Free radicals
Also called: Reactive oxygen species, ROS
Free radicals are unstable molecules that can damage skin lipids, proteins, and DNA when oxidative stress overwhelms the skin's normal defences. Antioxidants and sunscreen help reduce that stress.
At a glance
- UV exposure is a major everyday source of oxidative stress in skin.
- Antioxidants support sunscreen; they do not replace it.
- Vitamin C, vitamin E, ferulic acid, and green tea are common antioxidant ingredients.
On this page
The short answer
Free radicals are unstable molecules. In skin, too much oxidative stress can damage lipids, proteins, and DNA, which is why sunscreen and antioxidants come up so often in pigmentation and ageing conversations.
The useful skincare translation is simple: protect in the morning, repair gently at night, and do not expect one antioxidant serum to act like a tiny security guard with a clipboard.
Why free radicals matter
UV exposure is one major source of oxidative stress in skin. A vitamin C review[1] explains that vitamin C contributes to antioxidant protection and collagen biology in skin, while also noting how exposure and deficiency can affect skin health.
Topical antioxidants can add support. A 2003 study[2] found that combined topical vitamin C and vitamin E improved UV photoprotection compared with either antioxidant alone. That does not mean antioxidants replace broad-spectrum sunscreen. It means they can sit beside it.
What to do with this term
If a product says "fights free radicals," read it as antioxidant support, not magic repair.
Useful antioxidant ingredients include l-ascorbic acid, tocopherol, ferulic acid, and green tea extract. The calm routine is still the same: cleanse gently, use a moisturiser your skin tolerates, apply SPF every morning, and avoid turning antioxidant shopping into a second job.
Keep reading
Dictionary
Broad spectrum
Dictionary
UVA
Dictionary
UVB
Ingredient
Vitamin C (L-ascorbic acid)
Ingredient
Vitamin E (Tocopherol)
Ingredient
Ferulic acid
Ingredient
Camellia Sinensis Leaf Extract
Condition
Pigmentation
Condition
Signs of ageing
Condition
Sensitive skin
Guide
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Guide
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Common questions
Do antioxidants stop free radicals?
They help neutralise some oxidative stress, but no topical antioxidant blocks every free radical. Sunscreen and sensible sun behaviour still matter.
Are free radicals always bad?
No. The body uses reactive molecules in normal biology. Skin problems arise when oxidative stress exceeds what the skin can comfortably handle.