Oxidative Stress: Free Radicals and Antioxidant Defense

Free radicals and oxidative stress

Oxygen metabolism produces reactive oxygen species (ROS) as a byproduct. These molecules have an unpaired electron and steal electrons from neighboring molecules for "balance" — this stealing process initiates a chain reaction. If they attack lipids, cell membranes are damaged. If they attack proteins, collagen damage begins. If they attack DNA, the risk of mutation increases.

Our bodies have both enzymatic (superoxide dismutase, catalase, glutathione peroxidase) and non-enzymatic (vitamin C, vitamin E, uric acid) antioxidant systems. When young, this system is robust — free radicals are produced, neutralized. With age, antioxidant capacity decreases, radical load increases; oxidative stress accumulates.

Vitamin C: the gold standard

Topical L-ascorbic acid (10-20%) is the first-line antioxidant in skin aging. Its function is threefold: (1) free radical neutralization, (2) enzyme cofactor in collagen synthesis, (3) anti-spot effect via tyrosinase inhibition. Studies show that topical vitamin C measurably increases the skin's antioxidant pool within hours.

Vitamin C elements are unstable — it degrades with oxygen, light, and heat. A quality product is formulated in a dark glass bottle, at low pH (below 3.5), often with vitamin E and ferulic acid. Ferulic acid stabilizes vitamin C and can increase its effect up to 8 times.

Other antioxidant heroes

Vitamin E (alpha-tocopherol): an antioxidant of the lipid membrane. It has high synergy with vitamin C — the C+E combination is more effective than each alone.

Resveratrol: a polyphenol found in grapes; activates sirtuin genes, slows cell aging through a mechanism said to "mimic caloric restriction."

Niacinamide (vitamin B3): strengthens the barrier, reduces pigmentation, balances sebum. Proven at 5% concentration twice daily.

Ferulic acid: a plant-derived antioxidant; stabilizes vitamins C and E, and its own antioxidant effect is also significant.

Glutathione: the cell's "master antioxidant"; but has limited effectiveness in topical use due to poor penetration. Systemic form is used intravenously in some longevity clinics.