On October 9, 1923, Frederick Banting, Charles Best, and James Collip were granted the patent for “Extract Obtainable from the Mammalian Pancreas or from the Related Glands in Fishes, Useful in the Treatment of Diabetes Mellitus, and a Method of Preparing It” or Insulin, U.S Patent No. 1,469,994.

Type 1 diabetes (T1D) is an autoimmune disease that occurs when a person does not produce enough or any insulin. Without regulated insulin levels to maintain blood glucose levels, serious health problems can arise.

Before insulin was discovered, diabetes was considered a fatal disease. Typically, T1D is most commonly found in children and adolescents. Before the advancements of modern medicine, those diagnosed with T1D rarely lived a year after the diagnosis and suffered greatly; often with loss of vision, heart attacks, and kidney failure.

Although it is debated who the original discoverers of insulin are, many believe it is orthopedic surgeon, Frederick G. Banting, Dr. Charles Herbert Best, and biochemist, James Bertram Collip. Dr. John Macleod, physiologist, is also credited with helping as he provided a laboratory, cow pancreases for testing purposes, and more.

Dr. John Macleod was born in 1876 in Scotland. He studied medicine at Aberdeen University. Macleod did extensive research on diabetes and concluded that “impaired utilization of sugar was probably the major reason for hyperglycemia in diabetes.”[1] He moved to Toronto and was a Professor of Physiology at the University of Toronto, where he met Banting.

Dr. Frederick Banting was born in 1891 in Ontario, Canada. He studied medicine at the University of Toronto and served in the Canadian Army Medical Corps where he was wounded in the battle of Cambria and received the Military Cross for heroism under fire.  Upon his return from the Army, Banting practiced orthopedic medicine but continued to come back to his most considerable interest, diabetes research.  Banting was determined to discover how to successfully extract insulin from the pancreas before proteolytic enzymes destroyed it. He went to Macleod, who provided facilities to work in and was introduced to Dr. Charles Best.

Dr. Charles Herbert Best was born in 1899 in Maine. He enlisted in the Canadian Army in 1918. He returned from the Army a year later and attended medical school at the University of Toronto. Best was meant to be a summer research assistant for Macleod, but Banting needed help with his experiments so Best became Banting’s assistant. Along with Best, Dr. James Bertram Collip was also an assistant to Banting.

Dr. James Collip was born in 1892 in Ontario, Canada. He attended the University of Toronto at the age of 15 and received his doctorate in biochemistry by the age of 24. In April of 1921, he went to work with Macleod. In December of 1921, Banting and Best were having difficulties with their research so Macleod assigned Collip to work with them. Collip’s contribution was to “prepare insulin in a more pure, usable form than Banting and Best had been able to achieve”[2].

In the initial phases of testing, pancreases from dogs and cattle were used. They removed insulin from the pancreases, but early experiments showed toxic substances in the insulin, which caused adverse irritations and reactions. They went back to the drawing board to research how to extract insulin more purely. In later tests, they removed the pancreas from a dog and injected it with a purer form of insulin and were successful. They found the extract lowered blood glucose levels, and several dogs with diabetes lived due to the extract. According to the patent application, obtaining the pure form of insulin was done by:

“extracting the internal secretion or hormone from the fresh pancreas of Mammalia, or, from the fresh pancreas of cartilaginous fishes, or, from fresh related glands, (principal islets), of bony fishes, with a solvent capable of preserving the activity of the internal secretion or hormone and then separating it practically free from injurious substances including inert associated gland tissue, proteins, proteolytic enzymes, salts and lipoids[3]”

There had been many successful trials with animals, but the first success with a human was with 14-year-old Leonard Thompson. Thompson had type 1 diabetes and was near death when the trial began. The first trial was unsuccessful, but on the second attempt, when given the purer form, Thompson’s blood sugar levels decreased significantly, and he regained his strength and appetite. After perfecting this method, they sold it to the University of Toronto for $1. They wanted insulin to be available to all of those who needed it.

In 1923, Banting and Macleod were awarded the Nobel Prize in Physiology or Medicine. Banting did not agree with Macleod receiving the award as he felt his role was more supervisory and that Best should have been awarded instead. In the end, Banting shared his prize with Best and Macleod shared with Collip.


[1] Diapedia: John Macleod

[2] Wikipedia: James Collip

[3] US Patent 1,469,994


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