Lilly's weight-loss medications Mounjaro and Zepbound are gaining market share on Novo's Wegovy and Ozempic, but investors remain unconvinced.

No one stays on top forever. It’s a lesson that Ozempic maker Novo Nordisk may be painfully learning about. The Danish pharmaceutical company has enacted a hiring freeze—the latest sign of a sinking financial outlook for the once-titan of the obesity treatment world.