Insulin was not invented by a single person; it was discovered in 1921 by a Canadian team led by Sir Frederick Banting and Charles Best, under the direction of John J. R. Macleod, with crucial purification work by James Collip.

Quick Scoop

  • The core answer to “who invented insulin” is usually given as Frederick Banting and Charles Best.
  • Historically, however, insulin is credited to a team effort at the University of Toronto:
    • Sir Frederick G. Banting – originator of the key experimental idea and lead researcher.
* Charles H. Best – medical student who carried out much of the lab work with Banting.

* J. J. R. Macleod – senior physiologist who provided the lab, funding, and scientific guidance.

* James B. Collip – biochemist who purified insulin so it could be used safely in humans.
  • In 1923, Banting and Macleod received the Nobel Prize in Physiology or Medicine for the discovery of insulin, and Banting later shared his prize money with Best, while Macleod shared with Collip.

A tiny story snapshot

Before insulin, a diagnosis of type 1 diabetes was essentially a death sentence, and patients were often kept alive briefly on extreme starvation diets. In 1921, Banting and Best began experiments on dogs by tying off the pancreatic ducts, letting most of the pancreas waste away while preserving the insulin-producing islets, then extracting a substance that could lower blood sugar. With Macleod’s support and Collip’s purification work, the extract—now named “insulin”—was finally safe enough for humans. In early 1922, a 14‑year‑old boy named Leonard Thompson became the first person to receive insulin treatment and recovered from near-fatal diabetic ketoacidosis, dramatically proving that the discovery worked in real life.

In short: insulin was discovered in 1921 by Banting, Best, Macleod, and Collip in Toronto, and that breakthrough has saved millions of lives worldwide ever since.

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