Deep dive: The oral obesity wars

Eli Lilly’s obesity pill Foundayo—generic name orforglipron—won FDA approval on April 1, adding another chapter to the epic battle for the weight loss market between Lilly and chief competitor Novo Nordisk, whose oral Wegovy launched in January. The race looks like it could be a photo finish, with Novo having a few months’ head start and appearing to hold an efficacy edge in Phase 3 trials while Lilly’s pill is easier to manufacture and can be taken with food.

Meanwhile, Lilly and Novo are unlikely to be alone in the oral obesity therapies market for long. With a forecasted $9.3 billion by 2035 on the line, companies including Pfizer, Structure Therapeutics and Viking Therapeutics are nipping at the heels of the two juggernauts.

While Lilly has emerged the clear leader in the injectables game—its Zepbound elicited 47% more weight loss than injectable Wegovy in a head-to-head trial—Novo might have the efficacy edge when it comes to pills. Oral Wegovy generated 16.6% weight loss at 72 weeks while Foundayo led to 11.2% at the same time point in their respective Phase 3 trials.

Foundayo bested Novo’s Rybelsus—an older formulation of semaglutide intended for type 2 diabetes—in a head-to-head trial published in February, reducing patients’ weight by 19.7 lbs vs. 11.0 lbs for oral semaglutide. Importantly, no head-to-head studies have been conducted between Foundayo and oral Wegovy.

Foundayo was approved with a clean label, BMO Capital Markets said in a note to investors on April 1. The Wegovy pill, meanwhile, must be taken with water, with no food and drink for at least 30 minutes. However, a closer look at Foundayo’s label reveals a few potential sticking points for patients, including that Lilly’s pill might make oral contraception less effective; this caution is not listed for oral Wegovy. Additionally, according to Foundayo’s approval letter, the FDA is requiring data from another clinical trial to assess a signal of a serious risk of retained gastric contents and to identify “an unexpected serious risk for major adverse cardiovascular events (MACE), drug-induced liver injury (DILI), and exposure to orforglipron during lactation.” Lilly may have at least partially answered the agency’s concerns with the results of a Phase 3 diabetes trial in which no liver signals were observed.

An increased risk of thyroid tumors, including thyroid cancer, is a possibility with both GLP-1 options, and both come with a host of well-known possible gastrointestinal side effects.

Foundayo may have the manufacturing edge, as small molecules are easier to manufacture than peptides like the Wegovy pill—something that could help it in both supply chain and revenue potential. And Lilly has taken it a step further, pivoting from the capsule that was used in Foundayo’s Phase 3 trials to a tablet for the marketed version, according to Leerink Partners. A tablet uses fewer active pharmaceutical ingredients and is more efficient to manufacture, the analysts wrote in an April 1 note to investors.

Foundayo and oral Wegovy are priced competitively, with each pill on the market for between $149 to $299 per month, depending on dose, and as low as $25 through insurance.

While it’s early going for both—especially Foundayo—oral Wegovy’s strong launch could be an indicator for the market. The Wegovy pill reached more than 3,000 patients in its first week of sales, while Foundayo hit 1,390 prescriptions during its first week on the market. However, analysts at RBC Capital Markets said in an April 17 note that they believe Foundayo’s initial capture is from two days, while oral Wegovy’s is based on five days.

Novo continues to see momentum with oral Wegovy. The pill hit 113,354 prescriptions in its 12th week, BMO Capital Markets said in an April 17 note, up 7.6% from the previous week.

Editor’s note: A version of this article was originally published as a special edition of ClinicaSpace on April 20, 2026.