Insulin discovery and its impact on diabetes care

In 1921 researchers at the University of Toronto—Frederick Banting, Charles Best, John Macleod and James Collip—isolated insulin, a pancreatic hormone that regulates blood sugar. The first human trial in January 1922 on 14‑year‑old Leonard Thompson dramatically lowered his glucose levels and restored his health, turning diabetes from a fatal disease into a manageable condition.

The patent was sold to the university for a symbolic $1 and production was licensed to Eli Lilly. Over the ensuing century insulin evolved from animal extracts to genetically engineered human and analogue forms, while delivery progressed from syringes to pens, pumps, continuous‑glucose monitors and automated insulin‑delivery systems. These advances have improved control and quality of life for millions of patients.

Despite a century of progress, diabetes remains a major global health challenge, with estimates of over 800 million people living with the disease, many undiagnosed. Rising obesity and lifestyle factors continue to generate new cases, and access to affordable insulin remains limited in some low‑income regions, highlighting ongoing needs for prevention, early detection and equitable treatment.