Summary of Key Points
In the first half of 2026, Eli Lilly’s tirzepatide (used for diabetes management and weight loss under the brands Mounjaro and Zepbound) outperformed Novo Nordisk’s combination of semaglutides, with the gap between the two expanding from less than $2 billion in 2025 to $10.2 billion. Tirzepatide accounted for nearly 70% of Eli Lilly’s revenue, driving a significant increase in the company’s earnings and leading to an upward revision of its full-year forecasts. While semaglutides still represent over 70% of Novo Nordisk’s revenue, their growth rate has slowed, resulting in the company’s full-year forecast shifting from negative growth to zero growth. Novo Nordisk is attempting to turn things around with a newly launched oral weight loss drug and has also filed a lawsuit against Eli Lilly, intensifying the competition between these two GLP-1 giants.
I. Tirzepatide Outperforms Semaglutides by Over $10 Billion in Half a Year
In the first half of 2026, Eli Lilly’s tirzepatide sales totaled $27.693 billion, an increase of nearly 88% year-over-year. In contrast, Novo Nordisk’s semaglutide portfolio (including both injectable and oral versions for diabetes and weight management) only generated approximately $17.525 billion in sales. The gap between the two amounted to $10.2 billion—indicating that Eli Lilly has surpassed Novo Nordisk by a factor of more than five in just half a year. This suggests that the demand for tirzepatide is growing much faster than that for semaglutides, possibly due to patients’ greater recognition of its effectiveness or because Eli Lilly’s marketing strategy is more effective.
II. Tirzepatide Becomes Eli Lilly’s Cash Generator, Driving Massive Revenue Growth
Tirzepatide contributed nearly 70% of Eli Lilly’s revenue in the first half of the year, pushing the company’s total sales to $42.773 billion, a year-on-year increase of 51%. Due to strong performance in the second quarter, Eli Lilly raised its full-year revenue forecast to between $85 billion and $87 billion—meaning that tirzepatide alone could generate over $60 billion in earnings for the company this year. It’s clear that this single drug is a major contributor to Eli Lilly’s success.
III. Semaglutides Face Weak Growth, with Novo Nordisk Focusing on Oral Weight Loss Drugs
Although semaglutides account for 75.5% of Novo Nordisk’s revenue, their growth rate has slowed significantly in the first half of the year: the injectable weight loss version, Wegovy, only saw a 7% increase, while the injectable diabetes treatment, Ozempic, declined by 2%, and the oral diabetes version fell by 9%. To reverse this trend, Novo Nordisk launched an oral version of Wegovy, which sold for $855 million in the first half of the year, with prescriptions exceeding 5 million in the United States. However, even with these efforts, Novo Nordisk’s adjusted full-year sales forecast remains between -6% and 0%, indicating significant pressure on semaglutide sales.
IV. Intense Competition: Novo Nordisk Sues Eli Lilly over Marketing Claims
The competition between the two companies has escalated to court battles. In July, Novo Nordisk sued Eli Lilly, accusing it of misleading consumers through outdated research that compared the higher dose of Eli Lilly’s tirzepatide with the lower dose of Novo Nordisk’s semaglutides, making tirzepatide appear more effective. Novo Nordisk argued that “Americans have a right to know the true treatment options,” implying a fear of losing market share to Eli Lilly. This highlights the fierce competition in the GLP-1 market, where both companies are now competing not only on product quality but also on legal grounds.
V. GLP-1 Market: Eli Lilly Leads for Now, but Novo Nordisk Hasn’t Given Up
Eli Lilly currently has a clear advantage in sales, but Novo Nordisk is not backing down. It continues to develop oral weight loss drugs and uses litigation to challenge its competitor. The competition between the two companies is expected to intensify in the future, with both focusing on improving product effectiveness, enhancing marketing strategies, and addressing the threat of generic versions (especially for semaglutides). For consumers, this means more options for diabetes and weight management medications, potentially at more affordable prices.