Function
While Epitalon is reported to increase lifespan and reduce tumor incidence in animals, and to influence differentiation of neural and mesenchymal stem cells; is studied as an epigenetic regulatory peptide36, Melanotan I is approved in some regions for prevention of phototoxicity in erythropoietic protoporphyria and is studied as a skin-darkening, photoprotective peptide3444.
Mechanism
While Epitalon works as a synthetic tetrapeptide, Ala-Glu-Asp-Gly (AEDG), that has been shown to bind histones and modulate gene expression and chromatin state, with reported effects on pineal function, neurogenesis, and longevity in animal models36, Melanotan I is a linear 13-amino-acid analog of α-MSH (afamelanotide) that selectively activates MC1R on melanocytes, increasing eumelanin synthesis and providing photoprotection3444.