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

Key Takeaways Spaghetti squash has a low glycemic index, meaning it is broken down more slowly and causes a gradual rise in blood sugar and insulin levels. —Heather Jones, Verywell Health, 16 Apr. 2026

This type of movement can improve cardiovascular fitness, increase insulin sensitivity and support metabolic health more efficiently than lower-intensity activity alone. —Katia Hetter, CNN Money, 15 Apr. 2026

His clinic found excessive insulin was trapping his body in a fat-storage cycle that no amount of dieting would have broken. —Allison Palmer, Miami Herald, 10 Apr. 2026

Standard panels routinely skip A1C, fasting insulin, testosterone and thyroid. —Allison Palmer, Fort Worth Star-Telegram, 10 Apr. 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