Overview
Following subcutaneous or intramuscular injection, Melanotan I achieves peak plasma concentrations within 30–60 minutes (Tmax ~0.5–1 h). Its plasma half-life is approximately 1–2 hours, but the downstream biological effect on MITF-driven transcription and melanin synthesis persists far beyond plasma clearance — resulting in a prolonged pigmentary response (days to weeks). In the clinical EPP application, a subcutaneous biodegradable poly(lactic-co-glycolic acid) implant releasing ~0.27 mg/day maintains trough plasma concentrations that continuously saturate MC1R, preventing the painful phototoxic crises triggered by protoporphyrin IX photoactivation.
Proposed mechanism
Melanotan I binds to and activates melanocortin receptors, principally MC1R on melanocytes, triggering the cAMP–protein kinase A signaling cascade that upregulates tyrosinase activity and eumelanin synthesis. Increased eumelanin in keratinocytes provides photoprotective pigmentation by absorbing and scattering UV radiation. MC1R activation also suppresses NF-κB-mediated inflammatory cytokine production, contributing to the compound's anti-inflammatory properties.
What the evidence supports
Randomised controlled trial data in humans exists and supports use in specific contexts.
Graded Clinical
Findings supported by randomised, controlled trials in humans, with pre-registered endpoints and published results.
Key citations
Representative primary sources, including results that did not favour the compound.
- [1]
Afamelanotide for Erythropoietic Protoporphyria (Phase III RCT)
· New England Journal of Medicine — Langendonk JG et al., NEJM 373:48–59 · 2015
- [2]
MC1R biology and the pigmentary response to alpha-MSH
· Pigment Cell Research — Garcia-Borron JC et al. · 2006
- [3]
FDA Approval of Scenesse (afamelanotide) NDA 210797
· FDA.gov Center for Drug Evaluation and Research · 2019
- [4]
Anti-inflammatory effects of alpha-MSH analogues via MC1R
· Journal of Leukocyte Biology — Luger TA et al. · 2010
Citation records in this build are illustrative placeholders for the design.
Reference information for research purposes. Not medical advice, and not a recommendation to use any compound. Many entries describe substances that are not approved for human use.