Insulin is a scientific coinage from 1922, built from Latin insula, meaning island, plus the chemical suffix -in. The name refers to the islets of Langerhans, the clusters of hormone-producing cells scattered throughout the pancreas like tiny islands in a sea of exocrine tissue. Paul Langerhans, a German medical student, first described these cell clusters in 1869, and the anatomical metaphor of islands provided the basis for the hormone's eventual name.
The Latin word insula, meaning island, has an uncertain deeper etymology. Some scholars connect it to a presumed form *en-sala, related to salum, meaning the open sea, which would make an island etymologically something in the sea. Others consider insula a pre-Latin substrate word without Indo-European ancestry. Whatever its ultimate origin, insula generated a productive family of English words: insular (relating to an island), insulate (to make into an island, hence to isolate), isle (through Old French from the same Latin source), and peninsula (from paene + insula, meaning almost an island).
The naming of insulin involved several independent proposals converging on the same Latin root. The Belgian physician Jean de Meyer suggested the name insuline in 1909 for a hypothetical pancreatic substance that regulated blood sugar, years before anyone had isolated it. Edward Albert Sharpey-Schafer, a British physiologist, independently proposed the same name in 1916. When Frederick Banting and Charles Best, working at the University of Toronto, successfully isolated the hormone in 1921 and 1922, the name insulin was already waiting.
The isolation of insulin represents one of the most consequential episodes in the history of medicine. Before 1922, a diagnosis of type 1 diabetes was a death sentence, typically within months. The first human patient to receive insulin was Leonard Thompson, a 14-year-old boy in Toronto, who received his initial injection on January 11, 1922. The results were dramatic: patients near death
Banting and Best's decision to sell their insulin patent to the University of Toronto for one dollar each has become one of the most cited examples of medical altruism. Banting's reported statement that insulin does not belong to me, it belongs to the world, established a principle that the discoverers believed should govern access to life-saving medicines. The subsequent commercial history of insulin, including the consolidation of production among a small number of pharmaceutical companies and the sharp escalation of prices in the 21st century, provides a complex counterpoint to this founding gesture.
In modern English, insulin appears primarily in medical and scientific contexts. It refers both to the naturally occurring hormone produced by pancreatic beta cells and to the pharmaceutical preparations administered to diabetic patients. The word has not developed significant figurative meanings, remaining firmly within its scientific register. Its pronunciation follows standard English phonological patterns, with stress on the first syllable. The word's construction from Latin elements using standard scientific naming conventions places it in the same category as other hormone names coined in the early 20th century, such as adrenaline (from Latin ad + renes, near the kidneys