Celebrating a centenary : Discovery of Insulin

- 100 years since the discovery of insulin!! -

The year was 1921.

Sir Frederick G Banting (pictured), Charles H Best and JJR Macleod at the University of Toronto discovered insulin!

Insulin was later purified by James B Collip.

Insulin was one of the most profound discoveries of the 20th century and to this day,insulin still remains the only effective treatment for type 1 diabetes.

Countless lives were saved thanks to the discovery of insulin! Before that,diabetic patients who would manage to survive more than a year or two would be considered lucky!

A snapshot of the sequence of events that led to the discovery of insulin and beyond!

7 November 1920

Frederick Banting,a Canadian surgeon paid a visit to Professor John Macleod of the University of Toronto to discuss a plan involving insulin after he had read an article which suggested that insulin-producing cells in the pancreas are slower to deteriorate than other pancreas tissue. Banting visited Macloed because he wasn’t a scientist and so,he couldn’t test this theory on his own.

17 May 1921

Banting and Macleod first got together to begin their research and set about figuring out how to remove insulin from a dog’s pancreas. They brought in research student Charles Best to assist with their research. Their method involved tying off the pancreatic duct to kill off other substances in the pancreas that would destroy insulin, but leave the islets intact. The remaining extract would then be given to other dogs who didn’t produce any of their own insulin because their pancreases had been removed to work out its effects on their blood sugar levels.

10 November 2021

The progress was initially slow and while many of their experiments failed, Banting and the team saw regular drops in blood sugar levels as a result of their extract, and were confident they were on to something big. After many trials, they finally and successfully treated a dog with diabetes with their insulin extract for 70 days!

12 December 1921
James Collip, a biochemist, joined the group to work on purifying insulin so it would be safe enough to be tested in humans. With his help, a more concentrated and pure form of insulin was developed, this time from the pancreases of cattle.

11 January 1922
In January 1922, Leonard Thompson, a 14-year-old boy dying from type 1 diabetes, became the first person to receive an injection of insulin. Within 24 hours, Leonard’s dangerously high blood sugar levels dropped, but he developed an abscess at the site of the injection and still had high levels of ketones.
Collip worked day and night on purifying the extract even further, and Leonard was given a second injection on 23 January 1922. This time it was a complete success and Leonard’s blood sugar levels became near-normal, with no obvious side effects. For the first time in history, type 1 diabetes was not a death sentence.
May 1922 As news of insulin’s success spread, demand rocketed. Banting and Best set about improving their techniques for the production of insulin so it could be made in much larger quantities. In May 1922, Eli Lilly became the first manufacturer to mass produce insulin.
25 October 1923 – a Nobel Prize win! In recognition of their life-saving discovery, Banting and Macleod were jointly awarded the 1923 Nobel Prize in Physiology or Medicine. Banting split his half of the Prize money with Best, and Macleod split the other half of the Prize money with Collip.

Insulin was a very important discovery for mankind! Currently, genetic engineering is being used to produce more insulin quickly by inserting the human insulin gene into bacterial plasmids. These bacteria will reproduce but will have the insulin gene within their plasmids. The insulin gene is then ‘cut’ out using restriction enzymes and injected into diabetic patients! This just goes to show how far away insulin research and advancements have come!


  • The Diabetes UK Website


Saturday Quiz #4 at 2pm (GMT) , 9pm (MYT)

This article was prepared by Eldrian Tho Jiat Yang (he/him)

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