What Are Antioxidants?
- , by SANUSq Research team
- 9 min reading time
You've heard the word everywhere — "antioxidants" splashed across foods, drinks and supplements. But what are they really, and why does your body need them? The answer starts with oxidative stress.
The battle inside your cells
Antioxidants are compounds that protect your cells and tissues from the damage caused by free radicals. To understand why that matters, picture what's happening inside you every moment: as your cells turn food into energy, they generate reactive molecules called free radicals as a natural by-product. In small amounts these are harmless — even useful — but they're also produced in excess by things like pollution, UV light, smoking, stress and a poor diet. When free radicals outnumber your body's defences, the result is a state called oxidative stress, and it's this imbalance that antioxidants are there to counter. Far from being mere marketing buzzwords, antioxidants are a genuinely important part of how your body protects itself — and understanding them helps you support your health in real, practical ways.
What is oxidative stress?
Oxidative stress is the imbalance between damaging free radicals and the antioxidants that neutralise them. When free radicals accumulate unchecked, they start to damage the crucial building blocks of your cells.
Reviews of free radicals and antioxidant defences explain that overproduction of free radicals leads to oxidative stress, which damages DNA, proteins and lipids and contributes to the development of chronic conditions such as cardiovascular disease, neurodegenerative disorders, cancer and inflammatory diseases (Chandimali et al., 2025).
How antioxidants defend you
Antioxidants work by neutralising free radicals — essentially donating a spare electron to stabilise these reactive molecules before they can harm your cells. Your body has a two-part defence: antioxidants it makes itself, and antioxidants it gets from food.
The body maintains its own antioxidant defence system — including enzymes such as superoxide dismutase, catalase and glutathione peroxidase — and supplements this with dietary, non-enzymatic antioxidants such as vitamin C, vitamin E, glutathione and plant polyphenols that help keep free radicals in check (dietary antioxidants review).
Some antioxidants are familiar names — vitamin C, vitamin E, beta-carotene, selenium — while others include the vast family of plant compounds called polyphenols and flavonoids, found in colourful fruit and vegetables, tea, herbs and spices. Glutathione, made within your own cells, is often called the "master antioxidant" for its central role. Together they form a network that protects you from the oxidative damage linked to ageing and many chronic diseases.
An important thing to appreciate is that antioxidants don't work in isolation — they operate as a co-operative team, which is part of why variety matters so much. Different antioxidants tackle different types of free radicals in different parts of the cell: some are water-soluble and work in the watery interior of cells and the bloodstream (like vitamin C), while others are fat-soluble and protect cell membranes (like vitamin E). Elegantly, they also help regenerate one another — for instance, vitamin C can help restore vitamin E to its active form after it has neutralised a free radical, and glutathione in turn helps recycle vitamin C. This interdependence means that no single antioxidant, however celebrated, can do the whole job alone; they rely on each other, working as a coordinated defence network. It's a key reason why nutrition scientists consistently favour getting a broad range of antioxidants from a varied diet over relying heavily on one isolated compound in a high dose. A diverse intake keeps the whole team well stocked and working in concert — which is how your body's antioxidant defences are designed to function.
Getting antioxidants the smart way
Here's where an honest, evidence-based perspective really helps. It's tempting to think that if antioxidants are good, high-dose antioxidant supplements must be better — but the science urges caution. Large trials of high-dose antioxidant supplements have often failed to show the hoped-for benefits, and in some cases very high doses can even act as pro-oxidants, disrupting the body's natural balance. The reliable, well-evidenced approach is to get your antioxidants primarily from a varied, colourful, whole-food diet: a rainbow of vegetables and fruit, berries, nuts, seeds, wholegrains, herbs, spices, green tea and a little dark chocolate all deliver a rich orchestra of antioxidants working together, alongside fibre and other nutrients. Think "eat the rainbow" rather than "megadose a pill".
There's a fascinating reason why whole foods outperform isolated antioxidant pills, and it's worth understanding. When you eat a berry or a piece of broccoli, you're not just getting one antioxidant — you're getting dozens of different protective compounds, plus fibre, vitamins and minerals, all packaged together in the amounts and combinations nature intended. These compounds appear to work synergistically, supporting and enhancing one another in ways a single high-dose supplement simply can't replicate. There's also a matter of balance: your body actually uses small amounts of free radicals for important jobs, such as fighting infection and signalling between cells, so flooding the system with massive doses of an isolated antioxidant can disrupt these normal, useful processes. This helps make sense of the otherwise puzzling trial results, where megadoses of single antioxidants have sometimes been unhelpful or even harmful, while diets naturally rich in antioxidant foods are consistently linked to better health. The lesson isn't that antioxidants don't matter — they clearly do — but that the wisest way to harness them is through the food they come in, letting your body take what it needs from a rich and varied supply.
Where a supplement genuinely helps is in supporting specific nutrients that may be lacking — and our Liposomal Vitamin C with Glutathione pairs two key antioxidants in a well-absorbed form. Supporting your body's defences also means reducing the free-radical load: don't smoke, protect your skin from excess sun, moderate alcohol and manage stress, as we explore in the best anti-inflammatory foods.
Frequently asked questions
What are antioxidants?
Antioxidants are compounds that protect your cells from damage by neutralising free radicals — reactive molecules produced during normal metabolism and by factors like pollution and smoking. They include vitamins C and E, beta-carotene, selenium, plant polyphenols, and glutathione, the body's "master antioxidant".
What is oxidative stress?
Oxidative stress is the imbalance between damaging free radicals and the antioxidants that neutralise them. When free radicals accumulate unchecked, they damage DNA, proteins and lipids — a process linked to ageing and chronic conditions including cardiovascular disease, neurodegenerative disorders and cancer.
What foods are high in antioxidants?
Colourful fruit and vegetables (berries, leafy greens, peppers, tomatoes), nuts, seeds, wholegrains, herbs and spices, green tea, and a little dark chocolate are all rich sources. Eating a varied "rainbow" of these delivers a broad range of antioxidants working together — the most reliable approach.
Should I take antioxidant supplements?
For most people, getting antioxidants from a varied whole-food diet is best. Large trials of high-dose antioxidant supplements have often failed to show benefit, and very high doses can even act as pro-oxidants. Supplements help most when supporting a specific nutrient that may be lacking, rather than as megadoses.
Can you take too many antioxidants?
Yes — more isn't always better. Very high doses of isolated antioxidant supplements can disrupt the body's natural redox balance and, in some cases, act as pro-oxidants, potentially doing harm. This is why a food-first approach and sensible supplementation are wiser than megadosing.
What is the "master antioxidant"?
Glutathione is often called the master antioxidant. Made within your own cells, it plays a central role in neutralising free radicals, supports detoxification and immunity, and helps regenerate other antioxidants like vitamins C and E — sitting at the hub of your body's antioxidant defences.
Support your antioxidant defences
Our Liposomal Vitamin C with Glutathione pairs two key antioxidants in a well-absorbed form to complement an antioxidant-rich diet.
References
- Chandimali N, Bak SG, Park EH, et al. Free radicals and their impact on health and antioxidant defenses: a review. Cell Death Discovery. 2025;11(1):19. PMID 39856066
- Chaudhary P, Janmeda P, Docea AO, et al. Oxidative stress, free radicals and antioxidants: potential crosstalk in the pathophysiology of human diseases. Frontiers in Chemistry. 2023;11:1158198. doi:10.3389/fchem.2023.1158198/full
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The team at SANUSq.
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The health information in this article is provided for educational purposes only. Consult your healthcare professional before making any medical decisions.
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