The identification of a highly efficacious anti-obesity agent remains an illusive goal. While many avenues of investigation have been pursued, none of the existing compounds claim much more than a 10% reduction in weight in humans (over a one year period with diet and exercise). Nonetheless, the potential reward for fulfilling this unmet medical need has kept interest levels high in the research community. The recent explosion of genetic information has identified numerous potential targets for drug screening. The melanocortin-4 receptor is a promising target and is currently being intensively investigated by many companies and academic research groups.