The discovery of insulin is usually credited to a small Canadian team led by Sir Frederick G. Banting and Charles H. Best, working under John J. R. Macleod at the University of Toronto in 1921, with crucial purification work by biochemist James B. Collip.

Quick Scoop: Who discovered insulin?

  • The core answer to “who discovered insulin?” is: Sir Frederick Banting and Charles Best in 1921 in Toronto, Canada.
  • They worked in Macleod’s physiology lab at the University of Toronto, which provided the facilities, funding, and scientific supervision.
  • James Collip later developed a purer, safer form of insulin suitable for human use, which turned the lab discovery into a real treatment.

How the discovery unfolded (mini‑story)

In 1920, Banting read an article about the pancreas and had the idea that if most of the pancreas tissue could be destroyed while sparing the insulin‑producing islet cells, insulin might be extracted in a usable form. He took this idea to John Macleod, who was skeptical at first but eventually gave him lab space, dogs for experiments, and a student assistant—Charles Best.

Banting and Best tied off the pancreatic ducts in dogs so the digestive part of the pancreas would degenerate, then removed the atrophied pancreas and made an extract from the remaining tissue. When they injected this extract into diabetic dogs (whose pancreases had been removed), the animals’ blood sugar levels fell and their symptoms improved, proving the extract contained the life‑saving hormone later named insulin.

Macleod then expanded resources for the project, and Collip joined to purify insulin, making it safe enough for human trials. In early 1922, the team treated a boy with severe diabetes, and his dramatic improvement showed that insulin could transform what had been a fatal disease into a treatable one.

Why the “who” is a bit debated

  • Banting and Macleod received the 1923 Nobel Prize in Physiology or Medicine for the discovery of insulin, and Banting informally shared his prize money with Best, while Macleod shared with Collip.
  • Many historical discussions and modern “who discovered insulin?” articles now explicitly name all four: Banting, Best, Collip, and Macleod.
  • Earlier European researchers had come close to isolating insulin but were held back by war and technical limits, which is why the Toronto team became the first to announce a successful, usable insulin preparation.

Today’s perspective and “latest news” angle

Around the 100th anniversary (2021–2024), there has been renewed attention to the story, including commemorative events, stamps, and historical essays revisiting who gets credit for the discovery of insulin. Modern discussions sometimes emphasize that insulin’s discovery was not a single “eureka” moment but the result of decades of groundwork plus the intense 1921–1922 experiments in Toronto.

In short: insulin was discovered in 1921 by Sir Frederick Banting and Charles Best at the University of Toronto, under John Macleod’s direction and with James Collip’s purification work, turning a deadly disease into a manageable one.

Information gathered from public forums or data available on the internet and portrayed here.