Novo Nordisk's total Wegovy scripts slip and its US obesity share falls to 39.9%

Novo Nordisk's Wegovy franchise lost ground in the US obesity market during the week covered by an Aug. 14, 2026 update from Fierce Pharma's Oral GLP-1 Tracker, which draws on IQVIA prescription data cited by Citi analysts. Total Wegovy prescriptions, including both the pill and the original injectable, fell 1.1% sequentially to about 495,500 ^[1]. As a result, Novo gave up roughly 0.7 percentage points of obesity market share to Eli Lilly's Zepbound, putting the split at 39.9% for Novo and 60.1% for Lilly ^[1].

The decline came even though Novo's Wegovy pill has held the lead in the oral GLP-1 race for months. In the same period, the pill's share of all Wegovy scripts actually fell back to 33%, down from 35% the previous week, as pill scripts dropped to about 163,000 from a prior high of roughly 172,000 ^[1]. Fierce Pharma noted that Novo's oral option "seems to be hitting a market share ceiling," since its share within the Wegovy franchise has struggled to break past one-third for months ^[1].

Meanwhile, Lilly's oral drug, Foundayo, kept climbing. It logged 38,928 total scripts, another step up from its previous record of 34,219 the week before ^[1]. That growth trend continued in later weeks tracked by Fierce Pharma, with Foundayo eventually topping 40,000 weekly scripts by late August and reaching nearly 47,500 by the update dated Sept. 11 ^[1]. Even so, Citi analysts flagged that IQVIA data may still be missing some Foundayo prescriptions written through telehealth channels, meaning the pill's true uptake could be somewhat higher than reported ^[1].

Zooming out, the broader GLP-1 obesity market has remained tilted toward Lilly for most of 2026. In the week ended Aug. 21, Lilly held a 56.7% share of the combined diabetes and obesity market compared with Novo's 37.1%, according to Citi's tally ^[1]. By the update dated Sept. 11, Lilly's tirzepatide share of the total GLP-1 market had grown to nearly 57%, up from about 49.5% a year earlier, while Novo's semaglutide share stayed roughly flat around 37% ^[1].

Why it matters for patients

These weekly prescription swings are one signal of how competitive, and how volatile, the obesity drug market has become. For patients already taking Wegovy or considering it, a shrinking market share for Novo does not change how the medicine works or its safety profile, but it can affect the broader landscape around it, including insurer negotiating leverage, pharmacy stocking decisions, and how aggressively each company markets or discounts its products. A rising rival like Zepbound, and now Foundayo as an oral option, gives patients more choices, which over time could influence pricing and access, though the sources do not report specific price changes tied to this particular week's data ^[1].

The fact that Novo's Wegovy pill has plateaued at around one-third of total Wegovy prescriptions, rather than steadily displacing the injectable, suggests that many patients and prescribers are not yet switching from injectable to oral semaglutide at a fast pace ^[1]. Fierce Pharma also pointed out that Wegovy's overall numbers have been