Abstract
Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a disorder that is characterized by fatigue that persists for more than 6 months, weakness, sleep disturbances, and cognitive dysfunction. There are multiple possible etiologies for ME/CFS, among which mitochondrial dysfunction plays a major role in abnormal energy metabolism. The potential of many substances for the treatment of ME/CFS has been examined; however, satisfactory outcomes have not yet been achieved. The development of new substances for curative, not symptomatic, treatments is desired. Molecular hydrogen (H(2)) ameliorates mitochondrial dysfunction by scavenging hydroxyl radicals, the most potent oxidant among reactive oxygen species. Animal experiments and clinical trials reported that H(2) exerted ameliorative effects on acute and chronic fatigue. Therefore, we conducted a literature review on the mechanism by which H(2) improves acute and chronic fatigue in animals and healthy people and showed that the attenuation of mitochondrial dysfunction by H(2) may be involved in the ameliorative effects. Although further clinical trials are needed to determine the efficacy and mechanism of H(2) gas in ME/CFS, our literature review suggested that H(2) gas may be an effective medical gas for the treatment of ME/CFS.