It’s easy to make a medical case for blockbuster weight loss drugs like Wegovy and Zepbound, which have been shown to prevent heart attacks and strokes and save lives.

But for the employers and government programs being asked to pay for the medications, the financial case for them is less clear. Are the drugs’ benefits worth their enormous cost?

The answer right now is no, according to a new study published on Friday in the journal JAMA Health Forum, by researchers at the University of Chicago.

To be considered cost effective by a common measure used by health economists, the price of Novo Nordisk’s Wegovy would need to be cut by over 80 percent, to $127 per month, the researchers concluded. And Eli Lilly’s Zepbound would be cost effective only if its price fell by nearly a third, to $361 per month. (Zepbound warranted a higher price, the researchers said, because it produced greater benefits in clinical trials.)

“There’s no doubt that the drugs are demonstrating tremendous health benefits,” said David Kim, a health economist at the University of Chicago and the senior author of the study, which was funded by government grants. “The problem is the price is too high.”

There’s widespread hope that the drugs will effectively pay for themselves in the long run, by making patients healthier and preventing expensive medical bills. It’s not clear yet whether that will turn out to be true.