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

While the blend features potent amounts of the aforementioned actives, proteins, peptides, shea butter, ceramides, green tea, and CoQ10 are also featured to protect skin from free radicals, hydrate, and smooth. —Kiana Murden, Vogue, 24 Dec. 2024

This antioxidant trio will help brighten dark spots and protect the skin from free radicals too. —Kristin Canning, SELF, 27 Nov. 2024

Vitamin E can help to protect the cells in the eye from free radicals and thus also reduce their sensitivity to bright light. —Maria Berentzen, Vogue, 12 Dec. 2024

Lilac stem cells also help fight free radicals and curb excess oil production without drying out skin, while two types of marine algae increase hydration and support the skin's natural collagen production. —Jennifer Hussein, Allure, 11 Dec. 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