"This review examines the variability of the glutathione system in sleep pathologies. Modern sleep theory assumes a restorative sleep function, including active utilization of oxidants and protection from excessive oxidation. In this review article, we conducted an analysis of domestic and foreign literature and summarized data relating aspects of the functioning of the glutathione system in somnological disorders. Various authors have established systemic oxidative stress in insomnia due to reduced activity of glutathione peroxidase. Also, oxidative stress in insomnia is observed in certain areas of the brain due to a decrease in glutathione levels in them. Studies of the functioning of the glutathione system genes in insomnia, whose polymorphisms may include alleles that inhibit oxidation, are arousing interest. An alternative pattern of changes is observed in obstructive sleep apnea syndrome. The apnea stage affects the indicators of the glutathione system. The values of the glutathione system indicators increase with mild to moderate apnea. This is an adaptive response mechanism. Also, the development of oxidative stress in apnea, which leads to disorders in the glutathione system, is cyclical. As a result, people with apnea do not have sufficient replenishment of the components of the glutathione system during sleep. The existing modification does not allow to fully respond to the intensification of peroxide processes and to restrain the activation of excessive oxidation."  Source