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
Vitamin E: Vitamin E can help protect the skin from damage caused by free radicals.
—
Amber Smith, Discover Magazine, 6 Nov. 2023
Almonds, for example, are packed with vitamin E, a potent antioxidant that protects the skin from free radical damage and promotes cell regeneration.
—Daphne Ewing-Chow, Forbes, 29 Feb. 2024
Fueled by exposure to air, light, and heat, unsaturated fats break down and release free radicals.
—Ali Francis, Bon Appétit, 12 Mar. 2024
Several studies show that vitamin C protects and improves skin, helping neutralize free radicals that cause oxidative skin stress, leading to premature aging and reducing the appearance of fine lines and wrinkles.
—Kate Donnelly, Forbes, 29 Feb. 2024
Antioxidants help neutralize the free radicals in our bodies which, when imbalanced, can cause cell damage and lead to disease.
—Clare Mulroy, USA TODAY, 16 Jan. 2024
Vitamin E Vitamin E protects against damage from free radicals and clots and aids in immune function.
—Allison Futterman, Discover Magazine, 16 Feb. 2024
Oils like apricot kernel, raspberry seed, and rosehip soothe, smoothe, promote cell regeneration, and protect lips from free radicals, all while giving you a semi-pigmented sheen that’s long lasting.
—Stephanie Osmanski, Southern Living, 14 Feb. 2024
So the scientists exposed the tardigrades to different kinds of molecules known to block cysteine oxidation, as scientists call binding by a free radical.
—Meghan Bartels, Scientific American, 17 Jan. 2024
Amber Smith, Discover Magazine, 6 Nov. 2023
Almonds, for example, are packed with vitamin E, a potent antioxidant that protects the skin from free radical damage and promotes cell regeneration.
—Daphne Ewing-Chow, Forbes, 29 Feb. 2024
Fueled by exposure to air, light, and heat, unsaturated fats break down and release free radicals.
—Ali Francis, Bon Appétit, 12 Mar. 2024
Several studies show that vitamin C protects and improves skin, helping neutralize free radicals that cause oxidative skin stress, leading to premature aging and reducing the appearance of fine lines and wrinkles.
—Kate Donnelly, Forbes, 29 Feb. 2024
Antioxidants help neutralize the free radicals in our bodies which, when imbalanced, can cause cell damage and lead to disease.
—Clare Mulroy, USA TODAY, 16 Jan. 2024
Vitamin E Vitamin E protects against damage from free radicals and clots and aids in immune function.
—Allison Futterman, Discover Magazine, 16 Feb. 2024
Oils like apricot kernel, raspberry seed, and rosehip soothe, smoothe, promote cell regeneration, and protect lips from free radicals, all while giving you a semi-pigmented sheen that’s long lasting.
—Stephanie Osmanski, Southern Living, 14 Feb. 2024
So the scientists exposed the tardigrades to different kinds of molecules known to block cysteine oxidation, as scientists call binding by a free radical.
—Meghan Bartels, Scientific American, 17 Jan. 2024
These examples are programmatically compiled from various online sources to illustrate current usage of the word 'free radical.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.
Word History
First Known Use
1870, in the meaning defined above
Dictionary Entries Near free radical
Cite this Entry
“Free radical.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/free%20radical. Accessed 16 Apr. 2024.
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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
More from Merriam-Webster on free radical
Britannica.com: Encyclopedia article about free radical
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