How Ozempic, Wegovy, and Mounjaro compare on weight loss effectiveness

The booming market for weight-loss drugs is expected to reach $100 billion in 2030, according to Goldman Sachs, and so far the field has few players.

First to the market was Novo Nordisk, with Wegovy. Demand for the injectable medication is through the roof, with sales spiking 734% in the last quarter compared to the previous year, triggering widespread supply shortages.

Now a much-anticipated rival, Zepbound by Eli Lilly, has won US Food and Drug Administration (FDA) approval, providing another option for eager consumers to compare efficacy and price. Meanwhile, UK regulators have approved Eli Lilly’s Mounjaro for weight-loss management use.

Note, Wegovy and Zepbound are the only two drugs approved to treat obesity in the US. Novo Nordisk’s Ozempic and Eli Lilly’s Mounjaro are approved in the US and UK for treating type 2 diabetes.

Which drug helps to lose the most weight?

Tirzepatide, the main ingredient in both Zepbound and Mounjaro, was found in trials to achieve an average weight loss of 26% in one year. In Eli Lilly’s SURMOUNT-4 trial of 783 adults who were overweight or obese but without diabetes, random participants who took the drug for 36 weeks were switched to a placebo and at 88 weeks maintained a 9.5% weight loss from their baseline.

Eli Lilly’s experimental drug retatrutide is still in trials, but its phase two test results have already seen participants lose 24% of their body weight at 48 weeks.

In Novo Nordisk’s semaglutide trials, half of the participants had lost 15% of their body weight at 68 weeks, with a third losing 20%.

Available after Thanksgiving, Zepbound in the US will cost $1,059.87 for a month’s supply, which is more than 20% cheaper than Wegovy at $1,349 per month.

With employers evaluating the cost of adding weight-loss drugs to their insurance coverage plans, price may matter—and the efficacy of the drugs in helping people lose weight might get increasingly scrutinized.