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The very first insulin injection to treat diabetes

Leonard Thompson | January 23, 1922

By: UMass Diabetes Center of Excellence


On January 23, 1922, 14-year-old Leonard Thompson became the first person to receive an insulin injection as treatment for diabetes. By the early 1920s, many researchers strongly suspected that diabetes was caused by a malfunction in the digestive system related to the pancreas gland. At that time, the only way to treat the fatal disease was through a diet low in carbohydrates and sugar, and high in fat and protein. That diet allowed people diagnosed with diabetes to live for about another year. 

Frederick Banting and Charles Best

A breakthrough came at the University of Toronto in the summer of 1921, when Canadians Frederick Banting and Charles Best successfully isolated insulin from canine test subjects, produced diabetic symptoms in the animals, and then began a program of insulin injections that returned the dogs to normalcy. Their discovery was announced to the world on November 14, 1921.

Two months later, with the support of J.J.R. MacLeod of the University of Toronto, the two scientists began preparations for an insulin treatment of a human subject. With the help of biochemist J.B. Collip, they extracted a reasonably pure formula of insulin from the pancreas of cattle from slaughterhouses, and used it to treat Leonard Thompson. The Canadian teenager improved dramatically, and the University of Toronto immediately gave pharmaceutical companies license to produce insulin, free of royalties.

By 1923, insulin had become widely available, saving countless lives around the world, and Banting and Macleod were awarded the Nobel Prize in Medicine.

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