# Pilot study of H₂ therapy in Parkinson's disease: a randomized double-blind placebo-controlled trial.
> パーキンソン病に対する水素水摂取の有効性：無作為化二重盲検プラセボ対照パイロット試験


## Abstract

Oxidative stress is implicated in Parkinson's disease (PD) progression, and molecular hydrogen has demonstrated antioxidant properties in preclinical models. This randomized, double-blind, placebo-controlled pilot study enrolled 17 Japanese PD patients receiving levodopa, who consumed either 1,000 mL/day of hydrogen-rich water or placebo water over 48 weeks. The primary endpoint was change in total Unified Parkinson's Disease Rating Scale (UPDRS) score. The hydrogen-rich water group (n=9) showed a median UPDRS improvement of −1.0 (mean −5.7 ± 8.4), while the placebo group (n=8) showed a median worsening of 4.5 (mean 4.1 ± 9.2). The between-group difference reached statistical significance (P<0.05) despite the small sample size and limited duration. No safety concerns were identified.

### Mechanism

Molecular hydrogen is proposed to selectively neutralize reactive oxygen species, particularly hydroxyl radicals, thereby reducing the oxidative stress implicated in Parkinson's disease pathology.

## Bibliographic

- **Authors**: Yoritaka A, Takanashi M, Hirayama M, Nakahara T, Ohta S, Hattori N
- **Journal**: Mov Disord
- **Year**: 2013
- **PMID**: [23400965](https://pubmed.ncbi.nlm.nih.gov/23400965/)
- **DOI**: [10.1002/mds.25375](https://doi.org/10.1002/mds.25375)
- **Study type**: human randomized controlled trial
- **Delivery route**: hydrogen-rich water
- **Effect reported**: positive

## Delivery context

Hydrogen-rich water is a low-risk delivery route, but the achievable systemic hydrogen dose is bounded. For clinical applications, inhalation is the most efficient route; inhalation, however, carries explosion risk, and concentration matters (empirical LFL of 10% applies to inhalation environments; high-concentration devices are documented in the Consumer Affairs Agency accident database and are not recommended).

## Safety notes

Hydrogen-rich water is a low-risk delivery route, but the achievable systemic hydrogen dose is bounded. For clinical applications, inhalation is the most efficient route; inhalation, however, carries explosion risk, and concentration matters (empirical LFL of 10% applies to inhalation environments; 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 23400965. https://h2-papers.org/en/papers/23400965
> **Source**: PubMed PMID [23400965](https://pubmed.ncbi.nlm.nih.gov/23400965/)