Hydrogen Water Improves Blood Vessel Function in Healthy Adults
Peripheral endothelial function can be improved by daily consumption of water containing over 7 ppm of dissolved hydrogen: A randomized controlled trial
Research hubs: Cardiovascular System
- Evidence type
- Randomized controlled trial · Human study
- Authors
- Toru Ishibashi, Kosuke Kawamoto, Kasumi Matsuno, Genki Ishihara, Takamichi Baba, Nobuaki Komori
- Journal
- PLoS One
- Year
- 2020
- PMID
- 32470022
- Study Type
- Human
- Participants
- 68
- Delivery
- Water (Dissolved)
- Dose
- 500 mL of water containing 7 ppm H2 (3.5 mg H2) daily for 14 days
- H₂ concentration
- 7 ppm
- Duration
- 2 weeks
- Funding
- No external funding declared
- Conflicts of interest
- None declared
- Outcome
- Positive
- Peer Reviewed
- Yes
- Cited by
- 16 (OpenAlex, as of November 2026)
- Country
- Japan
TL;DR
Drinking water with high levels of molecular hydrogen (H2) can improve the health of small blood vessels in the fingers, potentially benefiting heart health.
Key Finding
Drinking water containing 7 ppm of dissolved hydrogen daily for two weeks improved peripheral blood vessel function by 25.4% compared to placebo, as measured by a test of vascular responsiveness.
Summary
This study tested whether drinking water with high levels of dissolved hydrogen (a colorless gas) could improve how well blood vessels function in healthy people. Sixty-eight volunteers drank either regular water or water containing hydrogen for two weeks, and researchers measured blood vessel flexibility in their fingers using a special device. The group drinking hydrogen-enriched water showed better blood vessel function compared to the placebo group.
Practical Takeaway
This small human study suggests that hydrogen-enriched water may support blood vessel health in healthy people, though the practical significance of a 25% improvement in this specific measurement is unclear. The study was short-term (2 weeks) and involved only healthy volunteers, so it's unknown whether benefits would extend to people with existing cardiovascular conditions or persist with longer use. More research is needed before making any health decisions based on these results.
Abstract (excerpt)
Background: Measurement of the reactive hyperemia index (RHI) using peripheral arterial tonometry (PAT) has shown benefits in the evaluation of vascular endothelial function and prediction of cardiovascular disease prognosis. Thus, it is important to examine the factors that promote the RHI…