MT-1 · MT1 · Melanotan I · Afamelanotide · Scenesse
MT-I (Melanotan I, INN: afamelanotide, brand: Scenesse) is a synthetic linear analog of α-melanocyte-stimulating hormone (α-MSH) - a 13-amino-acid linear peptide with substitutions ([Nle4, D-Phe7]-α-MSH) that confer high MC1R receptor selectivity and increased metabolic stability. FDA-approved (October 2019) and EMA-approved as Scenesse for the prevention of phototoxicity in adult patients with erythropoietic protoporphyria (EPP) - a rare genetic disease causing severe sunlight-induced skin pain.
Evening. NOTE - this Quick Start describes the OFF-LABEL injectable protocol only. The FDA-approved product is different in every respect: SCENESSE (afamelanotide) is a 16 mg implant placed subcutaneously by a clinician roughly every 2 months, licensed only for erythropoietic protoporphyria. Do not read the implant dose as an injection dose. Photograph existing moles at baseline and recheck periodically.
Start here. Every protocol below is ordered lowest-first. Begin at the smallest effective dose, hold about a week to assess tolerance, and step up only if needed.
MT-I binds the melanocortin-1 receptor (MC1R) on melanocytes in skin and hair follicles, activating the cAMP/PKA cascade. PKA phosphorylates the microphthalmia-associated transcription factor (MITF), which upregulates expression of melanogenesis enzymes (tyrosinase, TRP-1, TRP-2). Net effect: increased eumelanin (the photoprotective black/brown melanin) production and pigment transfer to keratinocytes.
MT-I has 10-100x higher affinity for MC1R than for the other melanocortin receptors (MC3R, MC4R, MC5R). This selectivity contrasts with MT-II's broader profile and explains MT-I's restricted side-effect profile (no significant appetite, libido, or erection effects).
Activation of MC1R favors eumelanin synthesis over pheomelanin - eumelanin is the photoprotective pigment that absorbs UV radiation. The mechanism is therapeutically meaningful for EPP patients, who lack effective photoprotection due to porphyrin accumulation.
Linear 13-amino-acid analog with [Nle4, D-Phe7] substitutions (replacing native Met4 with norleucine and Phe7 with D-phenylalanine). These substitutions resist enzymatic degradation and extend the molecule's bioavailability vs native α-MSH.
FDA-approved as Scenesse implant - 16 mg sustained-release implant placed subcutaneously every 2 months. Provides sustained α-MSH receptor activation over weeks. Off-label use is via daily SubQ injection of reconstituted lyophilized peptide.
Linear peptide without methionine or cysteine residues - chemistry-compatible with copper-conjugated peptides like GHK-Cu. No disulfide bonds means no copper-driven oxidation concerns.
Week 1-2: existing pigmented spots darken; early tan develops with UV exposure.
Week 2-4: deeper, more even tan develops with continued UV exposure.
Week 4+: tan stabilizes; maintenance dosing 1-2x weekly sustains. Without UV exposure, MT-I produces little visible effect.
Each reference below was re-fetched from its PubMed record, and the quoted sentence was confirmed to appear in that abstract and to support the claim it sits under. Follow any of them to read the source.
Evidence boundary from the checked abstract: Melanotan I leads to the activation of dysplastic nevi.
Melanotan I leads to the activation of dysplastic nevi.
Evidence scope. This entry supports only the exact statement quoted from the live abstract; it does not independently verify OnePin's displayed dose, route, frequency, formulation, population, or broader mechanism.
Claims we could not support
No abstract we checked supports these for this molecule at this route. That is not the same as saying they are false — it marks where the evidence is missing.
Dose/route: 0.5 mg (off-label injection); Subcutaneous (SubQ) injection; Daily. No checked live PubMed abstract verified this exact displayed dose, route, and frequency for the same molecule/formulation and relevant population.
Primary safety claim: No primary safety text present in source JSON. No checked live PubMed abstract directly verified this source-JSON safety claim at the displayed formulation, route, and regimen.
Native peptide ~24-48 hours functional (Scenesse implant provides sustained release over weeks)
Post-injection (SubQ)
Days to weeks (sustained melanin production beyond plasma clearance)
subQ ~70%
Days to weeks - melanin production cascade continues after peptide clears
Renal/proteolysis
Storage. Lyophilized vial: refrigerate (2-8°C / 36-46°F) or freeze (-20°C) for long-term storage. After reconstitution with bacteriostatic water: refrigerate, use within 21-28 days. LIGHT-SENSITIVE - protect from light especially after reconstitution. Discard if cloudy, discolored, or contains particulates. Scenesse implant: clinician-stored per manufacturer specifications.
FDA-approved as Scenesse (afamelanotide, 16 mg implant) since October 2019 for adult patients with erythropoietic protoporphyria (EPP). EMA-approved 2014 for same indication. Outside EPP, off-label tanning use is unapproved. Sale of MT-I as a research peptide for off-label tanning use is technically prohibited by FDA but enforcement is variable. Some sport organizations prohibit melanocortin agonists under performance-enhancement rules. Pregnancy category data inadequate.
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