H1 2026 GLP-1 franchise reporting places Eli Lilly (NYSE: LLY) tirzepatide (Mounjaro plus Zepbound) at nearly $27.7 billion in first-half revenue, an 88% year-over-year increase, versus Novo Nordisk (NYSE: NVO) semaglutide (Ozempic plus Wegovy plus Rybelsus plus Wegovy pill) at approximately $17.5 billion. The revenue gap between the two GLP-1 leaders has widened from under $2 billion at the same point last year to $10.2 billion, driven by Zepbound share gains in U.S. obesity following SURMOUNT-5 superiority data over Wegovy, Mounjaro upside in international markets (China +93% CER, Rest of World +136%), Foundayo (orforglipron) first commercial quarter contribution of $98 million, and semaglutide patent expiries approaching in select markets (generic Ozempic expected in Canada). Novo has cut 12,000 positions in H1 2026 and lowered gross margin outlook to 78%, while Lilly raised full-year 2026 revenue guidance to $85-87 billion.
Novo Nordisk (NYSE: NVO) filed a federal lawsuit Tuesday July 21, 2026 against Eli Lilly (NYSE: LLY) alleging that Lilly has run 'deceptive' advertising campaigns for its GLP-1 drugs Zepbound and Mounjaro (both tirzepatide), per STAT News reporting. The Novo complaint reportedly targets marketing claims that make Lilly's tirzepatide franchise appear more effective than the underlying clinical data support relative to Novo's Wegovy and Ozempic (both semaglutide). The lawsuit arrives against a competitive backdrop where Lilly has been extending its US commercial lead in the obesity market: Q1 2026 sales showed Mounjaro at $8.7 billion (up 125% year-over-year) and Zepbound at $4.2 billion (up 80%), while Novo Nordisk faced flat-to-declining semaglutide revenue after March 2026 price cuts, and Lilly overtook Novo in US GLP-1 market share. The SURMOUNT-5 head-to-head Phase 3 trial published earlier in 2026 showed superior efficacy for tirzepatide over semaglutide on weight loss endpoints; Novo's complaint appears to focus on how Lilly extrapolates the SURMOUNT-5 comparative data into consumer-facing advertising. The dispute frames the GLP-1 marketing battlefield ahead of Q2 earnings reports (Lilly August 5, Novo August 6).