Glossary

Free Radical

Written by Reviewed by the SYNC editorial team Published Last reviewed Editorial standards

Free Radical — an unstable molecule with an unpaired electron that reacts readily with other molecules, potentially damaging skin cells, DNA, and structural proteins in a chain reaction. In skin, free radicals are generated by ultraviolet light, pollution, and normal metabolism, and are a key driver of oxidative stress.

Key points

  • Free radicals seek to stabilize by taking electrons from nearby molecules, which can trigger cascading cellular damage.
  • External sources include ultraviolet radiation, air pollution, and smoke, while cells also produce them during normal energy metabolism.
  • In skin they can degrade collagen and elastin, contributing to visible signs of aging.
  • Antioxidants help neutralize free radicals by donating electrons without becoming unstable themselves.

Frequently asked

Are all free radicals harmful?

The body uses some free radicals for normal functions like immune defense, but an excess relative to antioxidants leads to oxidative stress and cell damage.

How can I protect skin from free radicals?

Daily broad-spectrum sunscreen, antioxidant-rich skincare, and limiting pollution and smoke exposure can help reduce free radical damage.

Related topics

This is a foundational entry in the SYNC Skin Encyclopedia and is expanded over time. Educational information only — not medical advice.

Encyclopedia

Further reading

This entry was written and checked against the sources below. They are published by clinical and scientific bodies, they are listed most readable first, and each one opens in a new tab. They are background for the whole entry rather than footnotes to individual sentences.

  1. An overview about oxidation in clinical practice of skin aging PubMed Central Peer-reviewed, open access pmc.ncbi.nlm.nih.gov
  2. Oxidative stress and antioxidant strategies in dermatology PubMed Central Peer-reviewed, open access pmc.ncbi.nlm.nih.gov
  3. What Are Reactive Oxygen Species, Free Radicals, and Oxidative Stress in Skin Diseases? PubMed Central Peer-reviewed, open access pmc.ncbi.nlm.nih.gov
  4. An overview about oxidation in clinical practice of skin aging PubMed Peer-reviewed (abstract) pubmed.ncbi.nlm.nih.gov
  5. Focus on the Contribution of Oxidative Stress in Skin Aging PubMed Peer-reviewed (abstract) pubmed.ncbi.nlm.nih.gov

SYNC does not publish medical advice. Nothing here replaces a consultation with a doctor or a pharmacist about your own skin.