New! Sign up for our free email newsletter.
Reference Terms
from Wikipedia, the free encyclopedia

Antioxidant

An antioxidant is a chemical that reduces the rate of particular oxidation reactions in a specific context, where oxidation reactions are chemical reactions that involve the transfer of electrons from a substance to an oxidizing agent, this generally results in different chemicals to the original ones.

Antioxidants are particularly important in the context of organic chemistry and biology. All living organisms maintain a reducing environment inside their cells, all cells contain complex systems of antioxidants to prevent chemical damage to the cells' components by oxidation. These antioxidants include glutathione and ascorbic acid and are substrates for enzymes such as peroxidases and oxidoreductases.

Antioxidants are widely used as ingredients in dietary supplements used for health purposes such as preventing cancer and heart disease. Studies have suggested antioxidant supplements has benefits for health, but several large clinical trials did not demonstrate a definite benefit for the formulations tested, and excess supplementation may even be harmful.

Dietary supplementation has few specific antioxidants compared to a broad diet rich in phytonutrients, which will yield thousands of different polyphenol antioxidants available for metabolism.

Related Stories
 


Health & Medicine News

February 11, 2026

Three major reviews commissioned by the World Health Organization find that GLP-1 drugs including tirzepatide (sold as Mounjaro and Zepbound), semaglutide (Ozempic and Wegovy), and liraglutide ...
Depression in older adults may sometimes signal the early stages of Parkinson’s disease or Lewy body dementia. Researchers found that depression often appears years before diagnosis and remains ...
A cooler bedroom might be better for older sleepers than previously thought. Researchers found that keeping nighttime temperatures at 75°F reduced stress responses and helped the heart work more efficiently during sleep. Hot nights usually force ...
Blood vessels twist, branch, narrow, and balloon in ways that dramatically affect how blood flows — but most lab models have long treated them like straight pipes. Researchers at Texas A&M have now built a new kind of “vessel-chip” that ...
Why does the same virus barely faze one person while sending another to the hospital? New research shows the answer lies in a molecular record etched into our immune cells by both our genes and our life experiences. Scientists at the Salk Institute ...
Ultra-processed foods are everywhere in the American diet, and researchers are finding alarming consequences. Using national health data, scientists found that adults with the highest intake of these foods had a 47% higher risk of heart attack or ...
Scientists have uncovered a surprising way tumors turn the immune system to their advantage. Researchers at the University of Geneva found that neutrophils—normally frontline defenders against infection—can be reprogrammed inside tumors to fuel ...
Human evolution has long been tied to growing brain size, and new research suggests prenatal hormones may have played a surprising role. By studying the relative lengths of index and ring fingers — a clue to oestrogen and testosterone exposure in ...
Autism has long been thought of as a condition that mostly affects boys, but a massive study from Sweden suggests that idea may be misleading. Tracking nearly 3 million people over decades, researchers found that while boys are diagnosed more often ...
A large U.S. study suggests that not getting enough lycopene—the antioxidant that gives tomatoes their red color—may seriously raise the risk of severe gum disease in older adults. Researchers found that seniors with adequate lycopene intake had ...
A sweeping new review of ADHD treatments—drawing on more than 200 meta-analyses—cuts through years of mixed messaging and hype. To make sense of it all, researchers have launched an interactive, public website that lets people with ADHD and ...
Researchers at the University of Michigan have created an AI system that can interpret brain MRI scans in just seconds, accurately identifying a wide range of neurological conditions and determining which cases need urgent care. Trained on hundreds ...

Latest Headlines

updated 12:56 pm ET