antioxidant

American  

[an-tee-ok-si-duhnt, an-tahy-] / ˌæn tiˈɒk sɪ dənt, ˌæn taɪ- /

noun

1. Chemistry. any substance that inhibits oxidation, as a substance that inhibits oxidative deterioration of gasoline, rubbers, plastics, soaps, etc.

2. Biochemistry. an enzyme or other organic substance, as vitamin E or beta carotene, that is capable of counteracting the damaging effects of oxidation in animal tissues.

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adjective

1. Chemistry. of or relating to an antioxidant.

antioxidant British  

/ ˌæntɪˈɒksɪdənt /

noun

1. any substance that retards deterioration by oxidation, esp of fats, oils, foods, petroleum products, or rubber

2. biology a substance, such as vitamin C, vitamin E, or beta carotene, that counteracts the damaging effects of oxidation in a living organism

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antioxidant Scientific  

/ ăn′tē-ŏk′sĭ-dənt,ăn′tī- /

1. A chemical compound or substance that inhibits oxidation. Certain vitamins, such as vitamin E, are antioxidants and may protect body cells from damage caused by the oxidative effects of free radicals.

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Etymology

Origin of antioxidant

First recorded in 1925–30; anti- + oxidant ( oxid(ize) + -ant )

Example Sentences

Previous studies have already shown that very high antioxidant intake can have drawbacks.

From Science Daily • Mar. 27, 2026

That’s on top of the injections Leite gives herself regularly: NAD+, which she says makes her feel energized and alleviates her brain fog, and glutathione, which is marketed for antioxidant and immune support.

From The Wall Street Journal • Mar. 18, 2026

Taken together, the evidence indicates that pecans may benefit the heart largely by improving lipid metabolism and strengthening antioxidant defenses.

From Science Daily • Feb. 22, 2026

When the researchers treated stressed skin cells with catalase, a naturally occurring antioxidant enzyme that breaks down hydrogen peroxide, cellular stress levels dropped.

From Science Daily • Jan. 20, 2026

“Just some antioxidant recipes. Ready for BiPAP and America’s Next Top Model?” she asked.

From "The Fault in Our Stars" by John Green