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Glossary 

# Antioxidant

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## Definition

Antioxidants are molecules that protect the skin from damage caused by free radicals — unstable atoms generated by UV radiation, pollution, and other environmental stressors. Free radicals attack healthy skin cells, accelerating aging and causing hyperpigmentation. Common antioxidants used in skincare include vitamin C (ascorbic acid), vitamin E (tocopherol), niacinamide, resveratrol, and green tea extract. These ingredients neutralize free radicals before they can damage DNA, collagen, and elastin. Antioxidants are most effective when applied topically in serums, particularly in the morning before sunscreen, to provide an additional layer of defense against environmental damage. Many antioxidants also offer brightening, anti-inflammatory, or hydrating benefits beyond their protective role.

## Related Terms

[Free Radicals](/glossary/free-radicals)[Vitamin C (Ascorbic Acid)](/glossary/vitamin-c-ascorbic-acid)[Vitamin E (Tocopherol)](/glossary/vitamin-e-tocopherol)[Oxidative Stress](/glossary/oxidative-stress)

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