Melanocortin receptor-specific peptides with a C-terminal naphthylalanine of the formula:where R4, R7, R9, R11, R18, R20, R21a, R21b, R21c and R22 are as defined in the claims, compositions and formulations including the peptides of the foregoing formula or salts thereof, and methods of preventing, ameliorating or treating melanocortin receptor-mediated or responsive diseases, indications, conditions and syndromes.