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insulin

n.
US //ˈɪnsəɫən// UK //ˈɪnsuːlˌɪn// in·sulin
  1. 1 natural hormone (n.)
    B2 Upper Intermediate Technical Medicine

    a natural substance made by your body that helps you use and store the sugar from food.

    a hormone produced by the islets of Langerhans in the pancreas that regulates the level of glucose in the blood.

    Example

    The body produces insulin to help turn the sugar from your meals into energy.

    Example

    In a healthy individual, the pancreas releases insulin in response to rising blood glucose levels, facilitating the transport of sugar into the cells.

    Usage

    Uncountable when referring to the biological substance in general.
    • glucagon
  2. 2 medication (n.)
    B2 Upper Intermediate Medicine

    a medicine that people with diabetes take to keep their blood sugar at a safe level.

    a pharmaceutical preparation of the hormone, or its synthetic analogues, administered to patients with diabetes mellitus.

    Example

    He needs to take an insulin injection every day before he eats breakfast.

    Example

    Advancements in biotechnology have allowed for the production of rapid-acting insulin analogues that more closely mimic the body's natural response to a meal.

    Usage

    Can be used as a countable noun when referring to specific types or doses of the medication.
Origin

From Latin īnsula (“island”) (named for the islets of Langerhans, where insulin is produced) + -in.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

Last updated June 20, 2026