Oxidative stress occurs when some molecules (oxidizing agents) take electrons from other molecules or atoms. The substances that can exist with missing electrons are called free radicals. Most of these free radicals are oxygen molecules or atoms.

Free radicals are highly reactive, always ready to give away the odd electron, or to accept one. After they find a pair for the lonesome electron, they lose their activity, but the atom that has just lost an electron becomes a free radical in turn. It is a necessary part of metabolic process. However, too many free radicals cause a dangerous chain reaction that destroys cellular compounds and can damage DNA, proteins and lipids (fats).

Cellular damage can result in diseases, such as cancer, inhibit enzyme activity and produce mutations in genetic material that makes aging go faster.

How exactly can oxidative stress speed skin aging?

Wrinkles occur when skin loses its elasticity. The loss of elasticity is caused by extensive formation and accumulation of collagen cross-links. Collagen cross-linking is a result of a chemical process that starts with nonenzymatic attachment of glucose to a collagen molecule.

When enzymes attach glucose to collagen, there is a reason for it and a purpose. Nonezymatic attachment, on the other hand, is random. Collagen cross linking in this case is uncontrollable and more often than not - unnecessary. Once cross-linking occurs, it is irreversible.

By inhibiting enzyme production, free radicals lead to chaotic collagen cross linking.