Shares of Eli Lilly (LLY) plummeted 5.03% in Tuesday's intraday trading session, as investors reacted to a perfect storm of negative news surrounding the pharmaceutical giant. The stock's decline was primarily driven by President Donald Trump's announcement of impending pharmaceutical tariffs, the company's lowered profit guidance, and unfavorable news regarding its weight loss drug Zepbound.

President Trump declared late Monday that he would unveil tariffs on pharmaceuticals within the next two weeks, reigniting concerns about the potential impact on drug manufacturers. This announcement sent ripples through the pharmaceutical sector, with Eli Lilly being one of the hardest-hit companies. The uncertainty surrounding the level and timing of these tariffs has left investors anxious, contributing to the broader market decline.

Adding to the pressure on Eli Lilly's stock was the company's decision to lower its full-year profit outlook. While Lilly maintained its sales forecast of between $58 billion and $61 billion, it reduced its full-year earnings per share (EPS) guidance to a range of $20.78 to $22.28, down from an earlier outlook of $22.50 to $24. The company attributed this adjustment to acquired in-process research and development charges related to its recent acquisition of Scorpion Therapeutics' STX-478 program for breast cancer treatment.

Furthermore, CVS Health announced that its pharmacy benefit manager unit, Caremark, would make rival Novo Nordisk's weight loss drug Wegovy the preferred medication on its standard formularies, while dropping Eli Lilly's Zepbound. This decision raised concerns about potential pricing pressures and market share challenges for Lilly's GLP-1 drugs, which have been a significant growth driver for the company.

Despite these headwinds, Eli Lilly reported strong first-quarter results, with revenue growing 45% to $12.73 billion and adjusted EPS climbing 29% to $3.34. The company's GLP-1 drugs, Mounjaro and Zepbound, continued to show robust performance. However, the positive earnings report was overshadowed by the aforementioned challenges, leading to the significant stock decline.

As investors digest these developments, all eyes will be on President Trump's upcoming announcement regarding pharmaceutical tariffs and Eli Lilly's ability to navigate the evolving competitive landscape in the weight loss drug market.