Leonard Thompson 1908–1935 is the first person to have received injection of insulin as a treatment for Type 1 diabetes.
Thompson received his first injection in Toronto, Ontario, on January 11, 1922, at 14 years of age. The first injection had an apparent impurity which was the likely cause for the allergic reaction he displayed. After a refined process was developed by James Collip to improve the beef-pancreas extract, the second dosage was successfully delivered to the young patient twelve days after the first.
Thompson showed signs of improved health and went on to live 13 more years taking doses of insulin, eventually dying of pneumonia at age 27.
Until insulin was made clinically available, a diagnosis of Type 1 diabetes was an invariable death sentence, more or less quickly usually within months, and frequently within weeks or days.