Lilly holds about 60% of US obesity market as Zepbound and Foundayo outpace Wegovy

Eli Lilly's Zepbound and its oral GLP-1 Foundayo held about 60% of the US branded obesity market through the summer of 2026, while Novo Nordisk's Wegovy franchise held roughly 40%, according to IQVIA prescription data cited by Citi and Jefferies ^[1].

The split was stable for weeks. One mid-August reading put it at 60.1% for Lilly and 39.9% for Novo ^[1]. Across the broader GLP-1 market, which includes diabetes use, Lilly's tirzepatide — the molecule in Zepbound and Mounjaro — held nearly 57% versus about 49.5% a year earlier, while Novo's semaglutide, the molecule in Wegovy, Ozempic and Rybelsus, was roughly flat at 37% ^[1].

Weekly prescriptions for both oral products kept climbing into September. In the most recent reporting period cited Sept. 11, Novo's Wegovy pill reached about 183,000 total prescriptions, up from 181,000 the week before, while Foundayo rose nearly 8% to 47,500 ^[1]. Citi noted that IQVIA may still be missing some Foundayo prescriptions dispensed through telehealth channels, so the recorded figure may understate the drug's volume ^[1].

The injectables remain far larger. Zepbound scripts rose 1.6% to a little fewer than 772,000 in early September, and total Wegovy scripts — injectable plus pill — increased 2.7% to 513,500 ^[1]. The pill accounted for 35% of all Wegovy scripts, a share that has hovered around a third for months and has struggled to break above that level ^[1].

Foundayo's launch has been slower. It crossed 40,000 weekly prescriptions in its 20th week, posting 40,862 in the Aug. 28 update, compared with the roughly 57,000 the Wegovy pill drew in week six of its own launch ^[1]. Lilly reported $98 million in Foundayo sales for the second quarter, including $67 million in the US, a result that disappointed many analysts ^[1]. CEO David Ricks said on an earnings call that Lilly began broad direct-to-consumer marketing after securing commercial access across the three major pharmacy benefit managers in June; CVS was the last of the three to add coverage, starting June 1 ^[1].

Classwide, Citi said total GLP-1 prescriptions rose 5.4% over the prior four weeks, compared with a 6.8% decline in the same stretch a year earlier — a 12-percentage-point swing the analysts attributed to oral GLP-1 therapies broadening access and drawing in new patients ^[1].

Why it matters for patients

Two oral GLP-1 products are now part of the market: the Wegovy pill, which is oral semaglutide, and Lilly's Foundayo, which is orforglipron ^[1]. The Wegovy pill has by far the larger prescription base, but Foundayo has been growing from a much smaller start and its share of new prescriptions, which exclude refills, reached 21.5% in the oral obesity market in late August ^[1].

Coverage has been a moving target. Foundayo gained commercial access across the three major pharmacy benefit managers only in June, while the Wegovy pill had full coverage in its first week on the market, according to Jefferies ^[1]. The Medicare GLP-1 Bridge program, which went live July 1, offers coverage for certain weight-loss medications, including Foundayo, at a $50 monthly copayment ^[1]. Jefferies observed that Wegovy has been relatively flat since that program began ^[1].

How much of the gap between the two oral drugs reflects real demand versus gaps in the data has not been established. Citi has said IQVIA's capture of telehealth prescriptions is incomplete, and it is not clear how much of Foundayo's growth came from better data collection rather than faster actual growth ^[1]. The size of that missing volume has not been disclosed.

What happens next

The prescription tracker is updated weekly using IQVIA data cited by Citi and Jefferies ^[1]. Novo Nordisk and Eli Lilly both reported second-quarter results on Aug. 5 ^[1]. A date for their next quarterly earnings reports has not been reported.