Glutathione, or GSH, is an antioxidant found in every cell in the body. It is widely known for controlling free radicals. The majority of glutathione in the body is present in its reduced form because this is the only way it can perform its critical role.
The body relies on chemical reactions to break down large molecules into energy and to build small molecules back up into functional elements. Oxidation refers to a chemical reaction where oxygen combines with an atom or molecule. During this process, hydrogen and one or more electrons are lost. Reduction is the reverse chemical reaction, in which oxygen is lost and hydrogen and electrons are gained. In a balanced state, oxidation and reduction go hand-in-hand—there is always a reduction reaction to lock onto any hydrogen and electrons from the oxidation reaction. The shortened term for this is a “redox” reaction.
The process of oxidation produces free radicals. Free radicals are atoms or molecules that have an unpaired electron, which makes them unstable and highly reactive. These atoms and molecules are "looking" to enter into a chemical reaction that will stabilize their electrons. These reactions are vital to the body's health. However, the same free radicals can also cause significant cell damage.
Glutathione protects cells from the free radicals produced through oxidation. It can only do this by remaining in its naturally reduced state so that it is readily available to neutralize free radicals by bonding with them. As GSH bonds it converts to its oxidized form, called glutathione disulfide. Then an enzyme—glutathione reductase—reverts it back to its reduced state. The ratio of reduced GSH to oxidized GSH within the cells can be used to measure cellular toxicity. In healthy cells, 90 percent of the GSH should be in its reduced form.
Since glutathione is so important to maintaining cell health it would seem logical to take supplements to ensure an adequate supply. However, researchers have found that glutathione is not absorbed well through the digestive system. GSH is produced naturally in the body from cysteine, glutamate and glycine. Since cysteine is the building block that enables its participation in redox reactions, the focus for supplements is on using cysteine to ensure the body has sufficient quantities to produce GSH.
Without this powerful antioxidant, the cells in the body would not be protected from oxidative injury. They would be damaged and killed, setting off an inflammation response. GSH also has several other roles. In the liver it helps to transport amino acids across cell membranes so that they can be converted into proteins. It is also essential for the detoxification of acetaminophen, so if the supply of GSH becomes too low, liver toxicity results.