# Peripheral endothelial function can be improved by daily consumption of water containing over 7 ppm of dissolved hydrogen: A randomized controlled trial.
> 7ppm以上の水素水の継続摂取による末梢血管内皮機能の改善：ランダム化比較試験


## Abstract

This randomized controlled trial enrolled 68 healthy volunteers assigned equally to either a high-concentration hydrogen water group (7 ppm H2; 3.5 mg per 500 mL) or a nitrogen-water placebo group. Peripheral vascular endothelial function was assessed using the reactive hyperemia index (Ln_RHI) measured by peripheral arterial tonometry (PAT) at baseline, 1 hour, 24 hours after the first intake, and following 14 days of daily consumption. The hydrogen water group demonstrated a statistically significant 22.2% increase in Ln_RHI at 24 hours post-ingestion and a 25.4% increase after two weeks of daily intake, both significantly greater than placebo. These findings indicate that sustained consumption of high-concentration hydrogen water is associated with measurable improvements in small artery and arteriole endothelial function, with potential implications for cardiovascular health.

### Mechanism

Consumption of hydrogen-rich water at concentrations exceeding 7 ppm was associated with enhanced endothelial responsiveness in peripheral small arteries and arterioles, as reflected by increased Ln_RHI values. The mechanism is presumed to involve reduction of oxidative stress, thereby improving endothelial vasodilatory capacity.

## Bibliographic

- **Authors**: Ishibashi T, Kawamoto K, Matsuno K, Ishihara G, Baba T, Komori N
- **Journal**: PLoS One
- **Year**: 2020
- **PMID**: [32470022](https://pubmed.ncbi.nlm.nih.gov/32470022/)
- **DOI**: [10.1371/journal.pone.0233484](https://doi.org/10.1371/journal.pone.0233484)
- **PMC**: [PMC7259729](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7259729/)
- **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)

---

> **Cite as**: H2 Papers — PMID 32470022. https://h2-papers.org/en/papers/32470022
> **Source**: PubMed PMID [32470022](https://pubmed.ncbi.nlm.nih.gov/32470022/)