Hims & Hers Health Inc.’s stock was headed for a record session of losses Monday after pharmaceutical giant Novo Nordisk, maker of the weight-loss drug Wegovy, said it was ending a collaboration with the telehealth-consultation company less than two months after it started.

Key Takeaways Hims & Hers shares plunged 30% in intraday trading Monday after Novo Nordisk said it is pulling Wegovy from the platform, citing "illegal" and "deceptive" practices.The Danish drugmaker said Hims & Hers has continued to sell illicit compounded versions of its drug that it says may not be as safe.

Novo Nordisk cut off Hims & Hers Health from selling lower-priced Wegovy on Monday morning, but its explanation for the abrupt decision—which set Hims shares down more than 30%—doesn’t add up. Novo said that by selling personalized doses of compounded semaglutide,