Randomized, double-blind, multicenter trial of hydrogen water for Parkinson's disease
Yoritaka A, Ohtsuka C, Maeda T, Hirayama M, Abe T, Watanabe H, Saiki H, Oyama G, Fukae J, Shimo Y, Hatano T, Kawajiri S, Okuma Y, Machida Y, Miwa H, Suzuki C, Kazama A, Tomiyama M, Kihara T, Hirasawa M, Shimura H, Oda E, Ito M, Ohno K, Hattori N. · Movement disorders : official journal of the Movement Disorder Society. 2018;33(9):1505–1507.
Study at a glance
In a 14-hospital trial, 178 people with Parkinson’s disease were assigned hydrogen-rich water or placebo water for 72 weeks. Symptoms did not improve more with hydrogen water. Only 135 participants contributed to the week 72 table, and detailed supplementary safety data were unavailable for this review.
Human
Adults with Parkinson’s disease, modified Hoehn and Yahr stages 1–4 in the on-phase and stable antiparkinson medication for 8 weeks. Participants with MMSE below 25, dysphagia or serious concurrent illness were excluded.
Hydrogen-rich drinking water, 1000 mL/day for 72 weeks, was supplied as two 500 mL bottles; the protocol specified drinking within 3 hours of opening. Follow-up continued for 8 weeks after treatment. · Protocol: 5 mM dissolved H₂. Delivered intervention concentration is not independently resolved from the final report; its 0.16 ± 0.16 ppm wording is ambiguous.
72 weeks of assigned water, followed by 8 weeks after treatment.
Mean change +1.6 ± 14.0 points with H2-water versus +0.8 ± 9.6 with placebo; no significant between-group difference. Higher scores indicate worse symptoms. No sustained benefit in UPDRS components, Hoehn and Yahr stage, PDQ-39 quality-of-life scores or withdrawal for disease progression. Isolated secondary time-point signals: UPDRS II week 8 favors H2 (P=.010); stigma at week 24 favors placebo (P=.035). These do not overturn the primary null result.
Only 135 of 178 randomized participants appear in the week-72 table. Selected Parkinson’s disease stages, no off-phase UPDRS assessment, little progression in either group and a brief final report limit interpretation. Detailed supplementary harms and attrition files were unavailable. Sex counts, primary-result P values and concentration wording differ within or between the reports; no definitive sex breakdown or single resolved primary P value is asserted.
What kind of evidence is this?
Human
Randomized, double-blind, placebo-controlled, parallel-group multicenter trial; planned 1:1 allocation across 14 Japanese hospitals.
Parkinson’s disease
H₂-rich water
Information not yet classified
Some editorial classification fields are still pending. The source-reported outcomes and result are shown below; Hydrogenology does not infer a positive or negative signal from prose automatically.
Methods
Adults with Parkinson’s disease, modified Hoehn and Yahr stages 1–4 in the on-phase and stable antiparkinson medication for 8 weeks. Participants with MMSE below 25, dysphagia or serious concurrent illness were excluded.
178 randomized. Randomized arm sizes were not verified from the final letter; planned 1:1 allocation is not an observed 89/89 count. At week 72, the table includes 69 hydrogen-water and 66 placebo participants (135 total); sample sizes differ at other visits. The table is labelled modified intent-to-treat.
72 weeks of assigned water, followed by 8 weeks after treatment.
Hydrogen-rich drinking water, 1000 mL/day for 72 weeks, was supplied as two 500 mL bottles; the protocol specified drinking within 3 hours of opening. Follow-up continued for 8 weeks after treatment.
Molecular hydrogen dissolved in drinking water.
Protocol: 5 mM dissolved H₂. Delivered intervention concentration is not independently resolved from the final report; its 0.16 ± 0.16 ppm wording is ambiguous.
1000 mL/day placebo water; protocol describes nitrogen-saturated water in matching bottles.
Outcomes and reported result
Change in total Unified Parkinson’s Disease Rating Scale (UPDRS) from baseline to week 72.
Mean change +1.6 ± 14.0 points with H2-water versus +0.8 ± 9.6 with placebo; no significant between-group difference. Higher scores indicate worse symptoms. No sustained benefit in UPDRS components, Hoehn and Yahr stage, PDQ-39 quality-of-life scores or withdrawal for disease progression. Isolated secondary time-point signals: UPDRS II week 8 favors H2 (P=.010); stigma at week 24 favors placebo (P=.035). These do not overturn the primary null result.
The complete three-page primary results letter, protocol and protocol erratum were reviewed. Supplementary flow, baseline and discontinuation/harms files were unavailable; their contents have not been verified.
Adverse events were among the reported reasons for stopping. Supplementary event and withdrawal counts were unavailable; the authors’ safety description cannot establish that there were no adverse events or that use is generally safe.
A reported association, difference or mechanism is not automatically a clinical benefit.
Limitations and applicability
Only 135 of 178 randomized participants appear in the week-72 table. Selected Parkinson’s disease stages, no off-phase UPDRS assessment, little progression in either group and a brief final report limit interpretation. Detailed supplementary harms and attrition files were unavailable. Sex counts, primary-result P values and concentration wording differ within or between the reports; no definitive sex breakdown or single resolved primary P value is asserted.
Adults with Parkinson’s disease, modified Hoehn and Yahr stages 1–4 in the on-phase and stable antiparkinson medication for 8 weeks. Participants with MMSE below 25, dysphagia or serious concurrent illness were excluded. Findings apply only to the studied design and exposure; no treatment or device recommendation.
JSPS KAKENHI 15K09360. MiZ Co., Ltd. and Ecomointernational supplied Suisosui 7.0 and placebo water.
The final letter states no relevant conflicts or financial disclosures. The protocol includes professional advisory and consultancy disclosures. The companies’ provision of hydrogen and placebo water is declared separately under funding and support.
Structured limitations review — preliminary, AI-assisted
Formal outcome-level risk-of-bias assessment not completed
The editorial review covers the complete primary results letter, protocol and protocol erratum. Attrition, inconsistent reporting and unavailable supplementary harms/withdrawal details limit interpretation. The null primary result is retained; no independent clinical or statistical appraisal is claimed.
Randomized, double-blind multicentre design reported. · 135 of 178 participants represented at week 72; supplementary attrition detail unavailable. · Exact primary P values, concentration wording and sex counts are inconsistent. · No independent outcome-level protocol/registry-history assessment completed.
No single-study GRADE certainty rating is assigned. Read how records and evidence assessments are prepared.
Sources and record status
PMID: 30207619 · DOI: 10.1002/mds.27472
Complete three-page primary results letter, uploaded by corresponding author Asako Yoritaka to ResearchGate; matching journal layout, DOI and pagination.
AI-assisted editorial review of the available main full text, 29 October 2026. The source version and access limitations are stated in this record. No independent clinical or statistical assessment has been performed.
All three article pages 1505–1507 Randomization, registration and sample paragraph Table 1 at page 1506: sample sizes at each follow-up, UPDRS and quality-of-life results Discussion, limitations, concentration paragraph, acknowledgments and disclosures
AI-assisted editorial review of the available main full text, 29 October 2026. Complete three-page primary results letter, uploaded by corresponding author Asako Yoritaka to ResearchGate; matching journal layout, DOI and pagination. The protocol and its published erratum were also reviewed; supplementary harms and attrition files were unavailable.
UMIN000010014. The 2016 protocol (PMID 27176725) and its 2017 erratum describe the same 178-person trial as the primary results letter. They are companion sources from the same cohort, not independent outcome studies. This trial is distinct from the 2013 pilot (PMID 23400965) and the 2021 inhalation study (PMID 34319514).
29 October 2026
Help people check the facts before they buy.
Hydrogenology keeps 692 source-checked records accessible without advertising or product promotion.
Help us correct the recordReport a discrepancy
Send the exact difference between this page and the linked source. The study reference is attached automatically.