The battle for U.S. market share could amount to a must-win for Novo: The weight loss segment accounted for more than half of its sales in 2025. Lilly is estimated to have around 60% of the branded GLP-1 market globally, while Novo has about 39%. Novo has also highlighted a gap in the "preference share" for Wegovy versus Lilly's injections. Lilly's Zepbound has shown more pronounced weight loss than Wegovy and has become the preferred medicine among patients and prescribers, despite launching years after Novo's drugs. In the U.S., Novo estimates that between 7 and 8 patients out of 10 go to Lilly. Meanwhile, in the compounding market, the share of copycats for Novo's drug far outweighs that of Lilly's. "It's a curious question as to why in the branded market, Lilly has a much bigger share than Novo but in the compounded market, there's a lot more of Novo's molecule than there's of Lilly's," Baker noted. "We don't know the answer." Novo is banking on the Wegovy pill to help with its eroding market share and says it's already reaching entirely new patients. Doustdar has said that 88% of people on the pill are taking the lowest starter dose of the drug, signaling that many patients have been waiting on oral options. Lilly is expected to launch its rival weight loss pill, orforglipron, in the second quarter of 2026. Investors are closely watching how that will pan out, especially as Novo has lost its first-mover advantage before. "They're putting a lot of muscle behind the marketing of (Wegovy pill), including now a reinvigorated direct-to-consumer channel, which they were a little bit late to arrive at," TD Cowen analyst Michael Nedelcovych told CNBC. "That seems to be paying dividends."

Doustdar touted the pill's efficacy, which is on par with the Wegovy injection and superior to Lilly's oral drug, based on separate clinical trials. The Wegovy pill showed around 16.6% weight loss on average compared with roughly 12.4% on average with Lilly's oral drug. "If you use these two numbers, basically you have a 40% difference between the efficacy of these pills," he said. "I think this is going to be a very main, main selling point of the pill." When Lilly eventually launches orforglipron, its primary marketing point will likely be aimed at convincing customers that the Wegovy pill is inconvenient because of certain food restrictions. That makes Novo's head start extra important as it offers them a chance to lay the groundwork and convince people of the contrary. Novo contends that those dietary requirements won't hinder uptake. But Leerink Partners analyst David Risinger told CNBC last week that it could help Lilly's pill eventually generate greater sales globally. Still, while sales of both companies' drugs may soar, prices are coming down across the board.

The GLP-1 market is facing broad price erosion following landmark "most favored nation" deals between companies and the Trump administration. It's unclear how much of the price decline can be offset by volume increases. "No matter how well we do initially to catch up with the price decrease ... of course, mathematically, (it) takes a bit of time," Doustdar said, adding the company is "very hopeful" and "working day and night to accelerate those volume uptakes." Analysts largely believe Novo is being intentionally cautious with its sales projections, baking in the expected pricing pressures. "There are a number of pushes and pulls in 2026, some have quite high visibility, some have lower visibility .… I think Novo have added in the things of high visibility more than the things of low visibility," Baker said. Where there's higher visibility is where pricing is coming down, generics in Canada and a few other markets, and restrictions on Medicaid for some of their drugs, Baker said: "They've got these negatives in quite fully. "Given the problems they had last year, they don't want to overpromise and underdeliver," he said. Novo's guidance likely doesn't include any reduction in the volume of compounded drugs on the market, as the FDA's announcement of its "decisive steps" to restrict GLP-1 compounding came after the guidance was released. But the price sensitivity of consumers for weight loss drugs remains a big unknown, which makes greater volumes and more access points important. Novo is anticipating Medicare coverage for weight loss treatments, expected to begin later this year, to open up a 15 million-patient opportunity, Doustdar told CNBC. Around 67 million Americans are covered by Medicare, but "when you take a look at specifically our products and the target group, I think around 15 million people would be a good number to target," Doustdar said. Though he said Medicare access to obesity treatments will open up gradually.

Novo is also pinning its hopes on other drugs in its pipeline to help it claw back market share. That includes a higher dose — 7.2 milligrams — of Wegovy, which is waiting for FDA approval and could make the drug a stronger competitor to Zepbound. Doustdar said that higher dose helps patients lose around 21% of their weight, which is "very much on par" with the highest dose of Zepbound. Wegovy, under its approved doses, has shown around 15% weight loss on average in clinical trials. "When that comes to the market, my thought, my wish, my hope is that people will realize, OK, now we have two products with similar efficacy," Doustdar said. He added that "hopefully will also change the dynamic as we go forward," referring to the market's increasing preference for Zepbound. BMO's Seigerman said it's difficult to say whether that will be the case, as Zepbound is already entrenched as the best product in the injectable market. Novo expects its next-generation treatment called CagriSema to enter the market later this year. That experimental weekly injection combines semaglutide with cagrilintide, which mimics another gut hormone called amylin. Novo Nordisk has defended CagriSema's trial results, which disappointed investors, coming in under the expected 25% weight loss on average. On Wednesday, Doustdar said the company was "penalized quite harshly by the stock market" for those results, which showed around 23% weight loss. But he said the drug would be "one of the best products out there" if it were available today. To assess the real efficacy of the drug, "you need to look at all the data together," he added, pointing to three upcoming Phase 3 trials for the drug, including one study that pits CagriSema against Zepbound. When asked whether Novo needs to further diversify away from obesity like competitors, Doustdar said that the company doesn't see obesity or diabetes as a single, monolithic disease and sees more opportunity in developing multiple, specialized therapies within the category. While the world labels millions of patients simply as "obese," he said the underlying biology and severity of the condition vary widely — from someone who needs to lose a modest amount of weight to someone with severe complications like fatty liver disease requiring a transplant. And as the market matures, Novo's sales are still growing year on year on a constant currency basis, albeit at a slower pace than before. Only time will tell when, or if, that will change. Correction: This story has been revised to reflect that Novo Nordisk shares have traded in the range of $43.24 to $64.16 this calendar year. A previous version misstated the time range of the trading spread.