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 niacinamide works to combat hyperpigmentation, minimize the look of pores, and reduce excess oil production, vitamin C targets discoloration and free radical damage for smoother, more even skin, says Dr. Yadav. —Michelle Rostamian, Allure, 30 Dec. 2024

This helps prevent oxidative stress, which occurs when free radical levels become too high.5 Oxidative stress can increase the risk of health conditions like heart disease and certain cancers. —Jillian Kubala, Health, 29 Dec. 2024

This can lead to the formation of free radicals, which can damage cells in the long term. —Maria Berentzen, Vogue, 12 Dec. 2024

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

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