# Potential ghrelin-mediated benefits and risks of hydrogen water.
> 水素水摂取によるグレリン介在性の生理的効果と潜在的リスクに関する仮説的考察


## Abstract

Molecular hydrogen scavenges hydroxyl radicals and reduces peroxynitrite toxicity, providing antioxidant potential. A mouse study found that oral hydrogen-rich water (HW) elevates gastric ghrelin production, and this ghrelin was identified as a mediator of HW's protective effects in a Parkinson's disease model. Ghrelin, beyond its roles as an appetite stimulant and growth hormone secretagogue, exerts neuroprotective, cognitive-enhancing, vascular, anti-inflammatory, and hepatoprotective effects via the widely expressed GHS-R1a receptor. The hypothesis that ghrelin mediates many of the benefits observed with HW in experimental settings is explored. However, upregulation of GH-IGF-I signaling through sustained ghrelin elevation raises potential concerns about long-term cancer risk. The author proposes that the effect of HW ingestion on ghrelin levels in humans requires direct investigation to clarify both the promise and the risks of this approach.

### Mechanism

Oral hydrogen-rich water is proposed to stimulate gastric ghrelin secretion; ghrelin then acts via GHS-R1a receptors to confer neuroprotective, anti-inflammatory, and hepatoprotective effects, while concurrent GH-IGF-I pathway activation may carry long-term cancer risk implications.

## Bibliographic

- **Authors**: McCarty MF
- **Journal**: Med Hypotheses
- **Year**: 2015
- **PMID**: [25649854](https://pubmed.ncbi.nlm.nih.gov/25649854/)
- **DOI**: [10.1016/j.mehy.2015.01.018](https://doi.org/10.1016/j.mehy.2015.01.018)
- **Study type**: other
- **Delivery route**: hydrogen-rich water
- **Effect reported**: not assessed

## 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 25649854. https://h2-papers.org/en/papers/25649854
> **Source**: PubMed PMID [25649854](https://pubmed.ncbi.nlm.nih.gov/25649854/)