In one study, the average weight loss for a group taking a higher dose (32 mg) of naltrexone plus bupropion for about a year was 6.1% while for a lower dose (16 mg) it was 5%. (People taking a placebo had an average weight loss of 1.3%.) However, only half the participants who started the trial actually finished it.

CNN: Combo of old drugs offers new hope in obesity fight