Low-Concentration Hydrogen May Suppress Chronic Inflammation in 'Me-byo': Review by MiZ, UC Berkeley, and Keio University

In July 2021, a joint research group consisting of MiZ Co., Ltd. (Kamakura, Kanagawa), the University of California, Berkeley, and Keio University published a review article suggesting that molecular hydrogen (H2) can suppress chronic inflammation in 'me-byo'—the pre-symptomatic stage of diseases—and contribute to the prevention of various conditions (published in 'International Journal of Molecular Sciences', 2021, Vol. 22, No. 13, 7211).

Key Findings - Molecular hydrogen (H2) selectively removes the highly reactive oxygen species 'hydroxyl radical (•OH)', potentially suppressing the triggers of chronic inflammation at an early stage. - Research suggests that hydrogen may inhibit the over-activation of the 'NLRP3 inflammasome', a central regulator of inflammation. - Hydrogen does not affect other reactive oxygen species necessary for the body, resulting in a reported low risk of side effects. - Broad protective effects were identified in the pre-symptomatic stages of diseases such as Alzheimer's, Parkinson's, chronic kidney disease, diabetes, hypertension, liver disease, and cancer. - Low-concentration hydrogen inhalation, where the device output concentration is kept below the empirical safety threshold of 10 vol%, poses no explosion risk and is suitable for continuous preventive medicine applications.

Background: Chronic Inflammation in Me-byo and Preventive Medicine Many chronic diseases are known to be preceded by persistent, low-level chronic inflammation long before symptoms appear. While suppressing this inflammation during the 'me-byo' stage is crucial for disease prevention and extending healthy life expectancy, methods to safely and continuously control systemic chronic inflammation have been limited. Previously thought to be physiologically inert, molecular hydrogen (H2) is now drawing attention as a promising molecule that can suppress chronic inflammation at the cellular level from the source.

Safety Advocacy: The 10 vol% Standard In 2015, MiZ Co., Ltd. announced that hydrogen concentrations exceeding 10 vol% in daily environments pose an explosion risk, based on literature review and empirical studies simulating inhalation conditions. This 10 vol% figure is an empirical value specifically for inhalation environments, distinct from the classical lower flammability limit (LFL) of 4 vol% defined under ideal conditions. Since hydrogen inhalation environments are open systems—differing fundamentally from closed-system tests in terms of space, mixing, and flow—the company advocates that 10 vol% is the appropriate standard for safety evaluation (Ichikawa et al., 2026).