Quick answer

Free radicals are reactive molecules your body makes just by being alive; antioxidants neutralise the excess before it can damage cells. Neither is simply “good” or “bad” — health depends on the balance between them.

Free radicals do essential jobs like fighting infection and cell signaling, while antioxidants such as glutathione keep them from causing unnecessary wear and tear.

Your body is constantly performing a balancing act.

Every time you breathe, exercise, digest a meal, or even think, your cells produce energy to keep you alive. But energy production comes with a natural by-product: highly reactive molecules known as free radicals.

Despite their negative reputation, free radicals aren’t inherently harmful. In fact, your body depends on them for important functions, including fighting infections and helping cells communicate.

Problems arise only when free radicals begin to outnumber your body’s defenses.

That’s where antioxidants come in. Antioxidants help neutralize excess free radicals before they can damage healthy cells. Together, free radicals and antioxidants form a delicate balance that supports normal cellular function.

Understanding this balance helps explain why glutathione — often called the body’s “master antioxidant” — is so important.

What Are Free Radicals?

Free radicals are unstable molecules with one or more unpaired electrons.

Because they are missing an electron, they constantly seek to steal one from nearby molecules. This makes them highly reactive.

unpairedelectron
Figure 1 · A free radical has an unpaired electron — which drives it to “grab” one from a neighbouring molecule.

When a free radical removes an electron from another molecule, it can create a chain reaction that spreads from cell to cell.

If this process isn’t controlled, it can damage:

  • Cell membranes
  • Proteins
  • DNA
  • Mitochondria (the structures that produce energy inside cells)

Fortunately, your body has built-in defense systems to help prevent this damage.

Where Do Free Radicals Come From?

Free radicals are produced naturally every day.

Common sources include:

  • Normal energy production in mitochondria
  • Exercise
  • Immune system activity
  • Sunlight (UV radiation)
  • Air pollution
  • Cigarette smoke
  • Alcohol
  • Certain medications
  • Chronic inflammation
  • Psychological stress

Some free radicals are even produced intentionally by your immune system to help destroy harmful bacteria and viruses.

In other words, free radicals are a normal and necessary part of life.

What Are Antioxidants?

Antioxidants are molecules that safely donate an electron to a free radical without becoming unstable themselves.

antioxidant electron neutralised
Figure 2 · An antioxidant donates an electron to a free radical — neutralising it while staying stable itself.

By doing this, they stop harmful chain reactions before widespread cellular damage occurs.

Think of antioxidants as your body’s cleanup crew. They help keep normal biological processes from causing unnecessary wear and tear on your cells.

Types of Antioxidants

Your body relies on two main sources of antioxidants.

Antioxidants you eat. Many fruits, vegetables, nuts, and other plant foods contain antioxidants, including:

  • Vitamin C
  • Vitamin E
  • Beta-carotene
  • Polyphenols
  • Flavonoids

Eating a variety of colorful plant foods helps provide a broad range of these protective compounds.

Antioxidants your body makes. Your body also produces its own antioxidant defenses, including:

  • Glutathione
  • Superoxide dismutase (SOD)
  • Catalase

Among these, glutathione is especially important because it works inside nearly every cell and helps regenerate other antioxidants after they have been used.

Why Balance Matters More Than Elimination

A common misconception is that all free radicals are harmful and should be eliminated.

That’s not how human biology works.

Free radicals play several beneficial roles, including:

  • Helping immune cells destroy pathogens
  • Supporting normal cell signaling
  • Assisting with tissue repair
  • Triggering healthy adaptations to exercise

Likewise, too many antioxidants are not always better.

Important context

Large clinical studies have shown that high-dose antioxidant supplements do not consistently improve health outcomes in healthy people and, in some cases, may even interfere with beneficial cellular processes.

The goal isn’t to eliminate free radicals — it’s to maintain a healthy balance between free radicals and antioxidants.

What Happens When the Balance Is Lost?

When free radicals accumulate faster than antioxidants can neutralize them, oxidative stress develops.

Over time, excessive oxidative stress may contribute to:

  • Damage to DNA
  • Oxidation of fats and proteins
  • Reduced mitochondrial function
  • Chronic inflammation
  • Accelerated cellular aging

Researchers have observed increased oxidative stress in many chronic diseases. However, oxidative stress is generally considered one contributing factor among many rather than a single cause.

Where Does Glutathione Fit In?

Glutathione is one of your body’s most important antioxidant systems.

Unlike many antioxidants that come from food, glutathione is produced naturally inside your cells.

chain stopped
Figure 3 · A single antioxidant can halt a chain reaction — stopping one radical from creating the next.

It helps by:

  • Neutralizing free radicals
  • Recycling vitamins C and E
  • Supporting normal liver detoxification processes
  • Protecting mitochondria
  • Maintaining healthy immune function
  • Helping repair oxidative damage

Because nearly every cell depends on glutathione, researchers often describe it as a central component of the body’s antioxidant network.

Can You Support Your Natural Antioxidant Defenses?

Yes. While you can’t — and shouldn’t — eliminate free radicals completely, you can support your body’s ability to keep them in balance.

Healthy habits include:

  • Eating a diet rich in fruits and vegetables
  • Getting enough protein to support glutathione production
  • Exercising regularly
  • Sleeping well
  • Managing stress
  • Avoiding smoking
  • Limiting excessive alcohol consumption
  • Maintaining a healthy body weight

These lifestyle choices help your body’s natural antioxidant systems function effectively.

What the Research Shows

Decades of research have established that both free radicals and antioxidants are essential to normal human biology.

Free radicals are necessary for immune defense and cell signaling, while antioxidants protect cells from excessive oxidative damage.

Current evidence suggests that maintaining this balance is more important than trying to eliminate free radicals altogether. Researchers continue to study how antioxidant systems — particularly glutathione — may support healthy aging and cellular function.

What Researchers Still Don’t Know

Although scientists understand the basic biology of free radicals and antioxidants, important questions remain.

Researchers continue to investigate:

  • Why oxidative stress affects some people more than others
  • How genetics influence antioxidant defenses
  • Which dietary patterns best support long-term antioxidant balance
  • Which populations may benefit from targeted antioxidant interventions
  • The most reliable ways to measure oxidative stress in clinical settings

As new research emerges, our understanding of these processes continues to evolve.

Key takeaways

  • Free radicals are unstable molecules produced naturally by your body.
  • They play important roles in immune defense and normal cell signaling.
  • Antioxidants help neutralize excess free radicals before they damage cells.
  • Balance — not elimination — is the key to healthy cellular function.
  • Glutathione is one of the body’s most important antioxidants because it works inside nearly every cell.

Frequently asked questions

Are free radicals always harmful?
No. Free radicals are a normal part of human biology and are essential for immune function and cell communication. Problems occur only when they become excessive.
What is the difference between free radicals and antioxidants?
Free radicals are reactive molecules that can damage cells when present in excess. Antioxidants help neutralize them and protect healthy tissues.
Can eating antioxidant-rich foods eliminate oxidative stress?
No. A healthy diet supports your body’s antioxidant defenses, but oxidative stress is a normal part of life and cannot be completely eliminated.
Why is glutathione called the “master antioxidant”?
Glutathione works inside nearly every cell, helps neutralize free radicals, regenerates other antioxidants, and supports several essential cellular processes, making it one of the body’s most important antioxidant systems.

References

  1. Halliwell B, Gutteridge JMC. Free Radicals in Biology and Medicine. Textbook
  2. Sies H. Oxidative Stress: A Concept in Redox Biology and Medicine. Redox Biology. Review
  3. Forman HJ, Zhang H, Rinna A. Glutathione: Overview of Its Protective Roles. Molecular Aspects of Medicine. Review
  4. Lu SC. Regulation of Glutathione Synthesis. Molecular Aspects of Medicine. Review
  5. Valko M, Rhodes CJ, Moncol J, et al. Free Radicals, Metals and Antioxidants in Oxidative Stress-Induced Cancer. Chemico-Biological Interactions. Review