Free radicals are atoms or molecules with unpaired electrons. The production of free radicals in our cells occurs by normal respiration and the assimilation of sugar. Free radicals are an unavoidable occurrence in biochemical reactions. Free radicals are the natural product of any chemical reaction and they fit into the bodies overall balance. White blood cells use free radicals in hydrogen peroxide to destroy invading bacteria and viruses.
Atoms normally contain an even number of paired electrons.
If for some reason an electron becomes separated, it causes an imbalance and becomes a free radical. The unbalanced free radical can damage cells that do not have sufficient enzyme coatings. Healthy cells have an enzyme coating around them, which they produce. This coating protects them from free radicals or the action of oxygen. Oxygen starvation at the cellular level is what causes cells to be too weak to manufacture the enzymes that protect them.