By his early twenties, Charles Herbert Best had accomplished more for the field of medicine than many have in their entire lifetime.

Born in West Pembroke, Maine, Best enrolled at the University of Toronto to study medicine and had just completed his Bachelor’s degree in Physiology and Biochemistry in 1921 when he landed a summer position as a student assistant in the laboratory of Dr. John James Rickard MacLeod. At the time, Dr. Frederick Banting had just arrived in the city to investigate pancreatic secretions, which he believed to be key in regulating metabolism. MacLeod enlisted Best and another student, Edward Clark Noble, to help Banting. A coin toss decided that Best would start first.

Banting’s work involved isolating extracts of dog pancreas and injecting them into dogs with diabetes. Best was assigned to perform blood-sugar and other biochemical tests, as well as assist with surgical procedures. It did not make sense to switch students midway so Best remained on the project. That summer in the laboratory was unpleasantly hot and cramped. Tensions rose when Banting chided Best and demanded better out of his student, but their working relationship afterwards was largely amicable and productive. Best was able to develop a crude pancreatic extract in January 1922 that was administered to a 14-year-old boy living with diabetes named Leonard Thomson. This treatment was able to lower Thomson’s blood sugar but disappointingly produced minimal improvement to the condition. At Banting’s behest (and to Best’s chagrin), MacLeod added another member to the team, James Collip, who was able to successfully produce a pure isolation of the insulin solution.

The celebration did not last long as Collip lost the ability to recapitulate this process a few weeks later. That, along with concerns over MacLeod and Collip stealing credit for his work, put Banting under immense pressure. At this time, Best stepped in to stifle confrontation and support his mentor. Eventually, Best and MacLeod were able to develop a small amount of potent purified insulin, which successfully treated diabetes in patients.

This began the production of insulin by the University of Toronto’s Connaught Antitoxin Laboratories, in collaboration with the Indiana-based Eli Lilly and Company. Best was made Director of the Insulin Division for Connaught shortly after he completed his Master’s degree at the University of Toronto in 1923. He went on to obtain a Bachelor's Degree in Medicine, again from the University of Toronto, and a Doctorate from the University of London. He eventually returned to Toronto and succeeded MacLeod in 1929 as Professor and Chairman of the Department of Physiology.

Best’s career as a researcher encompassed more than just insulin and diabetes. He studied the physiology of Olympic athletes, the dietary factor choline, and developed procedures for the purification of heparin. During World War II, Best researched night vision and motion sickness, as well as blood transfusions, for soldiers in battle. He did eventually return to his insulin roots, co-founding the Canadian Diabetes Association and attracting top tier diabetes researchers to Toronto.

The Nobel Prize in Physiology or Medicine was awarded jointly to Banting and MacLeod in 1923 for the discovery of insulin. Best’s exclusion was controversial, with Banting publicly stating disappointment (almost rejecting the award altogether!) and sharing his Nobel prize money with his former student.

Best’s long and illustrious career was honoured by the University of Toronto with the unveiling of the Charles H. Best Institute in 1953, located next to the Banting Institute which opened 23 years earlier.

— Written by Angela Zhou