Eli Lilly and Co said it will invest more than $700 million to boost its insulin manufacturing capacity in Puerto Rico, France, China and the United States.

The company's traditional stronghold has been its diabetes treatments, but the sales of its drugs have been suffering due to increasing competition from companies including Denmark's Novo Nordisk.

Lilly said on Thursday it will invest $350 million in China, which already has the most diabetics globally and where the number is expected to rise to 142.7 million in 2035 from 98.4 million.