Peptides related to Melanotan-II primarily include other analogs of melanocyte-stimulating hormone. For instance, Melanotan-I shares a similar amino acid sequence with Melanotan-II but differs structurally; it exhibits relatively lower activity and poorer stability in vivo. Comparative studies on the structure and activity of Melanotan-I and Melanotan-II help elucidate the key factors influencing the activity and stability of this class of peptides, providing a theoretical basis for the further optimization and development of novel melanocyte-stimulating hormone analogs.

In addition, there are peptide analogs derived from modifications to the Melanotan-II structure; scientists aim to enhance activity, improve stability, or increase targeting specificity by altering amino acid sequences, modifying functional groups, or conjugating other functional molecules. Examples include incorporating cell-penetrating peptide sequences into Melanotan-II to facilitate more effective cellular entry and action, or chemically modifying specific amino acids to extend the peptide's in vivo half-life. Research into these related peptides is significant for expanding the scope of Melanotan-II applications and developing more effective therapeutic agents.