Overview

Antioxidants are substances that seem to reduce oxidative stress. Oxidative stress is thought to lead to aging and certain diseases such as cancer and diabetes.

Common supplement ingredients thought to have antioxidant effects include vitamin E, beta-carotene, vitamin C, selenium, and others.

People use antioxidants for various cancers, heart disease, asthma, cystic fibrosis, and many other conditions, but there is no good evidence to support these uses.

Uses & Effectiveness

Possibly Ineffective for

  • Bladder cancer. Taking antioxidant supplements by mouth doesn't seem to reduce the risk of bladder cancer.
  • Cancer. Taking antioxidant supplements by mouth doesn't seem to prevent cancer or reduce the risk of death from cancer.
  • Cataracts. Taking antioxidant supplements by mouth doesn't seem reduce the risk of cataracts or of needing cataract surgery.
  • Colon cancer, rectal cancer. Taking antioxidants doesn't seem to reduce the risk of colon or rectal cancer.
  • Heart disease. Taking antioxidant supplements by mouth doesn't seem to reduce the risk of heart attack, stroke, or death in people with heart disease.
  • Nonmelanoma skin cancer. Taking antioxidants supplements by mouth doesn't seem to reduce the risk of nonmelanoma skin cancer.
  • Prostate cancer. Taking antioxidant supplements by mouth doesn't seem to reduce the risk of prostate cancer.

There is interest in using antioxidants for a number of other purposes, but there isn't enough reliable information to say whether it might be helpful.

Side Effects

When taken by mouth: Antioxidants are likely safe when used appropriately. But certain antioxidants are possibly unsafe when used in large doses. Antioxidants like beta-carotene and vitamin E can cause serious side effects when used in large doses. See specific ingredients for more detailed safety information.

Special Precautions and Warnings

When taken by mouth: Antioxidants are likely safe when used appropriately. But certain antioxidants are possibly unsafe when used in large doses. Antioxidants like beta-carotene and vitamin E can cause serious side effects when used in large doses. See specific ingredients for more detailed safety information.

Pregnancy: Antioxidants are possibly safe when taken by mouth in appropriate doses during pregnancy. See specific ingredients for more detailed safety information.

Breast-feeding: There isn't enough reliable information to know if antioxidants in general are safe to use when breast-feeding. See specific ingredients for detailed safety information.

Interactions

We currently have no information for Antioxidants overview.

Dosing

Antioxidant products are typically taken by mouth. Common supplement ingredients thought to have antioxidant effects include vitamin E, beta-carotene, vitamin C, selenium, and others. Speak with a healthcare provider to find out which specific antioxidants and what dose might be best for a specific condition.
View References
Show More Show Less

CONDITIONS OF USE AND IMPORTANT INFORMATION: This information is meant to supplement, not replace advice from your doctor or healthcare provider and is not meant to cover all possible uses, precautions, interactions or adverse effects. This information may not fit your specific health circumstances. Never delay or disregard seeking professional medical advice from your doctor or other qualified health care provider because of something you have read on WebMD. You should always speak with your doctor or health care professional before you start, stop, or change any prescribed part of your health care plan or treatment and to determine what course of therapy is right for you.

This copyrighted material is licensed from Therapeutic Research Center, LLC. Information from this source is evidence-based and objective, and without commercial influence. For professional medical information on natural medicines, see Natural Medicines Comprehensive Database Professional Version.
Licensed from Therapeutic Research Center, LLC
Copyright © 1995-2025 by Therapeutic Research Center, LLC. All Rights Reserved.