free radical

noun

: an especially reactive atom or group of atoms that has one or more unpaired electrons

especially : one that is produced in the body by natural biological processes or introduced from an outside source (such as tobacco smoke, toxins, or pollutants) and that can damage cells, proteins, and DNA by altering their chemical structure

Examples of free radical in a Sentence

Recent Examples on the Web

May Enhance Cognitive Health Because of their high antioxidant levels, pomegranates may help prevent nerve cell damage caused by reactive compounds called free radicals. —Jillian Kubala, Health, 9 Oct. 2024

The cleanser is infused with a powerful botanical blend that fights off free radicals to keep your skin in tip-top shape. —Brittany Leitner, StyleCaster, 1 Oct. 2024

These health-protective compounds scavenge harmful substances called free radicals that otherwise contribute to inflammation. —Lauren O'Connor, Ms, Health, 2 Oct. 2024

Niacinamide and purslane extract protect your skin from free radicals while vitamin E works to nourish and soften. —Jennifer Hussein, Allure, 2 Oct. 2024

Word History

First Known Use

1870, in the meaning defined above

Medical Definition

free radical

noun

: an especially reactive atom or group of atoms that has one or more unpaired electrons

especially : one that is produced in the body by natural biological processes or introduced from outside (as in tobacco smoke, toxins, or pollutants) and that can damage cells, proteins, and DNA by altering their chemical structure