In healthy cells and tissue, more than 90% of the total glutathione pool is in the reduced form (GSH) and less than 10% exists in the disulfide form (GSSG). An increased GSSG-to-GSH ratio is considered indicative of oxidative stress.
"Glutathione is a very interesting, very small molecule that's [produced by the body and] found in every cell," says Gustavo Bounous, MD, director of research and development at Immunotec and a retired professor of surgery at McGill University in Montreal, Canada. "It's the [body's] most important antioxidant because it's within the cell."
Antioxidants -- the most well known of which are vitamins C and E -- are important for good health because they neutralize free radicals, which can build up in cells and cause damage. Because glutathione exists within the cells, it is in a prime position to neutralize free radicals. It also has potentially widespread health benefits because it can be found in all types of cells, including the cells of the immune system, whose job is to fight disease.
Glutathione occurs naturally in many foods, and people who eat well probably have enough in their diets, says Dean Jones, PhD, professor of biochemistry and director of nutritional health sciences at Emory University in Atlanta. Those with diets high in fresh fruits and vegetables and freshly prepared meats are most likely just fine. On the other hand, those with poor diets may get too little.