What Is Oxidative Stress?

Oxidative stress can lead to cell and tissue damage.

Cocoa, grapeseed oil, blueberries, and red grapes

Verywell / Anastasia Tretiak

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Oxidative stress happens when free radicals in your body overwhelm your body's defenses. This imbalance can lead to cell and tissue damage.

In some cases, oxidative stress can be beneficial, such as chemotherapy medications that specifically target cancer cells. In many cases, though, oxidative stress is considered harmful. Scientists have linked oxidative stress to aging and a number of diseases.

Causes of Oxidative Stress

Oxidative stress is caused by free radicals in your cells. Free radicals are unstable molecules with unpaired electrons. In excessive amounts, they can damage your cells by robbing other molecules of their electrons. This process is also called oxidation.

Free radicals can be produced when your body breaks down nutrients to create energy. They are also produced from sources in our environment, including:

  • Smoking
  • Radiation
  • UV light
  • Air pollution
  • Alcohol/drug use


Free radicals are unstable molecules. They can cause oxidative stress when they overwhelm your body's defenses.

Effects of Oxidative Stress

Oxidative stress contributes to the development of many diseases and chronic conditions, including:

  • Age-related macular degeneration: As you age, oxidative stress can lead to vision problems including macular degeneration.
  • Atherosclerosis: In this condition, your arteries harden and narrow with plaque, which includes fat, cholesterol, and other substances. Part of that build-up is due to oxidative stress, which causes inflammation in the arteries.
  • Cancer: Oxidative stress can cause DNA damage to cells, which can lead to cancer.
  • Chronic obstructive pulmonary disease: Oxidative stress can lead to COPD. Cigarette smoke is the most common environmental cause.
  • Diabetes: Oxidative stress contributes to diabetes and its complications, including stroke, kidney disease, and retina damage.
  • Glaucoma: Free radicals caused by light and environmental irritants can lead to glaucoma and other eye conditions.
  • Neurodegenerative diseases (such as Parkinson's and Alzheimer's disease): The brain is particularly vulnerable to oxidative stress because of its need for high oxygen levels. Research has found oxidative stress has a significant role in conditions that affect the brain, like Parkinson's disease and Alzheimer's disease.
  • Rheumatoid arthritis: Oxidative stress contributes to tissue damage around your joints in rheumatoid arthritis.

Antioxidants and Supplements

Antioxidants can protect your health by fighting oxidative stress. They can bind to free radicals and stop them from stealing electrons from other molecules in your body.

You can find antioxidants in various foods and spices. By including them in your diet, you can help reduce some of the effects of oxidative stress. Some common sources of antioxidants are:

  • Cocoa
  • Tea and coffee
  • Spices (such as cinnamon and turmeric)
  • Fruits and vegetables
  • Nuts (such as walnuts, almonds, and pecans)
  • Beans (including red, pinto, and kidney)
  • Olive oil
  • Fish

Other antioxidants include beta-carotene, coenzyme Q10, melatonin, vitamin C, and vitamin E.

If you're considering using a supplement, check with your doctor first. Some studies show that high doses of antioxidant supplements can be harmful, even increasing the risk of cancer in some cases. Your doctor can also tell you if a supplement will interact with a medication you're taking.

To ensure you get the antioxidants you need, focus on eating a variety of nutrient-rich foods. Avoid or limit foods that are highly processed or high in saturated fat or sugar.


Oxidative stress is linked to a number of conditions, including rheumatoid arthritis, diabetes, and cancer. A well-balanced diet can help provide antioxidants that help protect your body from oxidative stress.

Preventing Oxidative Stress

In addition to eating antioxidant-rich foods, there are other ways you can help limit the free radicals that cause oxidative stress. These include:

  • Quitting smoking: Research shows that oxidative stress from smoking decreases just a few weeks after quitting smoking.
  • Exercising regularly: While studies have found that exercise causes oxidative stress in the short term, that effect doesn't last long. It's thought that exercise can boost antioxidants in the body, helping to reduce overall oxidative stress.
  • Wearing sunscreen: Using a lotion with SPF 30 or higher, or avoiding the sun in its peak hours, can protect you from ultraviolet radiation that causes free radicals.
  • Getting enough sleep: When you don't get enough sleep at night, your antioxidant levels drop. Make sleep a priority to help your body to rest and recover.
  • Eating moderately: Researchers found that eating large amounts of food and eating continually throughout the day can generate more free radicals and oxidative stress. You can help reduce this by eating moderately with meals spaced out during the day.


Oxidative stress is caused when free radicals outnumber the antioxidants in your body. It can lead to cell damage and contribute to diseases like cancer and diabetes over time. One way to help minimize oxidative stress is to eat a healthy diet that provides antioxidants. You can also help boost your body's defenses by quitting smoking, exercising regularly, and getting enough sleep.

A Word From Verywell

Oxidative stress is a normal part of your body's functions, but over time, it can cause health issues. Talk with your doctor about ways that you help minimize oxidative stress through a healthy diet and other lifestyle changes.

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4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Devine JF. Chronic obstructive pulmonary disease: an overviewAm Health Drug Benefits. 2008;1(7):34–42.

  3. Weinreb RN, Aung T, Medeiros FA. The pathophysiology and treatment of glaucoma: a reviewJAMA. 2014;311(18):1901–1911. doi:10.1001/jama.2014.3192

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Additional Reading
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