As more doctors and patients turn to the latest weight-loss drugs, researchers are trying to figure out which drug is right for which patient—and at what point in their weight-loss journey.Key to making those decisions is how effective the drugs are and which side effects people might experience while taking them.

A new study shows that people Zepbound lost about 50% more weight than those using Wegovy. It was the first head-to-head trial of the blockbuster weight-loss medications.

Eli Lilly said on Sunday its drug Zepbound was superior to Novo Nordisk's Wegovy across five weight-loss targets such as reducing waist circumference, citing data from a head-to-head trial. The data is the first head-to-head trial comparing the wildly popular medicines,