The Story of Insulin

The Story of Insulin

The story of how insulin was discovered isn’t only significant because of the resulting clinical advancements. 

This story also encompasses the ethos of our work at Banting. The team who discovered insulin believed that this life essential medication belonged to the world, not to profit pharmaceutical companies. That’s why at Banting we honor the same values that the scientists who discovered insulin did.  


On July 27th, 1921 Canadian scientists Frederick Banting and Charles Best successfully isolated insulin. Within a year, insulin treatments were already being administered to people living with diabetes, and countless lives were saved from what was known as a fatal disease.


Diabetes was first described 3500 BCE in Ancient Egypt. It was sometimes diagnosed by testing if ants would be attracted to a person’s urine, and by examining certain states of urine. It wasn’t until 1841 that the first clinical test to measure excess glucose in urine was developed, and the Oral Glucose Tolerance Test (now considered the gold standard) wasn’t introduced until 1922.

The exact cause of diabetes also remained a mystery until the 19th century when two physiologists removed the pancreas from a dog. Researchers who had initially thought that diabetes was a kidney disorder finally recognized that diabetes was a metabolic disorder caused by malfunction in the pancreas. 

Before the discovery of insulin, diabetes was treated by exercise and a variety of diets. Some diets aimed to limit carbohydrates, but increase fat and protein. One diet was called the starvation diet, which limits a person’s diet to around 400 calories a day! Even at best, these measures still provided bad prognosis and little time…


Not long before Banting discovered insulin, Sir Edward Albert Sharpey-Shafer hypothesized that the islets of Langerhans (cell type in the pancreas) were a key component of the pancreas’ effect on blood glucose levels. He also pointed to a substance he termed “insuline” as a crucial part of understanding diabetes. 

At the time, scientists were inducing diabetes in animals, and trying to extract insulin from another healthy animal. That insulin was then administered as potential treatment. This method only yielded trace amounts of insulin that also appeared to have harmful side effects due to its toxic properties. 

In 1921 Banting requested laboratory space from the Head of Physiology, Rickard Macleod at the University of Toronto to conduct his own research on islet cells. 

Banting took on an assistant, Charles Best, and sought out a different way to isolate insulin. 

Instead of following the same method, Banting decided to try a new approach that focused on the insulin-producing cells themselves. When the insulin from this approach was injected into diabetic animals, Banting and Best saw that blood glucose levels were decreasing. 

Excited about these findings, Banting and Best continued to optimize their methods to be able to extract and purify insulin in larger quantities in hopes of finding a wide scale treatment for diabetes. 

Shortly after, James Bertram Collip, a Canadian biochemist was recruited to further purify these insulin extracts. As a promising solution to treat diabetes, Insulin quickly entered its first clinical trial. The trial showed blood glucose levels only decreasing minimally, and other diabetic indicators such as ketone levels staying the same.

Collip worked on further purifying the insulin extract. By January 23rd 1922, the second clinical trial commenced and saw immediate and groundbreaking success. 

Realizing that this discovery of life-essential medication was going to alter the treatment and prognosis of diabetes forever, Banting sold the patent for diabetes for $1 and gave pharmaceutical companies the license to produce insulin, as he famously said “Insulin doesn’t belong to me, it belongs to the world.” 

By 1923, Banting and MacLeod were nominated for a Nobel prize in medicine and won. Insulin had become widely available, and the world ushered into a new era of clinical advancements. 

Now, 99 years later, millions of people are able to live long, healthy lives thanks to the work of Dr. Banting. Just as he fought to keep insulin accessible, we at Banting are advocating for you to have access to more affordable insulin. After all, Insulin belongs to the world!


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