Function
While Melanotan I is approved in some regions for prevention of phototoxicity in erythropoietic protoporphyria and is studied as a skin-darkening, photoprotective peptide3444, Thymosin Alpha-1 is clinically used in some countries as an immunomodulator for chronic hepatitis B/C and as an adjuvant in cancer therapy, enhancing cell-mediated immunity41487.
Mechanism
While Melanotan I works as a linear 13-amino-acid analog of α-MSH (afamelanotide) that selectively activates MC1R on melanocytes, increasing eumelanin synthesis and providing photoprotection3444, Thymosin Alpha-1 is a 28-amino-acid thymic peptide fragment of prothymosin alpha that activates dendritic cells and T cells primarily via TLR9/MyD88/NF-κB signaling, enhancing Th1 responses and NK-cell cytotoxicity414.
Length and Sequence
Melanotan I is 13 amino acids long, whereas Thymosin Alpha-1 is longer as it has a length of 28 amino acids. Melanotan I is made up of a sequence of Serine, Tyrosine, Serine, Nle, Glutamic acid, Histidine, Phenylalanine, Arginine, Tryptophan, Glycine, Lysine, Proline, Valine. Thymosin Alpha-1 is made up of a sequence of Serine, Aspartic acid, Alanine, Alanine, Valine, Aspartic acid, Threonine, Serine, Serine, Glutamic acid, Isoleucine, Threonine, Threonine, Lysine, Aspartic acid, Leucine, Lysine, Glutamic acid, Lysine, Lysine, Glutamic acid, Valine, Valine, Glutamic acid, Glutamic acid, Alanine, Glutamic acid, Asparagine.