The two biggest weight-loss drugmakers have lost $252bn in value this year, as investor enthusiasm for obesity treatments wanes and Donald Trump’s tariff and price-cut threats weigh on the pharmaceutical sector.

Eli Lilly will significantly increase the price of its weight-loss drug Mounjaro in the United Kingdom in a bid to bring down prices in the United States after weeks of pressure from the Trump administration.

Eli Lilly's new oral GLP-1 medication orforglipron produced an average weight loss of 12.4% (27.3 pounds) in clinical trials. The weight loss pill also significantly improved heart health markers like cholesterol and blood pressure.