Trial Report Successful treatment of myalgic encephalomyelitis/chronic fatigue syndrome using hydrogen gas: four case reports, 2023, Hirano

There isn't an abstract, but I think this paragraph serves the purpose:

Molecular hydrogen (H2) is a gaseous molecule that selectively scavenges reactive oxygen and nitrogen species with strong oxidizing power, namely, hydroxyl radicals (·OH) and peroxynitrite, respectively.[11,12] H2 easily crosses the blood-brain barrier and biological membranes, reaches mitochondria, and protects cells from ·OH-induced cell damage.[11,12] A recent literature review revealed that H2 attenuated acute or chronic fatigue in animals and healthy subjects.[13] We also reported that the anti-fatigue effects of H2 involved the protection of mitochondria, which may also ameliorate the pathogenesis of ME/CFS.[13] Therefore, we conducted this case study to test this hypothesis by examining the efficacy of H2 gas inhalation in four patients with ME/CFS.