MT-1 (Melanotan I)
High EvidenceA melanocortin receptor agonist FDA-approved (in Europe) for preventing phototoxicity in erythropoietic protoporphyria.
What It Is
Melanotan I (afamelanotide) is a synthetic 13-amino acid analog of alpha-melanocyte-stimulating hormone (α-MSH) that selectively targets the melanocortin 1 receptor (MC1R) to stimulate melanogenesis. Unlike Melanotan II (which is non-selective across MC1R–MC5R), MT-1's selectivity for MC1R provides a tanning effect without the sexual side effects, appetite changes, or broader hormonal disruption associated with MC4R activation. Afamelanotide is the only melanocortin peptide to achieve regulatory approval: it is FDA-approved (brand name Scenesse) for the prevention of phototoxicity in adult patients with erythropoietic protoporphyria (EPP), a rare genetic condition causing severe pain upon sun exposure. The drug is administered as a subcutaneous implant that releases afamelanotide over approximately 60 days. In Phase III trials for EPP, afamelanotide significantly increased the duration of sun exposure patients could tolerate without pain compared to placebo. Research is exploring additional applications including photoprotection for vitiligo patients, prevention of UV-related skin damage, and potential use in polymorphous light eruption (PMLE). A 2024 pilot study examined afamelanotide combined with narrowband UVB phototherapy for vitiligo repigmentation, with promising preliminary results. MT-1/afamelanotide is a prescription medication for EPP and is not available for cosmetic tanning purposes.
Why Researchers Study It
MT-1 (afamelanotide) is one of the few melanocortin peptides to reach regulatory approval, providing a validated proof-of-concept for melanocortin receptor-targeted therapeutics. Its selectivity for MC1R over other melanocortin receptors makes it a cleaner pharmacological tool than MT-2, with fewer off-target effects.
Proposed Mechanisms
- Selective agonist of the melanocortin 1 receptor (MC1R) on melanocytes
- Stimulates eumelanin synthesis, providing photoprotection independent of UV exposure
- Longer half-life than endogenous α-MSH due to amino acid substitutions
- Photoprotective mechanism distinct from sunscreens — increases intrinsic skin defense
Evidence Snapshot
Commonly Discussed Benefits
Safety & Cautions
- Approved in Europe for EPP; not FDA-approved in the US for any indication
- May cause nausea, facial flushing, and headache
- Unregulated versions carry quality and safety risks
- Should only be used under medical supervision
Comparisons
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Citations
- [1] Langendonk JG. et al. — Afamelanotide for erythropoietic protoporphyria. N Engl J Med. 2015 PubMed
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Related Peptides
PT-141
High EvidenceA melanocortin receptor agonist FDA-approved for hypoactive sexual desire disorder in premenopausal women.
MT-2 (Melanotan II)
Medium EvidenceA melanocortin receptor agonist studied for tanning, sexual function, and appetite suppression.