Novo Nordisk, the maker of Wegovy and Ozempic, has launched legal action accusing its arch rival Eli Lilly of false advertising.

The maker of Wegovy and Ozempic, Novo Nordisk, has launched legal action accusing its arch rival Eli Lilly of false advertising in suggesting its weight-loss drugs perform better. The Danish company filed a lawsuit in the US on Tuesday claiming Eli Lilly, which makes Mounjaro and Zepbound, deployed ad campaigns to "create the misleading impression that Eli Lilly's medicines are superior". Novo said its competitor compared the highest approved doses of its medicines for obesity and type-2 diabetes with lower doses of Novo Nordisk's, while omitting newer, higher-dose options. The lawsuit comes as Novo and Eli Lilly are locked in battle to dominate the fast-growing weight-loss drug industry, especially in the US, which analysts have estimated could be worth more than $100bn by 2030. Novo Nordisk claimed its main competitor in the weight-loss drug business had committed "multiple violations" of federal and state false advertising and unfair competition laws, through its nationwide ad campaigns. The company said Eli Lilly's current campaigns "intentionally" selected outdated studies comparing Lilly's highest doses against lower doses of Novo Nordisk's medicines. It said the ads had "deceptively" presented that Eli Lilly's products were superior, but buried or omitted "critical clinical context". The products being compared incorrectly, according to Novo, were Mounjaro vs. Ozempic and Zepbound vs Wegovy.