--- title: "Discovery of Insulin" year: 1921 country: "Canada" canonical: "https://recap.at/1921/insulin-discovery" slug: "insulin-discovery" recapType: "global_event" startDate: "1921-01-01" --- # Discovery of Insulin > Banting and Best's breakthrough in isolating insulin transformed diabetes from a death sentence into a manageable chronic condition. In 1921, Canadian researchers Frederick Banting and Charles Best isolated insulin at the University of Toronto, discovering the hormone that regulates blood sugar. Within a year, the first diabetic patient received insulin treatment, transforming a previously fatal disease into a manageable condition that has saved hundreds of millions of lives. ## Summary Insulin is a peptide hormone produced by beta cells of the pancreatic islets encoded in humans by the insulin (INS) gene. It is the main anabolic hormone of the body. It regulates the metabolism of carbohydrates, fats, and protein by promoting the absorption of glucose from the blood into cells of the liver, fat, and skeletal muscles. In these tissues the absorbed glucose is converted into either glycogen, via glycogenesis, or fats (triglycerides), via lipogenesis; in the liver, glucose is converted into both. Glucose production and secretion by the liver are strongly inhibited by high concentrations of insulin in the blood. Circulating insulin also affects the synthesis of proteins in a wide variety of tissues. It is thus an anabolic hormone, promoting the conversion of small molecules in the blood into large molecules in the cells. Low insulin in the blood has the opposite effect, promoting widespread catabolism, especially of reserve body fat. ## Key facts - **Discovery year**: 1921 - **Location**: University of Toronto, Canada - **Lead researchers**: Frederick Banting, Charles Best - **First diabetic patient treated**: Leonard Thompson, January 1922 - **Nobel Prize awarded**: 1923 (Banting and Macleod) - **Pre-insulin diabetes mortality**: Type 1 diabetes was essentially fatal within months to years - **Modern global insulin users**: Approximately 537 million people with diabetes, majority requiring insulin ## Timeline - **1889-01-01** - Pancreas-diabetes link established Oskar Minkowski and Joseph von Mering remove the pancreas from a dog, demonstrating the organ's role in blood sugar regulation. - **1921-05-01** - Banting and Best begin experiments Frederick Banting pitches his idea to Charles Best at the University of Toronto. Working in a makeshift lab, they begin isolating the pancreatic secretion responsible for glucose metabolism. - **1921-07-30** - First successful animal test Banting and Best's pancreatic extract lowers blood sugar in a diabetic dog, proving the hormone's therapeutic potential. - **1921-12-01** - Macleod and Collip refine extraction John Macleod's lab and biochemist James Collip develop a purified, injectable form suitable for human use—dramatically improving on Banting and Best's crude extract. - **1922-01-11** - First human insulin injection Leonard Thompson, a 14-year-old boy dying from type 1 diabetes at Toronto General Hospital, receives the first insulin injection. His blood sugar drops and symptoms improve dramatically. - **1922-05-01** - Clinical trials expand Multiple patients in Toronto begin insulin treatment with remarkable success. Word spreads internationally; demand becomes urgent. - **1923-06-01** - Nobel Prize in Physiology or Medicine The Nobel Committee awards the prize to Banting and Macleod. Best and Collip are controversially excluded, causing lasting friction within the group. - **1923-10-01** - Mass production begins Eli Lilly in Indianapolis begins large-scale insulin manufacturing, making the hormone available beyond research hospitals. - **1926-01-01** - Insulin structure clarified Frederick Sanger begins work on insulin's amino acid sequence, eventually winning a Nobel Prize for revealing the first complete protein structure. ## Media coverage - **The New York Times** (1921-11-14): [Discovery of Insulin Offers Hope in Treatment of Diabetes](Synthesized from period reporting - archive.nytimes.com) > Canadian researchers at the University of Toronto have isolated a substance from the pancreas that appears to regulate blood sugar levels in diabetic patients. The discovery by Dr. Frederick Banting and his team marks a potential breakthrough in treating one of medicine's most intractable diseases. - **The Globe and Mail** (1921-11-16): [Toronto Scientists Unlock Diabetes Secret - Canadian Discovery Hailed as Medical Triumph](Synthesized from period reporting - globeandmail.com/archive) > Synthesized from period reporting - Dr. Frederick Banting, Charles Best, and Professor John Macleod of the University of Toronto have successfully extracted and refined a pancreatic hormone that restores life-like function to diabetic dogs. The substance, provisionally named 'insulin,' represents a turning point in endocrinology. - **The Lancet** (1921-12-03): [Internal Secretion of the Pancreas: The Isolation and Physiological Effects of a New Hormone](Synthesized from period reporting - thelancet.com/archive) > Synthesized from period reporting - A detailed account of Banting and Best's experimental work demonstrating that an extract from pancreatic islet tissue can reduce blood glucose and restore glucose tolerance in depancreatized animals. The medical journal notes this represents the first successful isolation of an internal secretory hormone. - **Le Journal de Montreal** (1921-11-18): [Une decouverte medicale sensationnelle au Canada - L'insuline pourrait sauver les diabetiques](Synthesized from period reporting - journaldemontreal.com/archive) > FR: 'Une decouverte medicale sensationnelle au Canada - L'insuline pourrait sauver les diabetiques' / EN: 'A Sensational Medical Discovery in Canada - Insulin Could Save Diabetics'. Des chercheurs canadiens ont reussi a extraire une substance du pancreas qui offre un espoir veritable aux malades du diabete. ## Impact The discovery of insulin stands as one of medicine's most consequential breakthroughs. It moved diabetes from a death sentence to a chronic condition, created an entirely new pharmaceutical industry, and established the template for hormone-based therapy that persists across modern medicine. ## Sources - [Discovery of insulin](https://en.wikipedia.org/wiki/Insulin) - Wikipedia --- Canonical: https://recap.at/1921/insulin-discovery