Molecular Hydrogen and brain health

Molecular Hydrogen

  • Food & Drink
  • Updated March 14, 2019

Molecular hydrogen (H2) is a gas that is found in trace amounts in the air (0.00005%). It can act as an antioxidant and is thought to protect cells from oxidative stress-related damage. Hydrogen can be inhaled as a gas at low concentrations (1-3%) or infused into water. A saturated solution of hydrogen contains 1.6 parts per million (ppm) hydrogen. In preclinical models, molecular hydrogen was most beneficial when used chronically as a preventative measure, before the onset of pathology. However, short-term clinical studies have failed to show clear cognitive benefits. Hydrogen therapy is generally considered safe.


A few small clinical trials have tested whether molecular hydrogen preserves cognitive function in populations at high risk for cognitive decline, in the form of hydrogen-rich water, hydrogen-rich saline infusions, or hydrogen gas inhalation. The inconsistent results may relate to the different sources and doses of hydrogen used in these studies.

Our search identified:

  • 6 clinical trials in populations at high risk for dementia (mild cognitive impairment, Parkinson's disease, and stroke)
  • 1 randomized clinical trial in healthy adults looking at effects on cognitive function
  • Numerous preclinical studies on possible mechanisms of action

Potential Benefit

Daily consumption of 600 mL of hydrogen-rich water, containing 0.8-1.2 ppm hydrogen, for one month did not improve cognitive function in healthy young adults [1].

Randomized clinical trials including patients with mild cognitive impairment and early stage Parkinson's disease also failed to show significant benefits in preventing cognitive decline. Daily consumption of 300 mL of hydrogen-rich water (1.2 ppm hydrogen) for a year did not improve overall scores on cognitive tests in people with mild cognitive impairment [2]. One small trial found that consumption of 1 L of hydrogen-rich water (1.6 ppm hydrogen) could slightly slow disease worsening in Parkinson's disease patients [3], but these findings were not replicated in a larger trial [4]. It is unclear whether the results were different because the studies used different formulations of hydrogen-rich water.

In one study, stroke patients treated with 3% hydrogen gas therapy had less severe neurological impairment [5]. The neuroprotection is thought to relate to a reduction in oxidative stress damage. Similar benefits were not seen with infusions of hydrogen-rich saline, as one small clinical trial reported only a marginally faster rate of recovery [6], while another study indicated there was no added benefit [7].

For APOE4 Carriers

In the trial of people with mild cognitive impairment, APOE4 carriers were the only subgroup to show benefits on cognitive tests in response to hydrogen-rich water consumption [2], but there is no evidence for clinically apparent benefit.

For Dementia Patients

Molecular hydrogen therapy has not been tested in patients with dementia. In preclinical models of Alzheimer's disease, hydrogen treatment reduced markers of oxidative stress and enhanced synaptic function, but did not reduce biological markers of Alzheimer's pathology (beta-amyloid and tau) [8].


Hydrogen-infused water has been granted Generally Recognized as Safe (GRAS) status by the FDA, which means that it is generally considered safe for consumption. In randomized clinical trials, molecular hydrogen intake was generally not associated with side effects, and animals consuming hydrogen-rich water throughout adulthood also did not show side effects [9][10]. The consumed hydrogen only lasts in the body about one hour [11]. Hydrogen gas is not flammable at concentrations lower than 4% [12], so hydrogen gas administered at 1-3% in a clinical setting is considered safe.

NOTE: This is not a comprehensive safety evaluation or complete list of potentially harmful drug interactions. It is important to discuss safety issues with your physician before taking any new supplement or medication.

How to Use

Hydrogen-infused water can be purchased in ready-to-drink aluminum pouches, or it can be produced at home by using hydrogen tablets, hydrogen sticks, a water ionizer, or a hydrogen infusion machine. Hydrogen-rich water is best consumed within an hour of opening, because the hydrogen gas is rapidly released back into the air [11]. However, these products can vary widely in the level of hydrogen, and there is no clinically validated level for optimal benefit, or research-based evidence that any level of hydrogen can reduce the risk for dementia.

Learn More

A scientific review on the potential of molecular hydrogen in preventing and treating diseases.


  1. Mizuno K, Sasaki AT, Ebisu K et al. (2018) Hydrogen-rich water for improvements of mood, anxiety, and autonomic nerve function in daily life. Medical gas research 7, 247-255.
  2. Nishimaki K, Asada T, Ohsawa I et al. (2018) Effects of Molecular Hydrogen Assessed by an Animal Model and a Randomized Clinical Study on Mild Cognitive Impairment. Current Alzheimer research 15, 482-492.
  3. Yoritaka A, Takanashi M, Hirayama M et al. (2013) Pilot study of H2 therapy in Parkinson's disease: A randomized double-blind placebo-controlled trial. Movement Disorders 28, 836-839.
  4. Yoritaka A, Ohtsuka C, Maeda T et al. (2018) Randomized, double-blind, multicenter trial of hydrogen water for Parkinson's disease. Movement Disorders 33, 1505-1507.
  5. Ono H, Nishijima Y, Ohta S et al. (2017) Hydrogen Gas Inhalation Treatment in Acute Cerebral Infarction: A Randomized Controlled Clinical Study on Safety and Neuroprotection. Journal of Stroke and Cerebrovascular Diseases 26, 2587-2594.
  6. Ono H, Nishijima Y, Adachi N et al. (2011) Improved brain MRI indices in the acute brain stem infarct sites treated with hydroxyl radical scavengers, Edaravone and hydrogen, as compared to Edaravone alone. A non-controlled study. Medical Gas Research 1, 12.
  7. Nagatani K, Nawashiro H, Takeuchi S et al. (2013) Safety of intravenous administration of hydrogen-enriched fluid in patients with acute cerebral ischemia: initial clinical studies. Medical gas research 3, 13-13.
  8. Hou C, Peng Y, Qin C et al. (2018) Hydrogen-rich water improves cognitive impairment gender-dependently in APP/PS1 mice without affecting Aβ clearance. Free Radical Research, 1-12.
  9. Gu Y, Huang C-S, Inoue T et al. (2010) Drinking hydrogen water ameliorated cognitive impairment in senescence-accelerated mice. Journal of clinical biochemistry and nutrition 46, 269-276.
  10. Tomofuji T, Kawabata Y, Kasuyama K et al. (2014) Effects of hydrogen-rich water on aging periodontal tissues in rats. Scientific reports 4, 5534-5534.
  11. Shimouchi A., Nose K., Shirai M. et al. (2012) Estimation of Molecular Hydrogen Consumption in the Human Whole Body After the Ingestion of Hydrogen-Rich Water. vol. 737, Oxygen Transport to Tissue XXXIII Advances in Experimental Medicine and Biology. New York, NY: Springer.
  12. Hydrogen. PubChem.