insulin

noun

in·​su·​lin ˈin(t)-s(ə-)lən 

: a protein pancreatic hormone secreted by the beta cells of the islets of Langerhans that is essential especially for the metabolism of carbohydrates and the regulation of glucose levels in the blood and that when insufficiently produced results in diabetes mellitus

Examples of insulin in a Sentence

Recent Examples on the Web

People with Type 1 diabetes are unable to produce insulin, a hormone responsible for regulating blood sugar and supplying cells with glucose for energy. —Noah Lyons, San Diego Union-Tribune, 8 May 2026

The patient felt intimidated by the technology — an insulin pump, a glucose monitor — that would now be part of her daily life. —Nancy Badertscher, AJC.com, 7 May 2026

Your insulin sensitivity is worse at nighttime. —Sohaib Imtiaz, Verywell Health, 4 May 2026

When a dog or a person becomes less sensitive to insulin, brain decay can set in quicker, and the operations of neurons can be scrambled. —Ross Andersen, The Atlantic, 2 May 2026

Word History

Etymology

New Latin insula islet (of Langerhans), from Latin, island

First Known Use

1914, in the meaning defined above

Phrases Containing insulin

• insulin-dependent diabetes
• insulin-dependent diabetes mellitus
• insulin-like growth factor
• insulin resistance
• insulin resistance syndrome
• insulin shock
• non-insulin-dependent diabetes
• non-insulin-dependent diabetes mellitus

Kids Definition

insulin

noun

in·​su·​lin ˈin(t)-s(ə-)lən 

: a hormone that is produced by the pancreas and is necessary for the normal use of glucose by the body

Medical Definition

insulin

noun

in·​su·​lin ˈin(t)-s(ə-)lən 

: a protein hormone that is synthesized in the pancreas from proinsulin and secreted by the beta cells of the islets of Langerhans, that is essential for the metabolism of carbohydrates, lipids, and proteins, that regulates blood sugar levels by facilitating the uptake of glucose into tissues, by promoting its conversion into glycogen, fatty acids, and triglycerides, and by reducing the release of glucose from the liver, and that when produced in insufficient quantities results in diabetes mellitus see iletin