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

Its antioxidant effects also protect insulin-producing cells in the pancreas from damage. —Lindsay Curtis, Health, 16 Feb. 2026

Harder’s priorities include cutting health care costs, including how much people pay for prescription drugs like insulin, and to repeal gas taxes in Washington and California. —William Melhado, Sacbee.com, 15 Feb. 2026

Basic, life-saving medications like insulin and routine treatments must remain affordable for all Americans. —Rachel Royster, Fort Worth Star-Telegram, 14 Feb. 2026

When the estrogen hormone declines during perimenopause, the body’s insulin sensitivity decreases, too, which affects overall metabolism. —Alexa Mikhail, Flow Space, 13 Feb. 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