Shares of Eli Lilly and Company (NYSE:LLY) slipped around 2% after the latest weekly prescription data pointed to mixed trends across its GLP-1 drug portfolio.
Weekly Prescription Trends Mixed
According to IQVIA data cited by Morgan Stanley, Mounjaro prescriptions for the week ending April 17, 2026 reached roughly 758,400 total prescriptions and 367,900 new prescriptions, up from 749,500 and 361,700 the previous week.
Zepbound recorded 615,300 total prescriptions and 350,600 new prescriptions, compared with 632,500 and 346,400 in the prior week, indicating a slight decline in overall volumes but continued growth in new starts.
Broader Portfolio Shows Slight Decline
Across its broader GLP-1 lineup—including Mounjaro, Trulicity, Zepbound and Foundayo—total prescriptions came in at 1,503,100 for the week, down 0.3% from 1,508,000 previously.
The combined total for Mounjaro, Zepbound and Foundayo reached 1,377,400 prescriptions, also representing a 0.3% week-on-week decline.
Despite this, Eli Lilly maintained an approximate 59% share of new prescriptions within the GLP-1 category, unchanged from the prior week. The overall GLP-1 market continued to expand, growing about 32% year-on-year.
Early Launch Data for Foundayo
Foundayo, which was approved on April 1, 2026 and launched on April 9, recorded around 3,700 total and new prescriptions in its second week on the market.
This compares with approximately 18,400 prescriptions for oral Wegovy during its second week following its January 2026 launch.
Outlook and Analyst Commentary
“We see ~6% upside to ’26 M+Z ests,” Morgan Stanley analysts commented, referring to projections for Mounjaro and Zepbound in 2026.
The firm highlighted that it continues to track the rollout of Mounjaro for type 2 diabetes and Zepbound for obesity as key growth drivers, particularly in terms of their influence on overall GLP-1 demand and competitive positioning.