Insulin Discovered
Banting and Best isolated insulin, revolutionizing treatment of diabetes
October 31, 1921
A Breakthrough That Changed Medicine Forever
In January 1922, a team of scientists at the University of Toronto gave a 14-year-old boy named Leonard Thompson the first-ever injection of insulin. Leonard had Type 1 diabetes and was near death. Within days, his blood sugar dropped to safe levels and he began to recover. The discovery came after years of research by Frederick Banting and Charles Best, who worked through the summer of 1921 to isolate the hormone from the pancreas of dogs. Their supervisor, John Macleod, and chemist James Collip helped purify the extract enough to use on humans safely.
What Insulin Does and Why It Matters
Insulin is a hormone that helps your body turn sugar from food into energy. Without it, sugar builds up in the blood and slowly damages organs. Before insulin was available, a diabetes diagnosis was essentially a death sentence. Doctors could only slow the disease by putting patients on near-starvation diets. The discovery of insulin transformed diabetes from a fatal illness into a manageable condition. Eli Lilly began mass-producing insulin in 1923, making it available to patients around the world.
A Legacy That Still Saves Lives Today
Frederick Banting and John Macleod received the Nobel Prize in Physiology or Medicine in 1923, just two years after the breakthrough. Banting famously shared his prize money with Charles Best, and Macleod shared his with James Collip. Today, over 500 million people worldwide live with diabetes, and insulin remains one of the most essential medicines on the planet. Modern versions are made using genetically engineered bacteria, making production faster and more consistent than ever before. The discovery of insulin is widely considered one of the greatest medical achievements of the 20th century.