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
By correcting the imbalance between free radicals and antioxidants (referred to as oxidative stress), the polyphenols can improve arterial function and help ease blood pressure.
—
Md Published, Verywell Health, 12 July 2025
Formulated with skin-nourishing ingredients like vitamin C, collagen, and sodium hyaluronate (a sister to hyaluronic acid), the serum reduces signs of aging and supports collagen production, evens your skin complexion, and defends against free radicals.
—Alicia Geigel, Southern Living, 7 July 2025
These nutrients work like cellular firefighters, quenching damaging free radicals and supporting the body's natural repair mechanisms.
—Ximena Araya-Fischel, Forbes.com, 4 July 2025
At high levels, free radicals trigger what’s known as oxidative stress, which can damage cell DNA and increase your risk of conditions like heart disease and diabetes.78
4.
—Cynthia Sass, Health, 23 June 2025
See All Example Sentences for free radical
Examples are automatically compiled from online sources to
show current usage.
Read More
Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
Send us feedback.
Md Published, Verywell Health, 12 July 2025
Formulated with skin-nourishing ingredients like vitamin C, collagen, and sodium hyaluronate (a sister to hyaluronic acid), the serum reduces signs of aging and supports collagen production, evens your skin complexion, and defends against free radicals.
—Alicia Geigel, Southern Living, 7 July 2025
These nutrients work like cellular firefighters, quenching damaging free radicals and supporting the body's natural repair mechanisms.
—Ximena Araya-Fischel, Forbes.com, 4 July 2025
At high levels, free radicals trigger what’s known as oxidative stress, which can damage cell DNA and increase your risk of conditions like heart disease and diabetes.78
4.
—Cynthia Sass, Health, 23 June 2025
See All Example Sentences for free radical
Cite this Entry
“Free radical.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/free%20radical. Accessed 19 Jul. 2025.
Copy CitationLove words? Need even more definitions?
Merriam-Webster unabridged
Share