Each of the five anti-obesity agents currently approved in the United States including orlistat, lorcaserin, naltrexone-bupropion, phentermine-topiramate, and liraglutide can enhance weight loss with a variety of mechanisms, and have positive effects on related comorbidities. There is significant 1-year weight loss for these drugs in comparison with placebo. In a comparative trial, weight loss ranged from 2.6 kg with orlistat to 8.8 kg with phentermine-topiramate.