Eli Lilly became the first company to produce insulin on an industrial scale in the 1920s.
After researchers at the University of Toronto demonstrated insulin’s therapeutic potential in 1922, Eli Lilly worked with the researchers to develop a reliable manufacturing process. The company produced Iletin, an early commercial insulin preparation, helping make treatment available to many more people with diabetes.
Before insulin, type 1 diabetes was usually fatal, and treatment options were extremely limited. Industrial production required extracting and purifying insulin from animal pancreases while maintaining consistent potency. Lilly’s work helped transform a laboratory discovery into a practical medicine.
This history is sometimes confused with the discovery itself. Frederick Banting, Charles Best, James Collip, and John Macleod were central to the Toronto research, while Eli Lilly was a commercial manufacturer and development partner. Modern insulin products are often recombinant rather than animal-derived.