# Status quo, challenges and future directions of hydrogen medicine.
> 水素医学の現状・課題・将来展望：生物学的機序・代謝挙動・デリバリー技術の包括的レビュー


## Abstract

Molecular hydrogen (H₂) possesses several distinctive properties—broad-spectrum anti-inflammatory activity, favorable biosafety profile, and high tissue permeability—that underpin its potential in diseases driven by inflammation and oxidative stress. This review synthesizes current knowledge across three domains: (1) biological mechanisms, including the identification of H₂ molecular targets and the challenge of accounting for its diverse cellular effects; (2) metabolic behavior, encompassing detection methodologies and experimental evidence—obtained with a newly developed H₂ molecular bioprobe—demonstrating H₂'s capacity to cross biological barriers; and (3) delivery strategies, tracing the evolution from passive H₂ carrier materials to hydrolytic and catalytic H₂-generating systems designed to improve efficacy. The review concludes by delineating priority directions for future research in hydrogen medicine.

### Mechanism

H₂ is proposed to selectively scavenge highly reactive oxygen species—including hydroxyl radicals and peroxynitrite—through interaction with specific molecular targets, thereby broadly suppressing inflammatory signaling cascades.

## Bibliographic

- **Authors**: Chen SL, Zeng L, He Q
- **Journal**: Fundam Res
- **Year**: 2026
- **PMID**: [41971791](https://pubmed.ncbi.nlm.nih.gov/41971791/)
- **DOI**: [10.1016/j.fmre.2025.06.014](https://doi.org/10.1016/j.fmre.2025.06.014)
- **PMC**: [PMC13069841](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13069841/)
- **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 41971791. https://h2-papers.org/en/papers/41971791
> **Source**: PubMed PMID [41971791](https://pubmed.ncbi.nlm.nih.gov/41971791/)