free radical

noun

Definition of free radical

: 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

Polluted air contains a host of tiny particles, like dirt and sulfur dioxide, that create free radicals on skin. — Nikki Krecicki, Allure, "7 Reasons Your Skin Looks Dull — and How to Get a Glowing Complexion," 8 June 2019 That both fuels your cells to proliferate and allows your body to absorb and neutralize more free radicals. — A.a. Newton, SELF, "Here’s What Niacinamide Can—and Can’t—Do for Your Skin," 8 May 2019 Antioxidants neutralize those free radicals to protect your skin from damage. — Chloe Metzger, Marie Claire, "What Do Antioxidants Really Do for Your Skin?," 20 July 2018 The vitamin C serum is packed with its namesake ingredient, as well as antioxidants to protect your skin from free radicals. — Meagan Fredette, Teen Vogue, "Does KylieSkin Care Live Up To The Hype?," 22 May 2019 Look for options that are high in natural antioxidants and polyphenols, which give the body’s defense systems a hand by helping to negate the damage caused by harmful molecules called free radicals. — Emily Abbate, GQ, "4 Simple Ways to Prevent Lower Back Pain from Ruining Your Life," 29 Mar. 2018 Also, its antioxidant properties protect your skin from free radicals and other environmental aggressors that could trigger the formation of fine lines, wrinkles, and even skin cancer, Marchbein adds. — Devon Abelman, Allure, "Why You’re Seeing Ginseng in So Many Korean Skin-Care Products Right Now," 8 Mar. 2019 Libby says when used in skincare, rose water will help our skin combat harmful free radicals and damage caused by UV rays, pollution, and stress. — Audrey Noble, Harper's BAZAAR, "The Beauty Benefits of Rose Water," 8 Feb. 2019 One reason direct physical contact with the ground might have beneficial physiological effects is the earth's surface has a negative charge and is constantly generating electrons that could neutralize free radicals, acting as antioxidants. — Carrie Dennett, chicagotribune.com, "Could walking barefoot on grass improve your health? Some science suggests it can.," 11 July 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'free radical.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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17 Jun 2019

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The first known use of free radical was in 1870

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free radical

noun

Medical Definition of free radical

: 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