What is Oxidative Stress and Should You Worry About It?

Updated: Mar. 17, 2022

We've all heard about antioxidants and free radicals—but the real concern is oxidative stress. Learn what triggers this dangerous condition and how to keep it from harming your health.

What is oxidative stress?

Whether you’re focused on your skin or your general health, you’ve no doubt heard the terms antioxidants and free radicals before. But the concept of oxidative stress may be less familiar.

“Oxidative stress is an imbalance between antioxidants and free radicals in the body,” explains Niket Sonpal, MD, an internist and faculty member at Touro College of Medicine on New York City. When free radicals outnumber antioxidants, your health is at risk.

“Free radicals are significant because they can cause a huge domino effect. They react so easily with other molecules. When this occurs, it is called oxidation. This can be harmful or beneficial to the body,” Dr. Sonpal says.

Good and bad? Oxidation and oxidative stress? Free radicals and antioxidants? If this sounds confusing, you’ve come to the right place: We’ve got answers.

(These are skin care products our editors love.)

Free radicals

So what exactly are these troublemakers? “Free radicals are oxygen-containing molecules that have an uneven number of electrons, making them very unstable and reactive,” explains Nancy Samolitis, MD, board-certified dermatologist and the co-founder and medical director of FACILE. “They can cause damage to cells that lead to signs of aging and disease.”

These molecules are unstable and highly reactive, explains Dr. Sonpal. “Despite having a life span of only a fraction of a second, they can damage DNA, sometimes severely enough to result in mutations that can lead to cancer.”

Free radicals are considered “two-faced,” explains California-based dermatologist Kelly Bickle, MD. Free radicals can cause cell death, so they’re considered an anti-cancer molecule and something that can potentially cause cancer.

What’s more, free radicals that work properly can ward off infection-causing pathogens, says Dr. Sonpal. Researchers have found the erratic molecules can be critical for wound healing.

The issue comes back to balance: “Free radicals are problematic because, when out of balance, they can possibly contribute to disease—including cancer, cardiovascular disease, and more, and may even contribute to the aging process,” says Dr. Bickle.

While science is still sorting out exactly how much trouble free radicals cause, she says, minimizing their actions can help keep you healthy.


If you’ve spent any time studying beauty product labels, you’ve run across the term “antioxidant” many times. The name says it all—they help prevent oxidation by taming free radicals.

Antioxidants include nutrients like vitamins C and E, and substances such as plant flavonoids; antioxidant molecules are able to donate an electron to free radicals, which puts the brakes on their destructive tendencies, explains Dr. Bickle. “They remove or neutralize free radicals.”

Dr. Sonpal explains that the body has built-in antioxidants to keep free radicals in balance; you can also boost your body’s antioxidants through the foods you eat.

Flora Waples, MD, medical director at Restor Medical Spa, explains that antioxidants are one of your body’s main tools to prevent free radical damage to DNA or cellular structures.

“Think of them like sunscreen for the inside of our bodies,” she says.

(Learn why you really need antioxidants.)

close up of woman looking at face in mirrorRUNSTUDIO/Getty Images

What is oxidation—and is it different than oxidative stress?

Oxidation and oxidative stress might seem like the same thing, but there are crucial differences.

“Oxidation is the process that leads to free radical formation,” says Dr. Waples. But oxidative stress refers to free radical formation that exceeds our protective mechanisms, she explains.

So while oxidation is a normal chemical process that forms free radicals—some of which can be helpful, remember—oxidative stress means the free radicals have overwhelmed the antioxidants and are attacking healthy tissues.

Think of oxidation as something that occurs all the time, naturally, says Dr. Sonpal. Oxidative stress is a condition you can help prevent through healthy food choices and lifestyle.

What areas of the body are at risk?

“Free radicals tend to be dispersed through the bloodstream to the entire body, so it’s more likely that oxidative damage will occur everywhere,” explains Reza Tirgari, MD, founder of Avalon Laser in San Diego.

One reason we associate oxidative stress with skin, says Dr. Tirgari, is because that’s where you’re most likely to notice it. Blackheads? Age spots? Wrinkles? Those are products of oxidative stress.

Oxidative damage can also have cumulative effects on skin structures like collagen and elastin, explains Dr. Tirgari. “This tends to lead to loose or sagging skin when the damage accumulates over time.”

But it’s not just skin, says Dr. Samolitis. “Oxidative stress can affect any tissue in the body causing inflammation and cellular malfunction.

This includes attacks on vital organs: Oxidative stress can increase the risk of heart disease, cancer, potentially arthritis, respiratory disease, and other inflammatory diseases as well, warns Dr. Bickle.

Oxidative stress may also contribute to neurodegenerative diseases such as Alzheimer’s and Parkinson’s, as well as hardening of the blood vessels (atherosclerosis), diabetes, and high blood pressure, says Dr. Sonpal.

In other words, there are plenty of compelling reasons to maintain your balance of free radicals and antioxidants.

(These are everyday habits that reduce your risk of Alzheimer’s and dementia.)

Antioxidant-rich foods

The foods you eat can tame oxidative stress internally, says Dr. Samolitis.

“There are studies that suggest certain foods can reduce oxidative damage and inflammation,” says Dr. Tirgari. “It will come as little surprise that diets high in fruits and vegetables are very protective, while diets high in meat and dairy tend to be much worse.”

Dr. Bickle recommends antioxidant-rich foods high in vitamin C, vitamin E, and beta carotene. Some examples:

A good rule of thumb is to add more plant-based foods to your diet—and don’t forget herbs, and spices, says Dr. Bickle.

Lifestyle factors that worsen oxidative stress

Behaviors like smoking cigarettes and UV light damage from tanning boost oxidative stress. “Both create chemicals that can cause free radical formation in the body and damage to organs,” says Dr. Tirgari. A sedentary lifestyle also seems to increase oxidative stress.

Dr. Samolitis also cites exposure to toxic chemicals and air pollution as other contributing factors.

While healthy diets can help, low-quality diets can hurt—especially ones high in red meat. Although studies have shown that red wine can help decrease oxidative stress and boost antioxidants in the body, too much alcohol, as well as highly processed or sugary foods, is detrimental.

“It is thought that diet, lifestyle, and environment can all contribute,” says Dr. Bickle. “Obesity, consuming processed foods and sugar, smoking tobacco, drinking alcohol, and exposure to pollution and chemicals/pesticides can contribute to oxidative stress in our bodies.”

(This is what happens when you stop eating processed foods.)

Preventing oxidative stress

At the end of the day, a healthy lifestyle is key in helping to prevent oxidative stress.

“Avoiding environmental triggers of oxidative stress is the most effective way to protect your body,” says Dr. Samolitis. “Behaviors including UV protection with sunscreen, sun protective clothing and sun avoidance, not smoking, avoiding processed foods and increasing intake of organic foods can reduce your exposure to damaging free radicals and keep your body healthy.”

For Dr. Tirgari, both exercise and hydration are important.

“Moderate exercise, done at least three to four times a week, can greatly improve the body’s ability to repair oxidative damage. Maintaining hydration—i.e. drinking plenty of fluids—limiting caffeine and especially alcohol consumption and maintaining good sleep habits can also help.”

At the end of the day, all the behaviors you should be following are intuitive, rather than rocket science.

“Eating a plant-based diet rich in antioxidants, getting appropriate sleep, avoiding alcohol and tobacco products, wearing sunscreen. Basically: doing all the things that your mother told you to do,” says Dr. Waples.