People taking the obesity drug Zepbound lost nearly 50% more weight than those using rival Wegovy (Ozempic) in the first head-to-head study of the blockbuster medications. Clinical trial participants who took tirzepatide, the drug sold as Zepbound, lost an average of 50 pounds over 72 weeks, while those who took semaglutide, or Wegovy, lost about 33 pounds.