Lilly's 60% Market Share Confirms Novo's Slide

What happened

Eli Lilly now controls 60% of the U.S. weight loss drug market, surpassing Novo Nordisk as the leading GLP-1 player. This aligns with Novo's own admission in its 20-F that it lost U.S. weekly prescription leadership and volume share in both obesity and diabetes during 2025. The shift from scarcity-driven demand to access-and-price competition has accelerated, with Lilly's tirzepatide franchise capturing the majority of new starts. Novo's consumerized strategies—subscriptions and telehealth—have yet to reverse the trend, and policy-driven price compression (IRA, MFN) adds structural pressure. The stock's 10.4x P/E embeds expectations of continued erosion, but the narrative has shifted from 'defending a lead' to 'fighting for relevance' in a duopoly.

Implication

The 60% figure crystallizes the competitive damage: Novo is no longer the obesity leader. Its low valuation (10.4x P/E) reflects this, but the risk of a structural margin reset remains high. Investors need to see proof that volume can offset net price compression before considering a position. The bear case of $30/share looks more plausible if share loss continues and price wars deepen. Watch IQVIA TRx trends and any further discounting beyond published subscription tiers.

Thesis delta

The thesis shifts from 'incumbent under pressure' to 'confirmed market-share loser with no near-term catalyst to reverse the trend.' The 60% figure validates that Lilly's tirzepatide has decisively overtaken semaglutide in the U.S., and Novo's consumerized access strategies are not yet yielding share stabilization. The stock's cheap multiple may now be a value trap if gross-to-net deteriorates faster than volume grows.