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Effects of Hydrogen Gas Inhalation on Community-Dwelling Adults of Various Ages: A Single-Arm, Open-Label, Prospective Clinical Trial.

水素ガス吸入が地域在住の様々な年齢層の成人に与える影響：単群・非盲検・前向き臨床試験

human observational study inhalation positive

Abstract

This prospective single-arm study enrolled 54 community-dwelling adults of varying ages to examine the effects of 4-week hydrogen gas inhalation. White blood cell counts (total and differential) remained within normal ranges after the intervention, supporting the safety and tolerability of the protocol. Oxidative stress indicators, specifically reactive oxygen species and nitric oxide, declined following the inhalation period. Dementia-associated biomarkers—including BACE-1, amyloid beta, BDNF, VEGF-A, T-tau, MCP-1, and interleukin-6—showed improvement in the majority of participants, suggesting a beneficial effect on cognitive status. The findings indicate that hydrogen gas inhalation warrants further investigation as a candidate approach for addressing cognitive dysfunction associated with Alzheimer's disease in general adult populations.

Mechanism

Hydrogen gas inhalation appears to reduce reactive oxygen species and nitric oxide levels while modulating Alzheimer's disease-related biomarkers such as BACE-1, amyloid beta, T-tau, and inflammatory cytokines, collectively contributing to improved cognitive function.

Bibliographic

Authors
Rahman MH, Bajgai J, Sharma S, Jeong ES, Goh SH, Jang YG, et al.
Journal
Antioxidants (Basel)
Year
2023 (2023-06-08)
PMID
37371971
DOI
10.3390/antiox12061241
PMC
PMC10295751

Tags

Disease:Alzheimer's disease (27) cognitive decline (111) Delivery:inhalation delivery (196) Mechanism:hydroxyl radical scavenging (352) anti-inflammatory (743) oxidative stress (899) reactive oxygen species (774)

Delivery context

In air, molecular hydrogen is reported to be combustible across approximately **4% (LFL, lower flammability limit) to 75% (UFL, upper flammability limit)**. Among high-concentration hydrogen inhalers, 66% output sits inside this range, and even pure-hydrogen (100%) output forms a 4–75% concentration-gradient layer at the device–air boundary (the UFL 75% paradox). Engineering principle would therefore call for operation below LFL (the classical 4%); that figure, however, was measured under closed, pre-mixed, static conditions. For the open, dynamic inhalation environment, the empirical value reported in the literature is **10%**, which is the figure referenced in practice as the operating ceiling. The 66% / 100% output devices are recorded in the Japanese Consumer Affairs Agency accident-information database, and from these considerations are not recommended.

→ Evidence by delivery route

Safety notes

In air, molecular hydrogen is reported to be combustible across approximately **4% (LFL, lower flammability limit) to 75% (UFL, upper flammability limit)**. Among high-concentration hydrogen inhalers, 66% output sits inside this range, and even pure-hydrogen (100%) output forms a 4–75% concentration-gradient layer at the device–air boundary (the UFL 75% paradox). Engineering principle would therefore call for operation below LFL (the classical 4%); that figure, however, was measured under closed, pre-mixed, static conditions. For the open, dynamic inhalation environment, the empirical value reported in the literature is **10%**, which is the figure referenced in practice as the operating ceiling. The 66% / 100% output devices are recorded in the Japanese Consumer Affairs Agency accident-information database, and from these considerations are not recommended.

See also:

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