Technology & Medicine › Electric age
Insulin
1921–22 (Banting, Best, Collip, Macleod; credit disputed)· Invention or discovery· Germs, drugs & genetics
Mostly agreedGood evidence; some details, dates or numbers uncertain.
The hormone that lets cells take in sugar, extracted in Toronto in 1921–22; it turned type 1 diabetes from fatal to manageable.
See it on the Technology & Medicine map →How it works
Before insulin, children with type 1 diabetes usually died within a year or two, kept alive briefly on starvation diets. In 1921 surgeon Frederick Banting and student Charles Best, in John Macleod's University of Toronto lab, extracted insulin from dog pancreases; biochemist James Collip purified it. In January 1922, 14-year-old Leonard Thompson became the first patient treated. Eli Lilly mass-produced it from pig and cattle pancreases from 1923. Human insulin made by bacteria arrived in 1982.
Why it mattered
Insulin turned a fatal disease into a chronic one and became a model for hormone drugs; millions now depend on it. Its discoverers sold the patent to the university for $1 each.
How we know
Toronto lab notebooks and 1922 papers; Thompson's hospital records; the 1923 Nobel Prize to Banting and Macleod; the University of Toronto's digitized insulin archive.
Still unknown or debated
Credit was bitterly disputed: Banting shared his prize money with Best, and Macleod with Collip. Romanian Nicolae Paulescu published pancreas-extract results months earlier, in 1921.
Connections (3)
▸Insulin was remade by bacteria as Biotech drugs (human insulin)Well documented
The connection
For 60 years insulin was extracted from cattle and pig pancreases. Because it is a small protein whose structure Frederick Sanger had worked out in 1955, it was an ideal first target for genetic engineering. Genentech built synthetic human insulin genes, put them into bacteria, and Eli Lilly sold the result as Humulin from 1982.
When and how
Genentech in South San Francisco and the City of Hope in Duarte, California, August 1978; scaled up by Eli Lilly of Indianapolis and approved in October 1982.
How we know
Genentech's 1979 paper and the FDA's 1982 approval of Humulin, the first drug made with recombinant DNA, document the link directly.
Debates and open questions
Whether human insulin worked better than purified animal insulin is debated; late-1980s complaints that it blunted warning signs of low blood sugar were not confirmed by later studies.
▸Insulin was joined in diabetes care by GLP-1 drugs (Ozempic, Wegovy)Well documented
The connection
Since 1922, insulin injections have replaced the hormone that diabetics lack or cannot use well. GLP-1 drugs work one step earlier: they mimic a gut hormone that prompts the pancreas to release its own insulin when blood sugar rises, and they also curb appetite. Many type 2 patients now take them before or alongside insulin.
When and how
Insulin in Toronto, 1921–22; GLP-1's insulin effect described in the 1980s by teams in Boston, Copenhagen and elsewhere; exenatide approved in the US in 2005.
How we know
Treatment guidelines, such as the American Diabetes Association's, now recommend GLP-1 drugs early; trials compare them directly with insulin.
Debates and open questions
Whether GLP-1 drugs can delay or prevent the need for insulin over the long term in type 2 diabetes is still being studied.
▸Insulin paved the way for hormone drugs like The contraceptive pillMostly agreed
The connection
Insulin's success in the 1920s showed that a hormone could be purified, standardized and sold as an everyday drug, building the modern hormone industry. The Pill applied the same idea to sex hormones: a lab-made progestin mimics the hormone signals of pregnancy, so the ovaries stop releasing eggs.
When and how
Insulin in Toronto, 1921–22; the Pill developed by Pincus and Chang in Shrewsbury, Massachusetts, and Rock near Boston in the 1950s, using progestins made in Mexico City and near Chicago.
How sure are we?
The link is indirect: histories of endocrinology describe insulin encouraging drug firms to invest in hormones, but the Pill rests on separate steroid chemistry from the 1930s–50s.
Debates and open questions
How much credit goes to insulin specifically, rather than to earlier thyroid and adrenaline drugs and the broader rise of hormone science, is a matter of interpretation.