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

When used together, SPF provides a physical barrier between the skin and UV rays, while Vitamin C helps fight off any free radicals that manage to seep through. —Jenny Berg, Allure, 24 Oct. 2024

Carotenoids are specifically focused on fighting free radicals that can cause cardiovascular diseases, cancer, and eye diseases. —Sara Novak, Discover Magazine, 16 Oct. 2024

The popular serum features 22 plant extracts, including turmeric, which reduces visible signs of aging, sea buckthorn, which fights skin-aging free radicals, Mary’s thistle, which provides nourishment, oat, which tightens, and aloe vera, which soothes. —Ali Faccenda, Peoplemag, 18 Sep. 2024

Brightens skin: Arbutin has antioxidant properties that fight skin-damaging free radicals and oxidative stress, helping to improve the appearance of dull or sallow skin. —Lindsay Curtis, Verywell Health, 13 Sep. 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