Low-Concentration Hydrogen Inhalation Suppresses Bone Marrow Damage from Radiation Therapy: Significantly Reduces Leukopenia and Thrombocytopenia | MiZ & 5 Institutions Joint Research
MiZ Corporation and a joint research group have clinically demonstrated that low-concentration hydrogen inhalation significantly suppresses leukopenia and thrombocytopenia in cancer patients undergoing Intensity-Modulated Radiation Therapy (IMRT). This research highlights the importance of safe, low-concentration hydrogen inhalation for mitigating radiation therapy side effects.
📋 Article Processing Timeline
- 📰 Published: May 11, 2026 at 19:40
- 🔍 Collected: May 11, 2026 at 11:01
- 🤖 AI Analyzed: May 11, 2026 at 11:45 (44 min after Collected)
Lead Paragraph
MiZ Corporation (Kamakura, Kanagawa Prefecture) and a joint research group comprising Clinic C4, National Center for Child Health and Development, Osaka University Graduate School of Medicine, Kansai Medical Hospital, and Keio University, clinically demonstrated in 2021 that inhaling low-concentration hydrogen gas (5% by volume) for 30 minutes significantly suppressed leukopenia (P=0.0011) and thrombocytopenia (P=0.0275) in cancer patients undergoing Intensity-Modulated Radiation Therapy (IMRT). This research was published in 'Medical Gas Research' Vol. 11, No. 3, 2021. Furthermore, in January 2026, MiZ Corporation published a paper on hydrogen explosion in the human body (Ichikawa et al., 2026). Based on these findings, this press release reiterates the recommendation that hydrogen inhalation for the purpose of reducing radiation therapy side effects should be performed with low-concentration hydrogen inhalation that can eliminate explosion risks.
Summary of this Release
- Inhalation of low-concentration hydrogen gas (5% by volume) for 30 minutes after IMRT significantly suppressed leukopenia (P=0.0011) and thrombocytopenia (P=0.0275).
- Hydrogen inhalation mitigated only side effects without impairing anti-tumor effects.
- The joint research institutions patented this research outcome as a "radioprotective agent."
- Low-concentration hydrogen inhalation, maintaining hydrogen concentration below 10% by volume, is free from explosion risk and is a safe hydrogen inhalation method applicable in clinical settings.
Background: Side Effects of Radiation Therapy and the Role of Hydrogen Molecules
Intensity-Modulated Radiation Therapy (IMRT) is a standard technique that concentrates radiation on tumors, but bone marrow damage leading to leukopenia and thrombocytopenia remains a challenge in cases requiring wide-field irradiation. Safe and effective preventive agents for this were limited. The mechanism by which radiation kills cancer cells is broadly divided into direct action, where radiation directly damages DNA, and indirect action, where hydroxyl radicals (•OH) generated by the radiolysis of water molecules in the body attack DNA. Hydrogen molecules (H₂) selectively react with •OH to convert them into water molecules (H₂O), which does not interfere with direct action but has been suggested to alleviate oxidative stress in normal tissues associated with indirect action (Figure 1).
Figure 1: Main Mechanisms of Radiation Action on Cancer Cells
On the other hand, MiZ Corporation announced in 2015, based on a thorough review of existing literature and empirical studies assuming an inhalation environment, that there is a risk of explosion if the hydrogen concentration exceeds 10% by volume in daily environments. The value of 10% by volume is an empirical value derived from an inhalation environment, distinct from the lower explosion limit of hydrogen defined under ideal conditions (Ichikawa et al., 2026).
Definition of Terms
Intensity-Modulated Radiation Therapy (IMRT): A modern radiation therapy technique that concentrates radiation on tumors and minimizes exposure to surrounding normal tissues. Bone marrow damage still remains a challenge in cases requiring wide-field irradiation.
Radiation-Induced Bone Marrow Damage: A side effect of radiation therapy where bone marrow cells (hematopoietic stem cells and progenitor cells) are damaged, leading to a decrease in white blood cell and platelet counts. This increases the risk of infection and bleeding, making it difficult to continue treatment.
Hydroxyl Radical (•OH): The most potent oxidizing radical among reactive oxygen species. In vivo, it is generated by the radiolysis of water molecules and oxygen metabolism in mitochondria. It indiscriminately attacks DNA, proteins, and lipids, and no endogenous enzymes exist to eliminate it.
Hydrogen Inhaler: A device that generates hydrogen gas (H₂) using water electrolysis and delivers it into the body via the respiratory system. The selection of the device's output concentration is a design variable that determines safety. MiZ Corporation advocates for a design that maintains the device output concentration below the empirically proven inhalation environment value of 10% by volume (Ichikawa et al., 2026).
Empirical Inhalation Environment Value (10% by volume): The empirically proven threshold for explosion risk in a hydrogen inhalation environment (exceeding 10% by volume). This value was announced by MiZ Corporation in 2015, based on a thorough review of existing literature and empirical studies assuming an inhalation environment, taking into account inhalation-specific conditions such as device outlet, exhalation pathway, human body, and device design (Ichikawa et al., 2026).
Classical Lower Flammability Limit (LFL) 4% by volume: A value reported by Coward & Jones (1952) in U.S. Bureau of Mines Bulletin 503. It is the theoretical minimum concentration measured as the lowest concentration at which upward flame propagation can continuously occur when hydrogen and air are premixed in a closed vertical tube at 1 atmosphere and room temperature, and ignited in a static state. It primarily targets confined scenarios such as containers, piping, and mines.
Relationship between LFL 4% and Empirical Value 10%: A hydrogen inhalation environment is an open system that continuously releases hydrogen gas generated by water electrolysis at atmospheric pressure into the atmosphere, continuously diffuses and dilutes it with indoor air, and supplies it as a flowing gas to the inhalation pathway. This differs from premixed static gas in containers and piping.
MiZ Corporation (Kamakura, Kanagawa Prefecture) and a joint research group comprising Clinic C4, National Center for Child Health and Development, Osaka University Graduate School of Medicine, Kansai Medical Hospital, and Keio University, clinically demonstrated in 2021 that inhaling low-concentration hydrogen gas (5% by volume) for 30 minutes significantly suppressed leukopenia (P=0.0011) and thrombocytopenia (P=0.0275) in cancer patients undergoing Intensity-Modulated Radiation Therapy (IMRT). This research was published in 'Medical Gas Research' Vol. 11, No. 3, 2021. Furthermore, in January 2026, MiZ Corporation published a paper on hydrogen explosion in the human body (Ichikawa et al., 2026). Based on these findings, this press release reiterates the recommendation that hydrogen inhalation for the purpose of reducing radiation therapy side effects should be performed with low-concentration hydrogen inhalation that can eliminate explosion risks.
Summary of this Release
- Inhalation of low-concentration hydrogen gas (5% by volume) for 30 minutes after IMRT significantly suppressed leukopenia (P=0.0011) and thrombocytopenia (P=0.0275).
- Hydrogen inhalation mitigated only side effects without impairing anti-tumor effects.
- The joint research institutions patented this research outcome as a "radioprotective agent."
- Low-concentration hydrogen inhalation, maintaining hydrogen concentration below 10% by volume, is free from explosion risk and is a safe hydrogen inhalation method applicable in clinical settings.
Background: Side Effects of Radiation Therapy and the Role of Hydrogen Molecules
Intensity-Modulated Radiation Therapy (IMRT) is a standard technique that concentrates radiation on tumors, but bone marrow damage leading to leukopenia and thrombocytopenia remains a challenge in cases requiring wide-field irradiation. Safe and effective preventive agents for this were limited. The mechanism by which radiation kills cancer cells is broadly divided into direct action, where radiation directly damages DNA, and indirect action, where hydroxyl radicals (•OH) generated by the radiolysis of water molecules in the body attack DNA. Hydrogen molecules (H₂) selectively react with •OH to convert them into water molecules (H₂O), which does not interfere with direct action but has been suggested to alleviate oxidative stress in normal tissues associated with indirect action (Figure 1).
Figure 1: Main Mechanisms of Radiation Action on Cancer Cells
On the other hand, MiZ Corporation announced in 2015, based on a thorough review of existing literature and empirical studies assuming an inhalation environment, that there is a risk of explosion if the hydrogen concentration exceeds 10% by volume in daily environments. The value of 10% by volume is an empirical value derived from an inhalation environment, distinct from the lower explosion limit of hydrogen defined under ideal conditions (Ichikawa et al., 2026).
Definition of Terms
Intensity-Modulated Radiation Therapy (IMRT): A modern radiation therapy technique that concentrates radiation on tumors and minimizes exposure to surrounding normal tissues. Bone marrow damage still remains a challenge in cases requiring wide-field irradiation.
Radiation-Induced Bone Marrow Damage: A side effect of radiation therapy where bone marrow cells (hematopoietic stem cells and progenitor cells) are damaged, leading to a decrease in white blood cell and platelet counts. This increases the risk of infection and bleeding, making it difficult to continue treatment.
Hydroxyl Radical (•OH): The most potent oxidizing radical among reactive oxygen species. In vivo, it is generated by the radiolysis of water molecules and oxygen metabolism in mitochondria. It indiscriminately attacks DNA, proteins, and lipids, and no endogenous enzymes exist to eliminate it.
Hydrogen Inhaler: A device that generates hydrogen gas (H₂) using water electrolysis and delivers it into the body via the respiratory system. The selection of the device's output concentration is a design variable that determines safety. MiZ Corporation advocates for a design that maintains the device output concentration below the empirically proven inhalation environment value of 10% by volume (Ichikawa et al., 2026).
Empirical Inhalation Environment Value (10% by volume): The empirically proven threshold for explosion risk in a hydrogen inhalation environment (exceeding 10% by volume). This value was announced by MiZ Corporation in 2015, based on a thorough review of existing literature and empirical studies assuming an inhalation environment, taking into account inhalation-specific conditions such as device outlet, exhalation pathway, human body, and device design (Ichikawa et al., 2026).
Classical Lower Flammability Limit (LFL) 4% by volume: A value reported by Coward & Jones (1952) in U.S. Bureau of Mines Bulletin 503. It is the theoretical minimum concentration measured as the lowest concentration at which upward flame propagation can continuously occur when hydrogen and air are premixed in a closed vertical tube at 1 atmosphere and room temperature, and ignited in a static state. It primarily targets confined scenarios such as containers, piping, and mines.
Relationship between LFL 4% and Empirical Value 10%: A hydrogen inhalation environment is an open system that continuously releases hydrogen gas generated by water electrolysis at atmospheric pressure into the atmosphere, continuously diffuses and dilutes it with indoor air, and supplies it as a flowing gas to the inhalation pathway. This differs from premixed static gas in containers and piping.