Mechanism of Improvement in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) by Low-Concentration Hydrogen Inhalation
MiZ Co., Ltd. and Keio University explained the mechanism by which low-concentration hydrogen inhalation improves ME/CFS symptoms. They warned against the explosion risks of high-concentration hydrogen and advocated for safe low-concentration therapies based on clinical cases.
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- 📰 Published: April 23, 2026 at 19:05
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MiZ Co., Ltd. (Headquarters: Kamakura City, Kanagawa Prefecture) and a research group from Keio University have published two peer-reviewed academic papers as reviews and case reports regarding the improvement effects of hydrogen inhalation on Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) (Front Neurol. 13: 841310, 2022 / Med Gas Res. 14: 84-86, 2024) (Notes 1, 2).
Furthermore, in January 2026, the same research group published a paper in the peer-reviewed academic journal 'International Journal of Risk and Safety in Medicine' (SAGE Publishing) that investigated a human internal hydrogen explosion accident caused by a high-concentration hydrogen inhaler. They sounded the alarm about the dangers of high-concentration hydrogen inhalers and proposed a shift to low-concentration hydrogen inhalation, which does not carry an explosion risk (Notes 3, 4).
In this press release, we will once again detail the mechanism by which low-concentration hydrogen inhalation improves ME/CFS. Additionally, since ME/CFS patients are often bedridden for long periods, we will concurrently consider the risks associated with high-concentration hydrogen inhalation during sleep.
1. Oxidative stress is a potential major cause of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)
Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a disease that has been covered in the news because it shares many commonalities with post-acute sequelae of COVID-19 and poor physical condition following vaccination. Characteristically, it is accompanied by various physical and mental symptoms in addition to severe fatigue lasting more than 6 months. The cause of the onset has not been elucidated, and more than 40 years have passed without an established treatment.
Previous research has shown that severe inflammation occurs in specific areas of the brains of ME/CFS patients (Nakatomi Y et al. J Nucl Med. 2014) (Figure 1).
- Inflammation of the amygdala: Leads to cognitive decline and impaired judgment
- Inflammation of the hippocampus: Causes severe anxiety and depressive symptoms
- Inflammation of the thalamus: Leads to headaches, muscle pain, and hyperesthesia
The fundamental cause of these inflammations is thought to be excessive oxidative stress caused by 'hydroxyl radicals (•OH)', a harmful active oxygen generated from mitochondria in cells.
Figure 1: Correlation between brain inflammation and symptoms in ME/CFS
2. Hydrogen can react with hydroxyl radicals, converting them to water molecules, potentially alleviating ME/CFS symptoms
Hydrogen molecules (H₂) exhibit antioxidant effects by reacting with hydroxyl radicals (•OH) and converting them into water molecules. In addition, because hydrogen is the smallest diatomic molecule in nature, it freely permeates cell membranes and the blood-brain barrier, quickly spreading throughout the body including the brain, and is excreted from the body by diffusion, meaning it does not accumulate in the body.
Even at low concentrations, hydrogen contains an extremely large number of molecules as a gas, so it is considered that a sufficient amount is supplied to eliminate hydroxyl radicals in the brain. Therefore, there is little rationality in using high-concentration hydrogen, which carries an explosion risk, and it is thought that even low-concentration hydrogen inhalation with guaranteed safety can contribute to the improvement of ME/CFS symptoms (Figure 2).
Figure 2: Hydrogen molecules can eliminate hydroxyl radicals generated in the brain, contributing to the improvement of ME/CFS symptoms. Even low-concentration hydrogen inhalation can supply the number of hydrogen molecules necessary for elimination to the brain.
3. Cases and patents of ME/CFS improvement by low-concentration hydrogen inhalation (5%)
In a 2024 case report (Med Gas Res. 14: 84-86, 2024), MiZ Co., Ltd., with the cooperation of medical institutions, conducted observational follow-ups on 10 ME/CFS patients using low-concentration hydrogen gas inhalation (hydrogen concentration approx. 5%, hydrogen generation volume 200 mL/min). Below are four representative cases where significant improvement was confirmed.
Note that PS (Performance Status) in the cases is an index that evaluates the severity of daily life activities in ME/CFS from 0 to 9, with larger numbers indicating higher severity. PEM (Post-Exertional Malaise) refers to a state where symptoms worsen significantly after exertion, which is considered a core characteristic of ME/CFS.
Case 1: Recovery from poor physical condition after COVID-19 vaccination
Main symptoms: Severe fatigue, sleep disorders, whole-body pain, decreased concentration, dizziness upon standing, hypersensitivity to light, sound, smell, and chemicals.
Progress: Started inhaling 5% concentration hydrogen for 11.5 hours a day from July 2022. Within 2-3 months, symptoms that hindered daily life improved significantly, and by December, subjective symptoms were greatly reduced. The prolonged low-concentration hydrogen inhalation contributed to the alleviation of various symptoms.
Furthermore, in January 2026, the same research group published a paper in the peer-reviewed academic journal 'International Journal of Risk and Safety in Medicine' (SAGE Publishing) that investigated a human internal hydrogen explosion accident caused by a high-concentration hydrogen inhaler. They sounded the alarm about the dangers of high-concentration hydrogen inhalers and proposed a shift to low-concentration hydrogen inhalation, which does not carry an explosion risk (Notes 3, 4).
In this press release, we will once again detail the mechanism by which low-concentration hydrogen inhalation improves ME/CFS. Additionally, since ME/CFS patients are often bedridden for long periods, we will concurrently consider the risks associated with high-concentration hydrogen inhalation during sleep.
1. Oxidative stress is a potential major cause of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)
Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a disease that has been covered in the news because it shares many commonalities with post-acute sequelae of COVID-19 and poor physical condition following vaccination. Characteristically, it is accompanied by various physical and mental symptoms in addition to severe fatigue lasting more than 6 months. The cause of the onset has not been elucidated, and more than 40 years have passed without an established treatment.
Previous research has shown that severe inflammation occurs in specific areas of the brains of ME/CFS patients (Nakatomi Y et al. J Nucl Med. 2014) (Figure 1).
- Inflammation of the amygdala: Leads to cognitive decline and impaired judgment
- Inflammation of the hippocampus: Causes severe anxiety and depressive symptoms
- Inflammation of the thalamus: Leads to headaches, muscle pain, and hyperesthesia
The fundamental cause of these inflammations is thought to be excessive oxidative stress caused by 'hydroxyl radicals (•OH)', a harmful active oxygen generated from mitochondria in cells.
Figure 1: Correlation between brain inflammation and symptoms in ME/CFS
2. Hydrogen can react with hydroxyl radicals, converting them to water molecules, potentially alleviating ME/CFS symptoms
Hydrogen molecules (H₂) exhibit antioxidant effects by reacting with hydroxyl radicals (•OH) and converting them into water molecules. In addition, because hydrogen is the smallest diatomic molecule in nature, it freely permeates cell membranes and the blood-brain barrier, quickly spreading throughout the body including the brain, and is excreted from the body by diffusion, meaning it does not accumulate in the body.
Even at low concentrations, hydrogen contains an extremely large number of molecules as a gas, so it is considered that a sufficient amount is supplied to eliminate hydroxyl radicals in the brain. Therefore, there is little rationality in using high-concentration hydrogen, which carries an explosion risk, and it is thought that even low-concentration hydrogen inhalation with guaranteed safety can contribute to the improvement of ME/CFS symptoms (Figure 2).
Figure 2: Hydrogen molecules can eliminate hydroxyl radicals generated in the brain, contributing to the improvement of ME/CFS symptoms. Even low-concentration hydrogen inhalation can supply the number of hydrogen molecules necessary for elimination to the brain.
3. Cases and patents of ME/CFS improvement by low-concentration hydrogen inhalation (5%)
In a 2024 case report (Med Gas Res. 14: 84-86, 2024), MiZ Co., Ltd., with the cooperation of medical institutions, conducted observational follow-ups on 10 ME/CFS patients using low-concentration hydrogen gas inhalation (hydrogen concentration approx. 5%, hydrogen generation volume 200 mL/min). Below are four representative cases where significant improvement was confirmed.
Note that PS (Performance Status) in the cases is an index that evaluates the severity of daily life activities in ME/CFS from 0 to 9, with larger numbers indicating higher severity. PEM (Post-Exertional Malaise) refers to a state where symptoms worsen significantly after exertion, which is considered a core characteristic of ME/CFS.
Case 1: Recovery from poor physical condition after COVID-19 vaccination
Main symptoms: Severe fatigue, sleep disorders, whole-body pain, decreased concentration, dizziness upon standing, hypersensitivity to light, sound, smell, and chemicals.
Progress: Started inhaling 5% concentration hydrogen for 11.5 hours a day from July 2022. Within 2-3 months, symptoms that hindered daily life improved significantly, and by December, subjective symptoms were greatly reduced. The prolonged low-concentration hydrogen inhalation contributed to the alleviation of various symptoms.