Eli Lilly ( LLY 0.89%) has been growing its sales at a good clip over the past year. This is partly thanks to Zepbound, a weight loss medicine that's already generating more than $1 billion in quarterly sales, although it was approved only in late 2023.

Eli Lilly said on Wednesday it had sued four compounders for selling unapproved products containing tirzepatide, after a U.S. judge last month blocked pharmacies from making copies of its weight-loss and diabetes medicines.