What's on the label is the measured result — net peptide mass, not gross powder weight, plus RP-HPLC purity, on a lot-numbered COA for every batch.
Net peptide mass and RP-HPLC purity — a lot-numbered COA for every batch.
Net peptide mass + HPLC purity, per lot.
PCAC will review 7 peptides for the 503A bulks list, BPC-157, KPV, TB-500, MOTS-c, Emideltide, Semax, Epitalon. Read our briefing →
PCAC will review 7 peptides for the 503A bulks list. Read →
FDA PCAC reviews 7 peptides in July. Read →
α-MSH analog · approved for erythropoietic protoporphyria
PeptideXpo buyer fit
This PeptideXpo page is intentionally positioned for distributors, OEM buyers, and procurement teams comparing Melanotan I (Afamelanotide) inside a wider peptide catalog. It is not trying to be the deepest single-molecule monograph; the differentiated intent is assortment planning, export-ready documentation, fill-size comparison, and whether this SKU belongs in a broader buyer program.
Overview
Melanotan I (Afamelanotide, brand name Scenesse) is a linear 13-amino-acid synthetic analog of native α-MSH with two engineered substitutions ([Nle4, D-Phe7]) that confer both protease resistance and improved MC1R selectivity over the broader melanocortin-receptor family. The MC1R selectivity is the key pharmacological feature that distinguishes Melanotan I from Melanotan II: MC1R drives pigmentation effects on melanocytes without the off-target CNS, cardiovascular, and sexual-function effects that come from MC3R/MC4R/MC5R activation. This receptor selectivity was what allowed Melanotan I to advance through clinical development to FDA, EMA, and TGA approval as a prescription drug for erythropoietic protoporphyria (EPP), providing photoprotection in patients with the rare metabolic disorder. PeptideXpo supplies Melanotan I (Afamelanotide) as a lyophilized powder at ≥99.0% HPLC purity. The linear 13-residue sequence with non-natural residues (Nle4 and D-Phe7) is at the upper-middle range for SPPS, the analytical packet covers peak-integration HPLC, mass spec confirming the modified mass, and on-request sequence verification by LC-MS/MS. As an approved prescription drug in multiple jurisdictions, buyers should reference the local approved product (Scenesse implant) for clinical use; bulk Afamelanotide is supplied for research and qualified compounding workflows only.
Who buys this, and why
Cosmetic-peptide buyers fall into two groups: established beauty / med-aesthetic brands extending an existing line, and OEM clients building a private-label catalog from scratch. The first group usually wants bulk active plus stability data in their existing carrier matrix; the second usually wants a finished formulation under their label. Both need INCI naming verified, regulator-specific safety files (CPNP for EU, FDA OTC monograph for US where relevant), and packaging-compatibility data.
Primary buyer fit: academic and contract research laboratories and 503A / 503B compounding pharmacies.
Specifications
Documentation available on request
Regulatory note
Approved as a prescription drug (Scenesse) in several jurisdictions for erythropoietic protoporphyria. Sold only to qualified buyers with appropriate licensing in their jurisdiction; clinical use should reference the local approved finished product rather than bulk active.
Frequently asked questions
The difference comes down to receptor selectivity and side-effect profile. Melanotan I (Afamelanotide) is selective for MC1R, which drives pigmentation effects on melanocytes without the off-target effects on MC3R/MC4R/MC5R that would produce CNS, cardiovascular, and sexual-function effects. This clean selectivity allowed clinical development to advance through FDA, EMA, and TGA approval for erythropoietic protoporphyria (EPP) under the brand Scenesse. Melanotan II is non-selective across the melanocortin receptor family, producing the broader effect profile that includes the unwanted off-target activities, which is why MT-II remains regulated as a research-only compound in most major jurisdictions.
EPP is a rare metabolic disorder caused by deficiency in ferrochelatase, the enzyme that inserts iron into protoporphyrin IX during heme synthesis. The unconverted protoporphyrin accumulates in red blood cells, plasma, and skin, where it absorbs visible-light wavelengths and produces severe photosensitivity reactions, patients with EPP can experience burning pain within minutes of sun exposure. Afamelanotide drives MC1R-mediated melanin production in skin, increasing the photoprotective barrier and substantially extending the time-to-symptoms exposure window. The MC1R selectivity is essential because broader melanocortin agonism would add cardiovascular and CNS effects that are unacceptable in a chronic-dosing photoprotection product. Afamelanotide as Scenesse is approved for EPP in the US (FDA, 2019), EU (EMA, 2014), and Australia (TGA).
Related peptides
