The present invention provides methods of treating obesity, eating disorders, and sexual dysfunction. The methods comprise administering to a mammalian host suffering from obesity, an eating disorder, or sexual dysfunction an effective dose of a compound of the invention. Also provided are methods of potentiating the effect of an MC4 receptor agonist in a mammalian host. In some cases the methods comprise administering to the host a compound that lowers the EC
50
of the agonist. In other cases the methods comprise administering to the host a compound that increases the maximum effect of the agonist.