A free radical is an extremely active and unstable atomic or molecular group with a pair of electrons, such as: •O2-, •OH, 1O2 (singlet oxygen), •OOH, etc. Free genes, which have no pair of electrons and are highly unstable, roam the body like vagabonds and do damage; SOD can generously transfer electrons to free radicals, allowing them to pair and settle down without causing damage.
If the body is short of SOD, free radicals pair up by attacking normal cells and stealing electrons, and they undergo a chain reaction and continue until key molecules are destroyed, which leads to the destruction of normal cells and even the destruction of genes, leading to human aging and various diseases. Therefore, free radicals are known as the source of all diseases.