The Free Radical Theory of Aging

Do you know what free radicals are? You may have heard that they can damage your skin and have an aging effect on your body. But is that true? Here's what you should know about the free radical theory of aging and what the most recent research has to say about its legitimacy.

Older adult looking out of a large window while holding a mug
Aging in your own home. Jasper Cole / Blend Images / Getty Images

What Are Free Radicals?

Free radicals are a byproduct of normal cell function. When cells create energy, they also produce unstable oxygen molecules. These molecules, called free radicals, have a free electron, which makes the molecule highly unstable. Free radicals bond to other molecules in the body, causing proteins and other essential molecules to not function as they should.

Free radicals can be formed through this natural process, but they can also be caused by diet, stress, smoking, alcohol, exercise, inflammation drugs, exposure to the sun or air pollutants. 

What Are Antioxidants?

Antioxidants are substances found in plants that soak up free radicals like sponges and are believed to minimize free radical damage If your body has plenty of antioxidants available, it can minimize the damage caused by free radicals. There is some evidence that we can only get the full antioxidant benefits from eating real plants and other foods. Supplements appear not to be as effective.

Free Radicals and Aging

The free radical theory of aging asserts that many of the changes that occur as our bodies age are caused by free radicals. Damage to DNA, protein cross-linking and other changes have been attributed to free radicals. Over time, this damage accumulates and causes us to experience aging.

There is some evidence to support this claim. Studies have shown that increasing the number of antioxidants in the diets of mice and other animals can slow the effects of aging. This theory does not fully explain all the changes that occur during aging and it is likely that free radicals are only one part of the aging equation.

In fact, more recent research suggests that free radicals may actually be beneficial to the body in some cases and that consuming more antioxidants than you would through food have the opposite intended effect. In one study (in worms) those that were made more free radicals or were treated with free radicals lived longer than other worms. It's not clear if these findings would carry over into humans, but research is beginning to question the conventions of the free radical theory of aging. 

The Takeaway

Regardless of the findings, it is a good idea to eat a healthy diet, not smoke, limit alcohol intake, get plenty of exercises and avoid air pollution and direct exposure to the sun. Taking these measures is good for your health in general, but can also slow down the production of free radicals.

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.
  • Discovery Channel. (2013, February 11). Do Free Radicals Really Cause Aging?

  • Howard, D. (n.d.). What Is A Free Radical? From The International Dermal Institute.

By Mark Stibich, PhD
Mark Stibich, PhD, FIDSA, is a behavior change expert with experience helping individuals make lasting lifestyle improvements.