Shares of Eli Lilly (NYSE:LLY) are down 7.6% today, reflecting market disappointment in the company's adjusted guidance for the fourth quarter of 2024. The pharmaceutical giant expects only $13.5 billion in revenue for Q4 2024, compared to the consensus estimate of $13.97 billion.

The main reason for the outlook change is slower-than-anticipated growth in the U.S. incretin market, or in other words, the weight-loss medication industry. Both companies are competing in GLP-1 (Glucagon-like Peptide-1) receptor agonists that help in promoting weight loss.

BioSpace reported that Eli Lilly faces fierce competition from Novo Nordisk (NYSE:NVO)'s Wegovy and Ozempic, which has led to lower-than-expected demand for Eli Lilly's weight loss and diabetes medications, Mounjaro and Zepbound.

While Eli Lilly's Mounjaro and Zepbound offer better efficacy in clinical trials, but Novo Nordisk's Ozempic and Wegovy outpaces thanks to its superior marketing. Wegovy was reported deliver $2.54 billion in sales last quarter to Novo Nordisk surprising analysts that came with sales estimation of $2.21 billion only. While Eli Lilly's Zepbound generated $1.26 billion in sales, the number is less than anticipated at $1.69 billion.

Eli Lilly also mentioned that they were short on channel inventory levels at year-end that also insist the company to lower the guidance for full year 2024.

Nevertheless, Eli Lilly is highly confident about its further development, projecting revenue for 2025 in the range of $58.0 billion to $61.0 billion.