Oral Wegovy growth has slowed, and post-launch competitive data for Foundayo still needs validation

Overview

This is Bernstein’s US GLP-1 prescription-data tracking report, focused on the prescription trajectory of Novo Nordisk oral Wegovy before and after Lilly’s oral drug Foundayo launch. The report uses weekly IQVIA prescription metrics to monitor TRx, NBRx, NRx, and RRx, and compares the market share and growth of Novo’s Wegovy/Ozempic versus Lilly’s Zepbound/Mounjaro in the US market.

Core views

Oral Wegovy remains at a substantial level during its early commercial period, with week-13 TRx around 105k and a launch trajectory above Zepbound’s constrained supply phase; however, growth has clearly slowed, with week-over-week growth at only about 4%. Overall GLP-1 weekly prescriptions were roughly flat, and Lilly continues to hold a higher company share. Novo management believes IQVIA may be capturing only about 50% of true oral Wegovy demand, so the report suggests observed prescription data may understate true demand. Foundayo has launched, but its impact is not yet reflected in this week’s data, and competitive effects need to be validated in subsequent IQVIA updates.

Analysis framework

The report mainly uses IQVIA prescription data, tracking weekly TRx total prescriptions, NBRx new-brand prescriptions, NRx new prescriptions, and RRx refills, and combines four-week rolling year-over-year growth, company market share, brand share, and post-launch week counts to assess the ramp speed of the oral GLP-1 new launch, patient acquisition trends, and the competitive dynamics between Novo and Lilly.

Methodology notes

• Prescription Data TrackingIQVIA TRx

  Total TRx

  TRx counts all prescriptions dispensed, including both new prescriptions and refills, and serves as a top-line indicator of overall drug sales volume and share.

• Prescription Data TrackingNBRx

  New-Brand Prescriptions

  NBRx counts prescriptions for patients who have not used the brand in the prior 12 months, making it closer to true incremental patient acquisition and it can be composed of NTS Rx and Switch/Add Rx.

• Prescription Data TrackingNRx vs. NBRx

  Distinguishing NRx from NBRx

  NRx may include existing patients renewing treatment but receiving a new prescription number; NBRx is stricter and only counts patients who have not used the brand in the prior 12 months, so it is more suitable for measuring brand acquisition.

• Valuation MethodDCF and Relative Valuation

  LLY Valuation Disclosure

  The report discloses a 50/50 blend of DCF and multiples for LLY, with DCF assumptions including 7.6% WACC, 5% FCFF CAGR through FY43E, 2.5% terminal growth, and a 32x P/E on FY27E adjusted EPS. This valuation disclosure applies to LLY, not NVO.

Asset mapping & comparison

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

• NOVO NORDISK A S / US.NVO

  Primary coverage and data tracking subject of the report

  Strengths

  Oral Wegovy week-13 TRx was about 105k, and the launch trajectory was above Zepbound’s constrained-supply phase; Novo says IQVIA may understate true demand.

  Weaknesses

  Oral Wegovy week-over-week growth fell to 4%; Novo company TRx share was 39.5%, lower than Lilly; Ozempic four-week year-over-year growth was -10.7%.

  Comparison

  Relative to Lilly, Novo trails in company TRx share, but oral Wegovy’s early launch trajectory can still be compared with Zepbound’s constrained-supply period.

  Risks

  Competition may intensify after Foundayo’s launch, IQVIA capture rates are uncertain, Wegovy growth is slowing, and Ozempic is down year-on-year.

• Eli Lilly / LLY

  Primary competitor and the report’s disclosed rating subject

  Strengths

  TRx company share was 60.5%; Mounjaro share was 33.3%, and Zepbound’s NBRx absolute volume has remained around 60k this year; the report disclosed LLY as Outperform with a $1,300 target.

  Weaknesses

  Zepbound weekly share fell to 27.2%, down 0.9 percentage points from last week; four-week year-over-year growth declined from 105% to 100%.

  Comparison

  Lilly leads overall company share vs Novo; Foundayo’s launch may further change the competitive landscape for oral GLP-1.

  Risks

  Obesity TAM, regulation, pricing, competition, manufacturing expansion, and high-risk M&A or R&D spending could create downside risks.

Key data

• Total weekly GLP-1 TRx2.46MFor the week ended April 3, 2026, up 0.1% from last week, about 3,000 more prescriptions.
• sema+tirz four-week year-on-year growth40.5%Slightly down from 41.4% last week.
• Lilly TRx share60.5%Including Zepbound 27.2% and Mounjaro 33.3%.
• Novo TRx share39.5%Including injectable Wegovy 12.0%, oral Wegovy 4.5%, and Ozempic 23.0%.
• Oral Wegovy week 13 TRxabout 105kUp about 4,000 from about 101k last week, with weekly growth of about 4%.
• Zepbound share27.2%Down 0.9 percentage points from last week; four-week rolling year-over-year growth is about 100%.
• Mounjaro share33.3%Up 1.1 percentage points from last week; four-week year-over-year growth 45.5%.
• Ozempic four-week year-over-year growth-10.7%Further weakened from -10.2% last week.
• Injectable Wegovy four-week year-over-year growth+36.9%Below the prior week’s +39.2%.
• Foundayo data visibility timingExpected April 17 weekly TRx releaseThis week’s update has not yet included Foundayo IQVIA data.

Impact & implications

For Novo, oral Wegovy’s early launch performance remains a support, but slowing growth and Lilly’s higher TRx share are increasing competitive pressure. After Foundayo’s launch, investors need to watch whether it erodes Novo’s incremental patient gains for oral Wegovy, and whether IQVIA’s capture rate of NovoCare and other channels causes observable TRx to understate true oral Wegovy demand. For the GLP-1 segment, overall prescription volume still shows strong year-over-year growth, but short-term weekly momentum has plateaued, making share shifts among brands more important than total volume growth.

Risks

• The true post-launch prescription ramp of Foundayo is not yet reflected in this week’s IQVIA data, so short-term competitive impact remains uncertain.
• IQVIA may not fully capture channels such as NovoCare, leading to a gap between observed TRx and true oral Wegovy demand.
• Oral Wegovy’s week-over-week growth reached a low point after launch; if it continues to slow, Novo’s oral GLP-1 narrative could weaken.
• Ozempic continues to decline year over year, potentially hurting Novo’s overall semaglutide growth quality.
• The GLP-1 market faces downward pressure on obesity TAM from demand, regulation, pricing, competition, and combination therapies.
• If manufacturing capacity expansion falls short of expectations, it could constrain GLP-1 volume scaling.

What to watch

• Initial oral GLP-1 prescription performance of Foundayo in the IQVIA weekly TRx released for the week ending April 17.
• Capture rate and availability of Daily TRx after more than 36 hours of lag.
• Whether oral Wegovy’s subsequent week-over-week growth continues to slow or re-accelerates.
• Whether subsequent data validate the claim that IQVIA captures only about 50% of oral Wegovy demand.
• Whether Zepbound NBRx share continues to recover from around 44% and whether absolute NBRx remains near 60k.
• Whether the growth of Zepbound vial and kwikpen in LillyDirect cash-pay channels can continue.
• Whether Mounjaro share gains and Ozempic year-over-year declines continue to widen the company share gap between Novo and Lilly.