# Molecular Hydrogen in the Treatment of Respiratory Diseases.
> 分子状水素と呼吸器疾患：過去20年間の研究知見のレビュー


## Abstract

This review consolidates findings from approximately twenty years of research on molecular hydrogen (H2) in the context of respiratory conditions. H2, once regarded as a biologically inert gas, has emerged as an agent with antioxidant, anti-inflammatory, and antiapoptotic properties. The scope of the review encompasses allergic conditions, asthma, chronic obstructive pulmonary disease, pulmonary fibrosis, lung injury of diverse etiologies, respiratory tract infections, and lung cancer. The fundamental molecular mechanisms underlying H2 biological activity in the respiratory system are also described, providing a mechanistic framework for interpreting the accumulated experimental and clinical evidence across these disease categories.

### Mechanism

H2 selectively scavenges highly reactive oxygen species, including hydroxyl radicals and peroxynitrite, while suppressing pro-inflammatory signaling cascades and apoptotic pathways, thereby exerting cytoprotective effects in respiratory tissues.

## Bibliographic

- **Authors**: Zajac D, Jampolska M, Wojciechowski P
- **Journal**: Int J Mol Sci
- **Year**: 2025 (2025-04-26)
- **PMID**: [40362357](https://pubmed.ncbi.nlm.nih.gov/40362357/)
- **DOI**: [10.3390/ijms26094116](https://doi.org/10.3390/ijms26094116)
- **PMC**: [PMC12072089](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12072089/)
- **Study type**: review
- **Delivery route**: mixed routes
- **Effect reported**: not assessed

## Delivery context

This study combines multiple delivery routes. As a general principle, the most efficient route for routine hydrogen intake is inhalation. Inhalation carries explosion risk (empirical LFL of 10%; high-concentration devices are documented in the Consumer Affairs Agency accident database and are not recommended).

## Safety notes

This study combines multiple delivery routes. As a general principle, the most efficient route for routine hydrogen intake is inhalation. Inhalation carries explosion risk (empirical LFL of 10%; high-concentration devices are documented in the Consumer Affairs Agency accident database and are not recommended).

See also:
- [Inhalation concentration and LFL / UFL](https://h2-papers.org/en/safety-notes/inhalation-concentration)
- [Consumer Affairs Agency accident cases](https://h2-papers.org/en/safety-notes/accident-cases)
- [Inhalation safety threshold lineage](https://h2-papers.org/en/safety-notes/lineage)

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> **Cite as**: H2 Papers — PMID 40362357. https://h2-papers.org/en/papers/40362357
> **Source**: PubMed PMID [40362357](https://pubmed.ncbi.nlm.nih.gov/40362357/)