Respiratory-physiology modeling of therapeutic hydrogen inhalation: defining the fraction of inspired hydrogen (FiH2) and flow-rate requirements.
Tyler W LeBaron, Kinji Ohno, Cordélia Salomez-Ihl, Philippe Cinquin, François Boucher, Motoaki Sano, John N Kheir · Respiratory research · 2026
Research-use notice
Independent study record
Each H2HUBB study page organizes source-linked research details for educational use. Interpretation should remain proportional to the study design, population, controls, and limitations.
H2HUBB TAKEAWAY
In order to truly determine and provide minimum/optimal H₂ concentrations, researchers must measure or estimate and report the specific FiH2 based on the provided equations. This source-grounded publication contributes evidence relevant to molecular hydrogen and is retained in a transparent general research category when a more specific study design is not supported by the indexed record.
What the Findings Mean
H2HUBB reviewed how inhaled hydrogen gas was evaluated in this publication and summarizes the source-grounded findings below. Modeling suggests that ~200–300 mL/min absolute hydrogen achieves ~1% FiH2 via nasal cannula in average adults, whereas higher flows (~600–1200 mL/min) may be required for 2–4% and may still fail to reach 1%.
What Effects Did Molecular Hydrogen Have?
Source-reported hydrogen concentration: 0.5% source-reported H₂ gas concentration; Source-reported hydrogen exposure: 0.5% source-reported H₂ gas concentration; 6 L/min total gas flow (approximately 30 mL/min H₂ component). Modeling suggests that ~200–300 mL/min absolute hydrogen achieves ~1% FiH2 via nasal cannula in average adults, whereas higher flows (~600–1200 mL/min) may be required for 2–4% and may still fail to reach 1%. The authors concluded that fiH2 provides the only physiologically meaningful metric for hydrogen dosing because it determines airway partial pressure and tissue concentrations. Molecular hydrogen (H₂ gas) has emerged as a promising therapeutic agent with reported benefits across oxidative stress, inflammation, cardiovascular, and neurodegenerative conditions.
Why These Findings Matter
These findings add evidence supporting molecular hydrogen's therapeutic potential within the biological process and outcomes directly measured in this publication and contribute to the growing body of molecular-hydrogen research.
How Strong Is This Evidence?
H2HUBB classifies this publication as other research and interprets only the outcomes directly supported by the source record.
Technical Study Details
H2HUBB classifies this publication as other research with other supported evidence. The hydrogen delivery method was inhaled hydrogen gas. The source-reported hydrogen concentration was 0.5% source-reported H₂ gas concentration.
Limitations and Safety
Reported limitations: Because the analysis is deterministic, no inferential statistics were applied; uncertainty was explored via bounded parameter variation across physiologically plausible breathing conditions.
Original Study and H2HUBB Research Context
H2HUBB presents this source-grounded research record as one contribution to the broader molecular-hydrogen evidence base.
What the Researchers Studied
The available source identifies this publication as other research. A more specific population or model was not separately reported in the source text available to H2HUBB.