Eli Lilly Wednesday filed lawsuits against four telehealth companies alleging they are deceiving consumers by selling compounds of slightly-different versions of Lilly drugs.

Pharmaceutical giant Eli Lilly alleges the companies are selling illegal off-brand versions of its best-selling diabetes and weight-loss drugs, Mounjaro and Zepbound.

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.