I was recently asked about hydrogen water and had to admit that I knew nothing about it. So today’s post is result of what I was able to find.
The key references for today’s post are:
- LeBaron, Tyler W., Randy Sharpe, and Kinji Ohno. “Electrolyzed–reduced water: Review ii: Safety concerns and effectiveness as a source of hydrogen water.” International Journal of Molecular Sciences 23.23 (2022): 14508.
- Nakayama, Masaaki, Shigeru Kabayama, and Mariko Miyazaki. “Application of Electrolyzed Hydrogen Water for Management of Chronic Kidney Disease and Dialysis Treatment—Perspective View.” Antioxidants 13.1 (2024): 90.
What Is Hydrogen Water?
Hydrogen water contains dissolved molecular hydrogen gas (H₂). When produced using an electrolyzing device, it typically becomes alkaline due to increased hydroxide (OH⁻) ions. These waters can have a very high pH— between 9-11.5.
Other names:
- electrolyzed reduced water (ERW)
- alkaline ionized water
Hydrogen water is not the same as mineral water (which you can learn more about here).
What Are the Proposed Benefits?
Some research suggests that hydrogen waters may:
- inhibit tumor growth
- protect the liver from toxins
- improve lipid metabolism
These effects appear related to the oxidation–reduction potential (ORP) created by dissolved hydrogen gas. Importantly, when ORP is removed, these benefits are not observed—suggesting the effect is specific to hydrogen, not alkalinity.
Potential Benefits of Hydrogen Water for Kidney Health
Because hydrogen water has antioxidant properties, some researchers have proposed that it may offer potential kidney-related benefits. In experimental rat models, drinking hydrogen-rich water has been shown to suppress kidney damage associated with hypertension, suggesting a protective effect against oxidative stress–mediated injury. There have been no intervention studies in patients with CKD using hydrogen water.
There is also emerging research in the dialysis population. In Japan, it is estimated that 30 facilities (over 3000 patients) receive dialysis using hydrogen-enriched dialysate. It has been reported that this has been associated with reduced markers of systemic oxidative stress, blood pressure, anti-hypertensive medications, fatigue and pruritus.
Reduction of oxidative stress could theoretically help lower cardiovascular and other major complications. In one prospective observational study, it was reported that the hydrogen water dialysis group vs the conventional group at a 41% lower hazard ration for total deaths, new stroke, CVD and lower limb amputation after a 5 year observation period. Future studies are looking to determine the ideal H2 concentrations and explore novel devices to hydrogenate the water.
Safety Concerns With Hydrogen or Alkaline Water
For the most part hydrogen water is considered safe. However, if hydrogen water also has a very high pH level, there are potential concerns:
1. Excessively high pH
Most hydrogen waters have a pH above 9, and some reach 10–11.5.
The recommended pH for drinking water is ≤ 8.5. Long-term intake of very alkaline water may contribute to:
- ventricular tachycardia
- electrolyte abnormalities
- impaired growth (reported in animal studies)
- dull or patchy fur in rat models
2. Stomach acid neutralization
Drinking 1 L of alkaline water at pH >10 can neutralize several hundred millilitres of stomach acid. This may impair:
- vitamin and mineral absorption
- digestion
- protection against pathogenic bacteria
People using PPIs or with partial gastrectomies may be at greater risk.
3. Metal or electrode degradation of the machine
Alkalizing devices may degrade over time, releasing nanoparticles or metals into the water—especially if:
- electrodes are used at high settings
- water is naturally alkaline
- limescale accumulates
This contributes to potential toxicity exposures. However, depending on the technique used to hydrogenate the water then this may be mitigated.
Does Alkaline Water Affect Potassium?
Although alkaline water might theoretically cause hypokalemia (more about that here), several human reports document hyperkalemia instead.
Possible mechanisms include:
- increased gastric acid production activating the parietal H⁺/K⁺ ATPase
- metal toxicity from degraded electrodes altering potassium handling
More research is needed in this area.
How Does the Baseline Water Source Affect Ionizer Output?
Water with a higher natural mineral content responds more readily to alkalizing electrodes. However, these same minerals—especially calcium—accumulate as limescale, reducing the electrode’s ability to add hydrogen.
Limescale must be removed regularly to maintain device effectiveness.
Can you control the pH of your water using the settings on water ionizers?
Many of these devices have a settings feature that allows users to set the pH, however in many cases the settings determines how much alkalizing power to apply to water but doesn’t have a test mechanism to understand the starting pH. This can mean that for people who start with a more alkaline water, these devices may cause the pH to become significantly higher than the setting on the device.
Recommendations for People Who Choose to Use Hydrogen-Generating Electrodes
If patients decide to use an alkalizing or hydrogen-generating device, they should:
- Use water with the optimal mineral content
Check the manufacturer’s recommendations. - Remove limescale regularly
A weak acid (e.g., vinegar) often works. - Monitor flow rate of the device
Device settings that use a low flow may lead to excessively high pH levels (>9.8). - Measure pH frequently
Don’t rely on the machine settings—these usually control alkalizing power but do not test the water directly. - Use a high-quality pH meter
Test the water to ensure safe consumption levels.
Are There Other Ways to Add Hydrogen?
Yes. Other delivery methods include:
- hydrogen inhalation
- intravenous H₂
- eye drops
- hyperbaric hydrogen baths
- hydrogen-releasing capsules
Some newer devices can add hydrogen without altering pH, which may reduce alkaline-related risks—but metal leaching remains a possibility.
Key Take-Aways
1. Hydrogen water has potential antioxidant benefits, but the evidence is still early.
Some studies suggest it may reduce oxidative stress or protect against certain types of tissue damage, including in experimental kidney models and dialysis studies—but large, long-term trials are still needed.
2. Very alkaline hydrogen water raises safety concerns.
High-pH water (often >10) can neutralize stomach acid, impair nutrient absorption, alter electrolytes, and potentially expose users to metal contaminants from ionizer electrodes.
3. Home-device settings can be often misleading, and users should test the pH of the water directly.
Machine “pH settings” typically do not measure actual pH, and mineral content, flow rate, and limescale buildup can all drive the pH much higher than intended—making regular pH testing essential for safety.
