When Was Insulin First Used to Treat Diabetes?

Leonard Thompson, a 14-year-old boy dying of type 1 diabetes, received the first insulin injection at Toronto General Hospital on January 11, 1922. The initial extract, prepared by Frederick Banting and Charles Best, caused a severe allergic reaction. Biochemist James Collip then purified the extract, and a second injection on January 23 dramatically lowered Thompson's blood sugar with no adverse effects. Before insulin, a type 1 diabetes diagnosis was essentially a death sentence — patients survived at most a year or two on starvation diets. Banting and lab director J.J.R. Macleod received the 1923 Nobel Prize in Physiology or Medicine.