About this database

H2 Papers is a structured database of PubMed molecular-hydrogen (H₂) medical literature, served in Japanese and English. Each paper page carries delivery-method-aware safety notes (inhalation / hydrogen-rich water / injection / bath / topical) inline.

The site is organized so a reader can see a paper alongside the background it depends on — how delivery routes differ, which concentration ranges matter, what accident history has been recorded — without flipping between separate pages. It is meant as a readable entry point to the primary literature for researchers, clinicians, and ordinary readers gathering background on hydrogen-related questions.

1. Collection: Papers whose title or abstract mention molecular hydrogen (or hydrogen-rich water, H₂ inhalation, etc.) together with medical-context terms are pulled weekly from the NCBI public API.
2. Organizing: For each paper we record study type (RCT, observational, animal, etc.), delivery route, the effect reported, hydrogen concentration where stated, related topics, and a short summary of the proposed mechanism.
3. Japanese version: Japanese abstracts are written independently rather than translated word-for-word — kept faithful to the paper's content while staying outside the copyright of the original abstract.

Total papers

1,168

Inhalation

159

Hydrogen-rich water

321

Injection

73

Safety lineage papers

1

Year range

1974–2026

• We stay within the range of claims the original authors made. Physiological mechanisms are written in plain assertive language for readability, but disease-specific effects are expressed as "has been reported" or "has been observed", staying close to the source.
• Commercial language, recommendations of particular products or treatments, and wording that guarantees efficacy are avoided. Names and titles other than the original authors are not surfaced.
• Safety-relevant context (concentration ranges by delivery route, recorded incidents) is treated as prerequisite reading and is shown alongside the related paper pages.
• Retracted papers are excluded from the database. Papers from journals that may be predatory are flagged on the page itself.

• Structured layer (Japanese abstracts, mechanism summaries, tag taxonomy): CC BY 4.0
• Source abstracts and bibliographic data: NLM / journal-owned. We reconstruct rather than reproduce.
• Cite as: via H2 Papers — PMID {pmid}. https://h2-papers.org/papers/{pmid}

Newly published papers are pulled in every Monday (around noon, Japan time). Safety-notes pages get a new revision when the content changes substantively, and earlier revisions remain accessible.