Novo Nordisk is to invest more than $4bn (£3.2bn) in US manufacturing as it battles to keep up with booming demand for its obesity and diabetes drugs Wegovy and Ozempic. Denmark’s biggest pharmaceuticals company said it would spend $4.1bn building a second filling and finishing facility in Clayton, North Carolina, one of the biggest manufacturing investments in its history. Its drugs are injected by users once a week, and come in pre-filled pens. The facility, which will have roof-top solar panels, will double the space of Novo Nordisk’s three existing facilities in North Carolina, and add 1,000 jobs, on top of the nearly 2,500 people already working for the drugmaker in the state. The company’s president and chief executive, Lars Fruergaard Jørgensen, said: “It took us a century to reach 40 million patients, but through this expansion and continued investment in our global production, we’re building Novo Nordisk’s ability to serve millions more people living with serious chronic diseases in the future. “This is yet another real signal of our efforts to scale up our production to meet the growing global need for our life-changing medicines and the patients of tomorrow.” Overall, Novo Nordisk plans to invest $6.8bn in production this year compared with $3.9bn last year, to increase supply of its injectable drugs. Wegovy and Ozempic have become hugely popular amid an obesity crisis in many countries, which led to shortages and the company rationing the use of them. The medicines have been endorsed by celebrities such as Oprah Winfrey and Elon Musk, although others such as the US comedian Amy Schumer have said they stopped taking Ozempic because of the side-effects. The success of its drugs has led to an 84% increase in Novo Nordisk shares in the past year, making it Europe’s most valuable company and its market value more than the entire Danish economy. Henrik Wulff, the firm’s executive vice-president for product supply, quality and IT, said: “Clayton was the first manufacturing site for Novo Nordisk in the US, and this new large-scale investment confirms the continued importance of our production facilities there as cornerstones of our company’s growth.” Wegovy and Ozempic are part of a new class of weight-loss and diabetes drugs known as GLP-1, which mimic the action of a gut hormone and suppress people’s appetite. They have helped some people lose significant amounts of weight but can cause unpleasant side-effects such as nausea. Novo Nordisk and its main competitor, the US drugmaker Eli Lilly, raised their sales forecasts last month. Eli Lilly’s diabetes treatment tirzepatide, marketed as Mounjaro, was approved for obesity at the beginning of this month, giving patients and doctors what the medical regulator said was a more effective alternative to semaglutide, better known as Wegovy.