Insulin

The first living creature ever treated with insulin was a pancreatectomized dog named Marjorie in Banting and Best's Toronto lab in July 1921. After her blood sugar plummeted from a fatal 0.20% to normal levels within hours, she lived for months—proof that the extract worked. This single diabetic dog's survival launched human trials just months later, a breathtakingly fast translation that would save countless human lives but would be considered recklessly rapid by today's clinical standards.

Banting and Macleod won the 1923 Nobel Prize in Physiology or Medicine—just two years after the first successful experiments, making it one of the fastest recognitions in Nobel history. Banting was so furious that his student Charles Best wasn't included that he initially threatened to refuse the prize, ultimately splitting his half with Best while Macleod split his with biochemist Collip. This Nobel controversy highlighted the messy reality of collaborative discovery: who deserves credit when breakthrough depends on teamwork?

Banting famously sold the insulin patent to the University of Toronto for $1, declaring it unethical for doctors to profit from life-saving discoveries. Yet a century later, insulin prices in the US have skyrocketed to over $300 per vial—more than 1000% higher than in other developed nations—driving diabetics to ration doses or buy from underground markets. The cruel irony is that Banting's altruistic gesture couldn't prevent the very pharmaceutical profiteering he sought to avoid, as incremental modifications created new patents while the essential medicine remained out of reach for many.

Insulin is essentially your body's cellular doorman, signaling glucose to enter muscle and fat cells after every meal—without it, sugar accumulates lethally in the bloodstream while cells starve. This protein hormone, made of just 51 amino acids arranged in two chains, was the first protein ever sequenced (by Frederick Sanger in 1955, earning another Nobel) and the first produced through genetic engineering in bacteria. That bacteria in industrial vats now manufacture human insulin revolutionized both treatment and biotechnology itself, proving we could reprogram living organisms as pharmaceutical factories.

In January 1922, 14-year-old Leonard Thompson lay dying in Toronto General Hospital, weighing just 65 pounds, when he became the first human to receive insulin therapy. The first injection failed due to impurities, but the refined version 12 days later brought his blood sugar from a fatal 520 mg/dL to near-normal levels—he lived another 13 years. Photos from diabetes wards before 1922 show skeletal children with hollow eyes in metabolic wards doctors called "the morgue"; after insulin, these same institutions transformed into places of hope, one of medicine's most dramatic before-and-after moments.

Think of insulin as your body's metabolic thermostat, constantly adjusting based on real-time feedback: when blood sugar rises, beta cells in your pancreas release insulin within minutes; when it drops, insulin shuts off and glucagon kicks in. This exquisite balancing act happens automatically 24/7, maintaining glucose in a narrow range between 70-100 mg/dL—yet for the 537 million diabetics worldwide, this thermostat is broken, requiring manual adjustment through injections, calculations, and constant vigilance. Understanding insulin reveals why managing diabetes is less like taking antibiotics for an infection and more like manually flying a plane that healthy bodies pilot on autopilot.