GLP-1 Weekly Tracker: Wegovy oral pill growth slows, Foundayo data not yet included

Overview

This report is Bernstein's weekly prescription tracker for the U.S. GLP-1 market, focusing on the growth pace after Wegovy oral pill launch, the early data gap for Lilly's Foundayo launch, and market share shifts among Zepbound, Mounjaro, Ozempic, and Wegovy across different formulations. The report is based on IQVIA prescription indicators and notes that IQVIA coverage of newly launched channels may lag.

Core views

The report argues that overall U.S. GLP-1 demand remains strong, but total prescriptions were nearly flat this week and growth momentum has slowed modestly versus earlier periods. Lilly continues to lead Novo in TRx share, with Zepbound and Mounjaro remaining the main sources of Lilly's share advantage; Novo's Wegovy oral pill still shows an early trajectory stronger than the supply-constrained launch path of Zepbound, but its week-over-week growth has clearly slowed. Because Foundayo has launched but has not yet appeared in this week's IQVIA weekly data, the near-term competitive landscape still needs to be validated by subsequent data.

Analysis framework

The report uses IQVIA weekly prescription data to track TRx, NRx, NBRx, RRx, and CBRx, comparing Lilly and Novo in terms of prescription volumes, market share, year-over-year growth, and new-patient acquisition within the GLP-1 category. It also compares the early launch trajectories of oral Wegovy and Zepbound, and combines this with Novo's internal data disclosed at its AGM to judge that IQVIA capture may be understated.

Methodology notes

• Prescription data frameworkIQVIA TRx/NRx/NBRx tracking

  TRx

  TRx refers to total prescription volume, including new prescriptions and refills, and is the top-level indicator of product scale and market share.

• Prescription data frameworkIQVIA new prescription split

  NBRx

  NBRx refers to new-to-brand prescriptions, counting only patients who have not used the brand in the past 12 months, so it is closer to a true new-patient acquisition metric.

• Prescription volume decompositionIQVIA TRx/NRx/NBRx tracking

  TRx = NRx + RRx；TRx = NBRx + CBRx

  The report explains that total prescriptions can be decomposed into new prescriptions plus refills, or into new-to-brand prescriptions plus continuing-brand prescriptions, to distinguish sources of growth.

• Data quality noteIQVIA coverage lag and channel capture rate

  new launch channel capture rate

  Channels such as Foundayo and NovoCare may not yet be fully captured by IQVIA; Novo says IQVIA may currently be capturing only about 50% of the actual demand for Wegovy oral pills.

• Valuation methodDCF and multiples-based equal-weight blend

  LLY target price valuation

  The report states that LLY's target price uses an equal-weight blend of DCF and multiples-based valuation, with DCF assumptions including a 7.6% WACC, a 5% FCFF CAGR through 2043, and a 2.5% terminal growth rate, while the multiples method uses a 32x P/E on FY27E adjusted EPS.

Asset mapping & comparison

Structured mapping from thesis to named assets (strengths, weaknesses, peers, risks).

• Eli Lilly & Co / LLY

  Core covered company and rating subject

  Strengths

  Lilly's GLP-1 TRx share reached 60.5%, with both Zepbound and Mounjaro maintaining high share; the report maintains an Outperform rating and a $1,300 target price.

  Weaknesses

  Zepbound's weekly share fell by 0.9 percentage points this week, and its NBRx share had previously been pressured by Novo's oral pill launch.

  Comparison

  Relative to Novo, Lilly leads in total TRx share; however, Novo's oral Wegovy shows stronger demand in its early launch trajectory.

  Risks

  If Foundayo's launch-phase data are not yet in IQVIA and actual ramp is slower than expected, near-term market expectations could come under pressure; manufacturing scale-up and obesity TAM pressure are also downside risks.

• Novo Nordisk / Novo

  Main competitor

  Strengths

  Wegovy oral pills reached about 105k cumulative prescriptions in week 13, and early performance is ahead of Zepbound's supply-constrained launch trajectory; Novo says IQVIA may be underestimating actual demand.

  Weaknesses

  Novo's overall TRx share was 39.5%, below Lilly's; Ozempic year-over-year growth continues to decline, and Wegovy oral pill's week-over-week growth has slowed to 4%.

  Comparison

  Novo has an early-mover advantage in oral GLP-1, but Lilly remains stronger on overall GLP-1 share and the Zepbound/Mounjaro mix.

  Risks

  If subsequent IQVIA data confirm that oral Wegovy growth continues to slow, the market may lower expectations for the product's ramp curve.

• Zepbound

  Lilly obesity GLP-1/GIP product

  Strengths

  4-week rolling year-over-year growth is about 100%, absolute NBRx numbers have remained around 60k this year, and growth in the LillyDirect cash-pay channel remains strong.

  Weaknesses

  Weekly TRx share fell to 27.2%, and NBRx share had previously been affected by Novo's oral pill launch.

  Comparison

  Compared with Wegovy oral pill, Zepbound's early launch was constrained by supply; the report says Wegovy oral pill's apparent trajectory is above that constrained benchmark.

  Risks

  Rising oral competition, channel data capture differences, and shifts in new-patient share may affect short-term trend interpretation.

• Mounjaro

  Lilly diabetes GLP-1/GIP product

  Strengths

  Weekly TRx share rose to 33.3%, still an important support for Lilly's total share.

  Weaknesses

  The 4-week year-over-year growth rate is 45.5%, below the roughly 60% level seen from August 2025 to January 2026.

  Comparison

  Mounjaro's share is higher than Zepbound's and is one of the largest single-product contributors to Lilly's overall GLP-1 TRx.

  Risks

  Continued slowing growth could weaken Lilly's total prescription growth elasticity.

• Wegovy pill

  Novo oral obesity GLP-1 product

  Strengths

  Cumulative prescriptions reached about 105k in week 13 after launch, with early performance ahead of Zepbound's supply-constrained launch trajectory; Novo's internal data suggest IQVIA may understate actual demand.

  Weaknesses

  This week's week-over-week growth is only 4%, the lowest since launch.

  Comparison

  Compared with Zepbound, its oral administration may offer a convenience advantage, but Lilly still leads overall market share.

  Risks

  If growth continues to slow or actual patient retention comes in below expectations, the oral product's competitive advantage could be weakened.

Key data

• Total weekly GLP-1 prescriptions2.46MFor the week ended April 3, 2026, essentially flat versus the prior week, with an absolute increase of about 3k.
• sema+tirz 4-week year-over-year growth40.5%Below last week's 41.4%.
• Lilly TRx market share60.5%Including 27.2% for Zepbound and 33.3% for Mounjaro.
• Novo TRx market share39.5%Including 12.0% for Wegovy pen, 4.5% for Wegovy pill, and 23.0% for Ozempic.
• Cumulative Wegovy oral prescriptionsabout 105kIn week 13 after launch, up from about 101k last week, with week-over-week growth slowing to 4%.
• Zepbound weekly market share27.2%Down 0.9 percentage points from last week; 4-week rolling year-over-year growth is about 100%.
• Zepbound NBRx shareabout 44%Recovered from a low of 41% after being pressured by the launch of Novo's oral pill.
• Mounjaro weekly market share33.3%Up 1.1 percentage points from last week; 4-week year-over-year growth was 45.5%.
• Wegovy pen 4-week average year-over-year growth36.9%Below the prior week's 39.2%.
• Ozempic 4-week average year-over-year growth-10.7%Year-over-year decline continued, versus -10.2% in the prior week.
• Overall semaglutide year-over-year growth14.0%Combining Ozempic and Wegovy, below last week's 14.2%.
• LLY rating and target priceOutperform；$1,300The report explicitly states Bernstein rates LLY Outperform with a $1,300 target price.

Impact & implications

From an investment perspective, this week's data continue to support Lilly's leading share position in the GLP-1 market, but oral GLP-1 competition is entering a new phase: Novo's Wegovy oral pill has shown strong early prescription performance but is slowing, and Lilly's Foundayo launch is not yet reflected in IQVIA weekly data. The next few weeks of data will determine whether oral products materially change the new-patient share mix. If Foundayo can scale quickly, it could reinforce Lilly's product portfolio advantage in obesity; if Wegovy oral pill actual demand is underestimated because of IQVIA under-capture, Novo's short-term competitive pressure may be less severe than the headline data suggest.

Risks

• IQVIA coverage of Foundayo, NovoCare, and other new channels lags, so short-term data may understate true demand.
• Wegovy oral pill week-over-week growth has slowed to the lowest level since launch, which may suggest the initial demand release is moving into a plateau.
• Zepbound share and NBRx share were affected by Novo's oral pill launch; oral GLP-1 competition could alter the new-patient acquisition landscape.
• The obesity TAM may face pressure from demand, regulation, pricing, competition, and compounded drugs.
• If manufacturing scale-up stalls, Lilly's obesity business expansion could be constrained.
• High-risk M&A or R&D execution could destroy value.

What to watch

• Foundayo's first showing in IQVIA weekly data released on April 17.
• Early capture rate and channel coverage for Foundayo daily TRx after more than a 36-hour lag.
• Whether Wegovy oral pill's subsequent week-over-week growth continues to slow, or whether it is revised up as IQVIA adds capture.
• Whether Zepbound NBRx share can continue to recover from about 44%, and whether absolute NBRx can remain around 60k.
• Continued growth in Zepbound vial and KwikPen within the LillyDirect cash-pay channel, as well as the growth trend for the auto-injector format.
• Whether Mounjaro's 4-week year-over-year growth continues to fall from the roughly 60% level previously seen.