (2020). Afamelanotide for Erythropoietic Protoporphyria. View source
- Hadley ME, Hruby VJ, Jiang J, et al. (1989). Discovery and development of novel melanogenic drugs. View source
- Wessells H, Levine N, Hadley ME, et al. (2000). Melanocortin receptor agonists, penile erection, and sexual motivation: human studies with Melanotan II. View source
Reviewed by
The Aeternum Labs Research Team
Compounds, COAs, and protocol design
The Aeternum Labs research team verifies every batch in our library against published purity and identity standards. Comparison guides summarize publicly available scientific literature and are reviewed for accuracy by team members trained in peptide biochemistry.
Research Disclaimer. All compounds discussed in this article are sold by Aeternum Labs for in vitro laboratory research purposes only. They are not intended for human or animal consumption, diagnosis, treatment, or prevention of any disease or condition. Information presented is summarized from publicly available scientific literature and should not be construed as medical advice.