What is a free radical?

May 17, 2016

What is a free radical?

A free radical is a very unstable molecule that has an unpaired electron. As you may remember from chemistry classes, electrons want to exist in pairs. A molecule with an unpaired electron will try to steal an electron from somewhere else, meaning that the molecule is very reactive.

A free radical has an unpaired electron and wants to satisfy it by taking an electron from a molecule nearby. They are short lived, unstable, and react with other molecules to achieve stability. The scientific term for free radical is Reactive Oxygen Species (ROS).

There is a variety of free radicals that are produced inside your cells. Some of them are useful in low concentrations, but others are extremely dangerous. There are some free radicals that are so harmful and reactive that they will steal an electron from ANYTHING, including DNA, proteins, lipids, and cell structures. One way to understand the nature of free radicals is to think about it as fire. A controlled flame can be used for cooking and is very useful. However, uncontrolled fire like a wildfire can cause massive, irreversible damage. Same thing can be said about free radicals.


The most common free radical is the Superoxide Anion (O2-).  The Superoxide Anion is the most common because it gets produced by your Mitochondria (engines of your cells) as a byproduct of metabolism every second of your life. (You can learn more about how your mitochondria produces energy and free radicals on this blog post.) Superoxide Anion is constantly being produced and although they are not so dangerous by themselves, they react with other free radicals to create highly reactive free radicals. So it’s important to eliminate them before they get out of hand.

Your cells have a way to neutralize Superoxide Anion via a two-step process involving two antioxidant enzymes. The first step is the conversion of Superoxide Anion to  Hydrogen Peroxide by Superoxide Dismutase.

Hydrogen Peroxide is a Free Radical that is used by your immune cells!
Once Superoxide Anion is converted to Hydrogen Peroxide, your white blood cells (immune cells) use hydrogen peroxide as a corrosive chemical to break down and kill bacteria. Pretty useful right? But too much hydrogen peroxide floating around can be dangerous because they can start damaging your own cells! That’s why there’s two enzymes,Catalase and Glutathione Peroxidase that transform Hydrogen Peroxide into water.

As you can see, antioxidants exist inside your cells to take care of free radicals effectively. Also, some free radicals like Hydrogen Peroxide are useful at low concentrations. Nitric Oxide (•NO) is an example of another useful free radical. Nitric Oxide is a signaling molecule that helps relax your blood vessels when you need more blood to a certain area of your body.

The Most Dangerous Free Radicals
The most dangerous free radicals are the Hydroxyl Radicals(•OH) and Peroxynitrite (ONOO•). These two free radicals are dangerous because they are HIGHLY reactive. If they come into contact with any molecule, they can steal an electron from it. Especially vulnerable to hydroxyl radicals and peroxynitrite are DNA, proteins, and lipids that contain many electrons.

How  are hydroxyl radicals formed? Hydroxyl radicals form when there are too much Superoxide Anion and Hydrogen Peroxide floating around in the cells. These two free radicals combine to form deadly hydroxyl radicals. 

Peroxynitrite is formed when superoxide combines with nitric oxide. As you can see, the superoxide anion on it’s own is not a dangerous free radical, but a buildup of superoxide anion molecules can lead to the formation of dangerous free radicals like hydroxyl radicals and peroxynitrites.



Free radicals are going to be a part of your life no matter what. That’s why it’s important to find ways to minimize free radical damage. Free radical damage can result in all kinds of health issues, some of which will be discussed in future blogs. The best way to protect yourself is to figure out ways to improve your antioxidant levels and minimize things that cause more free radicals to be produced inside your cells.

Lifestyle, Diet, and Environment
The main things that dictate your free radical levels are your lifestyle, diet and environment. Some are easier to control than others, but avoiding and eliminating the following things from your life is the best way to minimize free radical damage. The main things are – StressAlcohol & DrugsJunk Food, and Pollution.

Stress – You experience stress in your life constantly. Stress about your job, your future, or about what to do next. Stress causes your body to work in over-drive because your body thinks that it’s being threatened. This stress response causes stress hormones such as cortisol and adrenaline to flood your body, ramping up your metabolism, your oxygen consumption, and consequently your free radical production. Take a moment to relax. Try meditation or some other stress relieving activities to insure that you get a well-deserved break from stress (and excess free radicals).

Alcohol & Drugs – Alcohol and Drugs, including prescription drugs, are essentially toxins. When you continuously use alcohol and drugs, your cells have to work hard to remove the toxins from your cells. This causes your cells to become overloaded and inefficient. When your cells are not working as well as they should be, more free radicals are produced. Alcohol and drugs have been directly linked to increased free radical production. As you already know, moderation is key!

Junk Food – Junk food is engineered to taste delicious. Science has shown what types of flavors and textures stimulate our hunger and junk food is the culmination of all the research and testing into this field. While junk food may taste good, it’s essentially junk, meaning there’s not a significant source of nutrients in them, AND they’re chock full of preservatives and other synthetic chemicals. You are what you eat, so when you eat dead food like Junk Food, your cells won’t be lively and energetic like they can be. Avoid Junk food as much as possible and try to eat healthier, organic, REAL food! REAL food means non-processed food. It’s food that won’t have a Nutrition Facts on the packaging. Real food will help your cells become more efficient because they contain the building blocks the cells need to function effectively and they won’t be sludged up with chemicals and toxins.

Pollution – Clean Air and clean water is so important. You are constantly exposed to chemicals in your everyday life. Minimize your exposure to harmful chemicals in laundry detergent, soap, shampoo, carbon monoxide from cars, gas, etc. When these chemicals build-up in your system your cells becoming inefficient and in turn produce more free radicals. Use non-toxic alternatives for shampoo, soap, and detergent. The water that you drink needs to be pure and filtered. Talk to a filtration specialist to really get the scoop on what’s in your water. Air filters for your home and work will also help tremendously.

One Thing that DIRECTLY Produces Hydroxyl Radicals
Radiation such as X-Rays, Electromagnetic Radiation, or Nuclear Radiation directly produce Hydroxyl Radicals in your cells. That’s because radiation is so energetic that it can split water into a Hydroxyl Radical, as shown in the figure below. That’s why it’s important to avoid radiation as much as possible. However, it may be difficult to eliminate completely because of the radiation pollution in our environment due to the Fukushima Disaster and other radiation events.


Free radicals are unstable molecules that want to steal electrons from other molecules inside your cells, damaging them in the process. There are some useful free radicals, but when there’s too many free radicals they cause irreversible damage to your cells, which can lead to health complications over time. The best way to minimize free radicals is to avoid things that contribute to inefficient energy production in your cells. The other good way is to get some quality sleep and supplement your diet with antioxidants.

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