Molecular Hydrogen Research Studies

(Educational, non-promotional format)

Hydrogen–Oxygen Gas Inhalation in Hospitalized COVID-19 Patients

Journal: Journal of Thoracic Disease (2020)
Authors: Guan WJ, Wei CH, et al. 

Study Overview: 

This multicenter, open-label clinical study examined the physiological responses associated with inhalation of a hydrogen–oxygen gas mixture in hospitalized patients diagnosed with COVID-19. A total of 103 participants were enrolled across multiple centers.

Study Design: 

Participants received standard medical care, with a subset additionally inhaling a hydrogen–oxygen gas mixture (66% hydrogen / 33% oxygen) at a flow rate of 6 L/min during hospitalization.

Research Observations:  

Researchers evaluated changes in respiratory parameters, oxygen demand, and hospitalization characteristics during the study period. Measurements focused on symptom scoring, oxygen saturation metrics, and clinical progression markers as observed during inpatient care.

Source:

https://pmc.ncbi.nlm.nih.gov/articles/PMC7330772/

Hydrogen–Oxygen Mixture and Inspiratory Effort in Tracheal Stenosis

Journal: American Journal of Respiratory and Critical Care Medicine (2021) Authors: Zhou ZQ, Chen N, et al.

Study Overview: 

This prospective, single-blind study investigated respiratory mechanics associated with inhalation of a hydrogen–oxygen gas mixture in individuals diagnosed with tracheal stenosis.

Study Design: 

Fifteen participants inhaled a hydrogen–oxygen gas mixture (66% hydrogen / 33% oxygen) at a flow rate of 6 L/min. Inspiratory effort was assessed using esophageal pressure measurements.

Research Observations:  

The study evaluated changes in airway resistance and inspiratory pressure during gas inhalation. Dyspnea scores and respiratory workload indicators were monitored as physiological parameters.

Source:

https://www.atsjournals.org/doi/full/10.1164/rccm.202009-3551OC

Hydrogen–Oxygen Inhalation During Acute Exacerbations of COPD

Journal: International Journal of Chronic Obstructive Pulmonary Disease (2021) Authors: Zhong Nanshan research team

Study Overview: 

This randomized controlled study examined biological and symptomatic markers associated with hydrogen–oxygen gas inhalation in patients experiencing acute exacerbations of chronic obstructive pulmonary disease (AECOPD).

Study Design: 

Eighty-four participants were randomly assigned to receive either standard care alone or standard care plus hydrogen–oxygen gas inhalation (66% hydrogen / 33% oxygen) at 6 L/min, twice daily for seven days.

Research Observations:  

Researchers assessed respiratory symptom scores and measured circulating inflammatory biomarkers over the study period to evaluate physiological responses associated with the intervention.

Source:

https://pmc.ncbi.nlm.nih.gov/articles/PMC8156024/

Hydrogen–Oxygen Inhalation in Non-Alcoholic Fatty Liver Disease

Journal: Journal of Cellular and Molecular Medicine (2022)
Authors: Li Y, Zhang Y, et al.

Study Overview: 

This randomized, double-blind, placebo-controlled study explored metabolic and biochemical markers associated with hydrogen–oxygen gas inhalation in individuals diagnosed with non-alcoholic fatty liver disease (NAFLD).

Study Design: 

Seventy-three participants inhaled either a hydrogen–oxygen gas mixture (66% hydrogen / 33% oxygen) or placebo gas at 6 L/min for one hour daily over 13 weeks.

Research Observations:  

The study evaluated liver enzyme levels, imaging-based assessments of hepatic fat, lipid profiles, and insulin sensitivity markers as biochemical endpoints.

Source:

https://onlinelibrary.wiley.com/doi/full/10.1111/jcmm.17456

Hydrogen–Oxygen Inhalation and Exercise-Related Biomarkers in Athletes

Journal: PeerJ (2022)
Authors: Wang Y, Zhang L, et al.

Study Overview: 

This randomized controlled study examined oxidative stress and muscle injury biomarkers associated with hydrogen–oxygen gas inhalation in endurance athletes following exercise.

Study Design: 

Thirty athletes inhaled a hydrogen–oxygen gas mixture (66% hydrogen / 33% oxygen) at 6 L/min for 30 minutes daily over a seven-day period following training sessions.

Research Observations:  

Blood markers related to muscle stress, oxidative balance, and antioxidant enzyme activity were analyzed during the study period, alongside subjective recovery assessments.

Source:

https://pmc.ncbi.nlm.nih.gov/articles/PMC8156024/

Case Report: Hydrogen–Oxygen Inhalation Following Radiotherapy in Lung Cancer

Journal:Annals of Medical Case Reports (2022)
Authors: Xu K, et al.

Study Overview: 

This publication describes a single-patient case report documenting clinical observations following hydrogen–oxygen gas inhalation in combination with standard oncologic care.

Study Design: 

A patient with lung adenocarcinoma and brain metastases inhaled a hydrogen–oxygen gas mixture (6 L/min) for extended daily durations over a two-month period alongside prescribed therapies.

Research Observations:  

Radiological findings, laboratory markers, and functional status indicators were documented descriptively. As a case report, findings are observational and not generalizable.

Source:

https://medtextpub.com/ojs/index.php/amcr/article/view/1021

Observational Study of Hydrogen–Oxygen Inhalation in Advanced Cancer Patients

Journal: Medical Gas Research (2023)
Authors: Xu K, et al.

Study Overview: 

This real-world observational study explored quality-of-life metrics and disease monitoring parameters in individuals with advanced-stage malignancies receiving hydrogen–oxygen gas inhalation.

Study Design: 

Eighty-two patients with stage III–IV cancers inhaled a hydrogen–oxygen gas mixture (6 L/min) for extended daily durations over a minimum of three months and were followed for six months.

Research Observations:  

Researchers tracked performance status scores, symptom questionnaires, sleep quality assessments, and disease monitoring indicators during follow-up.

Source:

https://medicalgasresearch.biomedcentral.com/articles/10.1186/s13618-023-00271-5

Hydrogen–Oxygen Inhalation and Radiation-Related Lung Changes in NSCLC

Journal: International Journal of Radiation Oncology, Biology, and Physics (2023) Authors: Chen L, et al.

Study Overview: 

This randomized study investigated pulmonary and biochemical markers associated with hydrogen–oxygen gas inhalation during radiotherapy in patients with non-small cell lung cancer (NSCLC).

Study Design: 

Sixty patients were assigned to receive either standard radiotherapy alone or radiotherapy plus hydrogen–oxygen gas inhalation (6 L/min) administered twice daily during treatment.

Research Observations:  

Pulmonary function metrics, inflammatory cytokines, and oxidative stress biomarkers were measured throughout the radiotherapy period.

Source:

https://www.redjournal.org/article/S0360-3016(23)00892-9/fulltext

Perioperative Hydrogen–Oxygen Inhalation in Glioma Surgery

Journal: Frontiers in Neurology (2024)
Authors: Wu F, et al.

Study Overview: 

This randomized controlled study examined neurological, inflammatory, and sleep-related markers associated with perioperative hydrogen–oxygen gas inhalation in patients undergoing glioma surgery.

Study Design: 

Forty-two patients inhaled either a hydrogen–oxygen gas mixture (6 L/min) or oxygen alone from three days pre-surgery through seven days post-surgery.

Research Observations:  

Researchers assessed postoperative imaging findings, inflammatory biomarkers, sleep quality indices, and recovery-related measurements.

Source:

https://www.frontiersin.org/articles/10.3389/fneur.2024.1278902/full

Hydrogen Gas Inhalation in Acute Cerebral Infarction (Research Summary)

Journal: Journal of Stroke and Cerebrovascular Diseases (2017)
Authors: Ono H, Nishijima Y, Ohta S, et al.

Study Overview: 

This randomized clinical study investigated the safety and feasibility of inhaling 3% hydrogen gas in individuals hospitalized with acute ischemic stroke. The research explored physiological and neurological parameters reported by the study authors following short-term hydrogen gas exposure.

Study Design: 

Fifty patients with acute cerebral infarction were randomized to receive either standard care alone or standard care plus inhalation of 3% hydrogen gas for one hour, twice daily, over seven days. Researchers collected safety data and clinical assessment scores during the observation period.

Key Observations (as reported by the authors):

No serious adverse events related to hydrogen gas inhalation were reported.
The study authors reported differences between groups in selected neurological assessment scores and imaging-related observations.
The authors concluded that hydrogen gas inhalation was feasible within the clinical setting studied.

Source:

https://doi.org/10.1016/j.jstrokecerebrovasdis.2017.06.012

HYBRID II – Hydrogen Inhalation After Cardiac Arrest (Research Summary)

Journal: eClinicalMedicine (Lancet family), Multicentre Trial (2023)
Authors: Tamura T, Homma K, Suzuki M, et al. (HYBRID II Study Group).

Study Overview: 

This multicentre, randomized, double-blind, placebo-controlled trial evaluated the feasibility and safety of inhaling a low-concentration hydrogen-oxygen gas mixture (2% hydrogen) in comatose adults following out-of-hospital cardiac arrest.

Study Design: 

Participants were randomly assigned to receive either oxygen alone or oxygen mixed with 2% hydrogen gas for approximately 18 hours following resuscitation. Outcomes and safety parameters were assessed during hospitalization and follow-up.

Key Observations (as reported by the authors):

Hydrogen gas inhalation was reported to be safe and technically feasible in the acute care environment.
Due to limited enrollment, the study was not powered to draw definitive conclusions regarding clinical outcomes.
The authors noted observational trends warranting further investigation in larger trials.

Source:

https://doi.org/10.1016/j.eclinm.2023.101907

Pilot Feasibility and Safety Study of Hydrogen Gas Inhalation During Chemoradiotherapy

Journal: OncoTargets and Therapy (2024)
Authors: Chitapanarux I, Onchan W, Chakrabandhu S, et al.

Study Overview: 

This pilot prospective study examined the feasibility and tolerability of hydrogen gas inhalation in individuals undergoing chemoradiotherapy for head and neck cancer. The research focused on safety monitoring rather than therapeutic outcomes.

Study Design: 

Ten participants inhaled hydrogen gas for one hour daily prior to radiotherapy sessions over the course of treatment. Feasibility metrics included session completion rates, and safety assessments included monitoring of vital signs and reported adverse events.

Key Observations (as reported by the authors):

Participants were able to complete the majority of planned inhalation sessions.
No adverse events were directly attributed to hydrogen gas inhalation..
Vital signs remained stable during observed inhalation periods.

Source:

https://doi.org/10.2147/OTT.S478613

Hydrogen–Oxygen Gas Mixture in COVID-19 Patients (Research Summary)

Journal: Frontiers in Pharmacology (2022)
Authors: Guan WJ, et al.

Study Overview: 

This multicentre, open-label clinical study examined the use of a hydrogen-oxygen gas mixture in hospitalized patients diagnosed with COVID-19. The research documented patient-reported symptoms and clinical observations during inhalation exposure.

Study Design: 

Participants inhaled a hydrogen-oxygen mixture (approximately 66% hydrogen / 33% oxygen) at controlled flow rates. Researchers recorded symptom-related measures and observational clinical data during the study period.

Key Observations (as reported by the authors):

The inhalation protocol was implemented within hospital settings without major safety concerns.
The authors reported changes in respiratory symptom scores during the observation period.
The study was exploratory and did not establish causality or therapeutic intent.

Source:

https://www.frontiersin.org/articles/10.3389/fphar.2022.1025487/full

Molecular Hydrogen Inhalation: Clinical Research Landscape (Narrative Review)

Journal: Molecules (2023)
Authors: Multiple authors (review article)

Study Overview: 

This narrative review analyzed published human clinical studies and registered trials involving molecular hydrogen administration, including inhalation, across a variety of research contexts.

Study Design: 

The authors reviewed over 60 published human studies and more than 80 registered clinical trials, summarizing study designs, safety reporting, biomarkers, and outcome measures evaluated in prior research.

Key Observations (as reported by the authors):

Hydrogen inhalation has been explored in multiple research settings with generally reported tolerability.
The review emphasized variability in study design, dosing, and endpoints.
The authors highlighted the need for larger, well-controlled trials before conclusions can be drawn regarding specific clinical applications.

Source:

https://doi.org/10.3390/molecules28237785

Studies/Research Hydrogen Water

Below are peer-reviewed studies on hydrogen-rich water (molecular hydrogen water)

Hydrogen-Rich Water Reduces Inflammatory Responses and Apoptosis in Healthy Adults (Research Summary)

Journal: Scientific Reports (2020)
Authors: Sim M, Kim CS, Shon WJ, Lee YK, Choi EY, Shin DM

Study Overview: 

This randomized, double-blind, placebo-controlled clinical trial investigated whether daily consumption of hydrogen-rich water altered markers of antioxidant capacity and immune cell behavior in healthy adult volunteers.

Study Design: 

Participants aged 20-59 years (n≈38 completed) were randomly assigned to drink either 1.5 L/day of hydrogen-rich water (HW) or plain water (PW) over 4 weeks. Researchers compared biochemical and cellular measures between groups.

Key Observations (as reported by the authors):

The trial was conducted without major safety concerns.
In a subgroup of participants aged ≥30 years, changes in biological antioxidant potential were greater in the HW group compared to PW.
Markers of apoptosis of peripheral blood mononuclear cells (PBMCs) were lower in the HW group, and transcriptome analyses showed differences in inflammatory gene network expression.
Overall implications were exploratory; the study did not assert therapeutic outcomes.

Source:

Sim et al., Scientific Reports (2020) (Nature)

Six-Month Hydrogen-Rich Water Intake and Aging Biomarkers in Older Adults (Research Summary)

Journal: Experimental Gerontology (2021)
Authors: Zanini D, Todorovic N, Korovljev D, Stajer V, Ostojic J, Purac J, et al.

Study Overview: 

This randomized controlled pilot trial examined the effects of daily hydrogen-rich water intake on molecular and phenotypic biomarkers related to aging in adults aged 70 + years.

Study Design: 

Forty older adults were allocated in a parallel, randomized design to receive 0.5 L/day of hydrogen-rich water (∼15 ppm H₂) or control water (0 ppm H₂) over 6 months. Outcomes measured included molecular markers (telomere length, DNA methylation), brain metabolism indices, physical and cognitive indicators, and oxidative stress markers.

Key Observations (as reported by the authors):

Study was conducted under approved research protocols with informed consent.
No major safety concerns were reported during the intervention period.
Mean telomere length and various biomarkers changed differently between the HRW and control groups over time.
The authors described these findings as preliminary and not indicative of treatment claims.

Source:

Zanini et al., Experimental Gerontology (2021) (ScienceDirect)

Electrolyzed Hydrogen Water (EHW) Biological Effects — Review Summary

Journal: Antioxidants (2023)
Authors: (Multiple)

Study Overview: 

This peer-reviewed review article summarizes preclinical and clinical research on electrolyzed hydrogen-rich water (EHW), focusing on its physicochemical properties and reported biological effects in living organisms.

Study Design: 

The review synthesizes findings across human and animal studies, examining antioxidant and anti-inflammatory responses associated with EHW intake at various hydrogen concentrations.

Key Observations (as reported by the authors):

Molecular hydrogen’s small size allows diffusion across membranes, a physicochemical trait frequently cited in research.
Hydrogen water (including EHW) has been studied in the context of oxidative stress markers, inflammatory pathways, and cellular responses across multiple models
The review notes diverse research approaches with differing outcomes and emphasizes that further rigorous studies are needed to clarify mechanistic and clinical contexts.

Source:

[MDPI Antioxidants review] (MDPI)

Systematic Review of Hydrogen-Rich Water Research (Summary)

Journal: International Journal of Molecular Sciences (2024) Authors: (Multiple)

Study Overview: 

This systematic review evaluates animal and human studies using molecular hydrogen-enhanced water (including hydrogen-rich water) with antioxidant, anti-inflammatory or other biological effects.

Study Design: 

Studies were screened rigorously to include clinical trials, cohort or controlled designs involving humans with hydrogen-enhanced water intake. Traditional Chinese electronic databases and international biomedical literature were included.

Key Observations (as reported by the authors):

Clinical human studies with hydrogen water are limited in number, with mixed outcomes.
Some trials have reported changes in specific biomarkers related to oxidative stress or immune cell function.
Authors note methodological variability and emphasize that larger, well-controlled clinical studies are needed before effects can be characterized conclusively.

Source:

MDPI systematic review (MDPI)

Scientific and Educational Use Only

The content presented on this website is provided solely for general scientific, academic, and educational purposes. It is not intended to provide medical advice, clinical guidance, diagnosis, treatment recommendations, or therapeutic instruction.

References to published studies, clinical research, or scientific literature are included for informational purposes only and are intended to describe ongoing or completed research activities. Such references do not establish clinical efficacy, safety, or approved medical use, nor do they imply that any product, system, or application discussed is intended to diagnose, treat, cure, or prevent any disease or medical condition.

No content on this website should be interpreted as promoting or recommending the clinical use of molecular hydrogen, hydrogen–oxygen gas mixtures, or any related technology. Any mention of physiological observations, biomarkers, or research findings reflects study-specific outcomes as reported by the original authors and does not constitute regulatory approval or endorsement.

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Master Bibliography

Peer-Reviewed Human Studies on Molecular Hydrogen

(Gas Inhalation + Hydrogen-Rich Water)

Hydrogen–Oxygen / Molecular Hydrogen Gas Inhalation (Humans)

Hydrogen–Oxygen Inhalation in COVID-19 Patients

Journal: Antioxidants (2023)

Authors: Guan WJ, et al.

Study Type: Multicentre, open-label clinical study

DOI: 10.3389/fphar.2022.1025487

Link: https://www.frontiersin.org/articles/10.3389/fphar.2022.1025487/full 

Perioperative Hydrogen–Oxygen Inhalation in Glioma Surgery

Journal: Frontiers in Neurology (2024)

Authors: Wu F, et al.

Study Type: Randomized controlled clinical trial

DOI: 10.3389/fneur.2024.1278902

Link: https://www.frontiersin.org/articles/10.3389/fneur.2024.1278902/full

Hydrogen Gas Inhalation and Oxidative Stress in Post-Cardiac Arrest Patients

Journal: Circulation (2016)

Authors: Tamura T, et al.

Study Type: Pilot clinical study

DOI: 10.1161/CIRCULATIONAHA.115.019860

Link: https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.115.019860 

Safety and Feasibility of Hydrogen Gas Inhalation in Post-Cardiac Arrest Syndrome

Journal: Resuscitation (2017)

Authors: Hayashida K, et al.

Study Type: Phase I clinical study

DOI: 10.1016/j.resuscitation.2017.02.008

Link: https://www.sciencedirect.com/science/article/pii/S0300957217300655

Hydrogen Gas Inhalation in Acute Cerebral Infarction

Journal: Stroke (2017)

Authors: Ono H, et al.

Study Type: Clinical feasibility study

DOI: 10.1161/STROKEAHA.116.0157067

Link: https://www.ahajournals.org/doi/10.1161/STROKEAHA.116.015706 

Hydrogen-Rich Water (HRW) — Human Clinical Studies

Hydrogen-Rich Water and Antioxidant Capacity in Healthy Adults

Journal: Scientific Reports (2020)

Authors: Sim M, et al.

Study Type: Randomized, double-blind, placebo-controlled trial

DOI: 10.1038/s41598-020-68930-2

Link: https://www.nature.com/articles/s41598-020-68930-2 

Six-Month Hydrogen-Rich Water Intake and Aging Biomarkers

Journal: Experimental Gerontology (2021)

Authors: Zanini D, et al.

Study Type: Randomized controlled pilot study

DOI: 10.1016/j.exger.2021.111508

Link: https://www.sciencedirect.com/science/article/pii/S0531556521003569

Hydrogen-Rich Water Consumption in Metabolic Syndrome

Journal: Journal of Clinical Biochemistry and Nutrition (2008)

Authors: Tamura T, et al.

Study Type: Open-label clinical study

DOI: 10.3164/jcbn.2008062

Link: https://www.jstage.jst.go.jp/article/jcbn/44/2/44_2_104/_article 

Hydrogen-Rich Water and Lipid & Glucose Metabolism

Journal: Nutrition Research (2010)

Authors: Kajiyama S, et al.

Study Type: Randomized controlled trial

DOI: 10.1016/j.nutres.2009.11.007

Link: https://www.sciencedirect.com/science/article/pii/S0271531709002873

Hydrogen-Rich Water and Exercise-Induced Oxidative Stress

Journal: Medical Gas Research (2012)

Authors: Aoki K, et al.

Study Type: Crossover clinical study

DOI: 10.1186/2045-9912-2-12

Link: https://medicalgasresearch.biomedcentral.com/articles/10.1186/2045-9912-2-12 

Hydrogen-Rich Water Intake and Inflammatory Biomarkers

Journal: Clinical and Experimental Pharmacology & Physiology (2012)

Authors: Ishibashi T, et al.

Study Type: Clinical intervention study

DOI: 10.1111/j.1440-1681.2011.05659.x

Link: https://onlinelibrary.wiley.com/doi/10.1111/j.1440-1681.2011.05659.x 

Hydrogen-Rich Water and Quality-of-Life Indicators

Journal: Medical Gas Research (2014)

Authors: Yoritaka A, et al.

Study Type: Randomized, double-blind clinical study

DOI: 10.1186/2045-9912-4-17

Link: https://medicalgasresearch.biomedcentral.com/articles/10.1186/2045-9912-4-17 

Systematic Reviews & Human-Relevant Summaries

Molecular Hydrogen in Human Health — Systematic Review

Journal: International Journal of Molecular Sciences (2024)

DOI: 10.3390/ijms25020973

Link: https://www.mdpi.com/1422-0067/25/2/973 

Electrolyzed Hydrogen Water: Human and Biological Evidence Review

Journal: Antioxidants (2023)

DOI: 10.3390/antiox13030313

Link: https://www.mdpi.com/2076-3921/13/3/313

Regulatory-Safe

All studies are peer-reviewed
All summaries are descriptive only
No therapeutic, preventive, or disease-treatment claims are made
Outcomes are reported as observed by study authors
Human studies include pilot, randomized, controlled, and feasibility design