Hydrogen Water: Hype or Hero?

Hydrogen water is regular water infused with molecular hydrogen (H₂) gas. It is said to act as an antioxidant and reduce inflammation. Over the decade it has grown significantly in popularity. Bottled hydrogen water, in-home generators, and tablets now line many wellness shelves. As a result, hundreds of brands worldwide market it as a convenient way to potentially support recovery, energy, and overall well-being.

There has been an exponential rise in the amount of research on hydrogen water over the last several years. This post goes into some of the largest studies on hydrogen water to help determine if it is hype or if it is helpful. Most hydrogen-water studies to date are small and have very modest effects on health. However, they are predominantly funded by universities or government (around 60% of studies reviewed), which may add to their validity (compared to corporate research perhaps).  

Promising or Positive Research

Hydrogen Water and Long COVID

A new study explored whether drinking hydrogen-rich water (HRW) could help people dealing with Long COVID symptoms. Over 14 days, participants were given either HRW or a placebo. The results showed that HRW significantly reduced fatigue and improved walking distance, muscle strength, and sleep quality. Most outcomes improved by around 10-20% with HRW. It did not improve breathing difficulties or mental health symptoms like stress or anxiety (Tan 2024).

Hydrogen Water for PMS

A recent randomized controlled trial tested whether hydrogen-rich water (HRW) could ease premenstrual symptoms (PMS) and improve quality of life. Women drank HRW from day 16 of their cycle to day 2 of the next, over three cycles. Those in the HRW group had a 16.3% lower PMS scores compared to those drinking regular water (Aker 2024). In other words - the effect on symptoms was quite small and not overly noticeable. The study was also small - with just 65 patients enrolled.

Hydrogen Water and Vascular Health

A 2020 randomized controlled trial studied the effects of drinking hydrogen-rich water on blood vessel function in 68 healthy adults (Ishibashi et al. 2020). Participants drank 500 ml of water with 7 ppm of hydrogen or a placebo daily for two weeks. Those in the hydrogen group showed a 25% improvement in endothelial function, measured by reactive hyperemia index (RHI), suggesting that hydrogen water may support cardiovascular health by enhancing small artery function. However, since RHI is a lab-based measurement, its real-world clinical relevance and reliability remain uncertain. A more helpful marker might be how many heart attacks occurred in one group versus the other.

Hydrogen Water and GERD

A 2018 study evaluated the impact of electrolyzed reduced water (ERW), rich in molecular hydrogen, in 84 patients with heartburn, aka gastroesophageal reflux disease (GERD) (Franceschelli et al. 2018). Over three months, patients received either proton pump inhibitors (PPIs) with regular water or PPIs with ERW. Those who took ERW showed a 10% greater improvement in GERD symptoms. These results are modest considering studies on other natural therapies typically show around a 30% improvement in GERD symptoms.

Hydrogen Water and Cholesterol

This randomized, double-blind, placebo-controlled crossover study looked at the effects of hydrogen-rich water on lipid and glucose metabolism in 36 patients with type 2 diabetes or impaired glucose tolerance. Over 8 weeks, those who drank 900 mL/day of hydrogen-rich water showed around 5-15% reductions in different cholesterol-related markers (Kajiyama et al. 2008). This study was quite small with 36 patients. In comparison, adding avocado into the diet has been found to reduce cholesterol by 11.2% (Li Wang 2015).

Negative Research: Side Effects

These studies below found possible side effects of hydrogen rich water.

Hydrogen-Rich Water May Raise Eye Pressure in Healthy Individuals

A 2023 study examined how drinking hydrogen-rich water (HRW) affects intraocular pressure (IOP) in healthy people (Najmanová et al. 2023). In a double-blind, randomized crossover trial with 24 participants, each drank either 1260 ml of HRW or placebo water. Both caused IOP to rise, but HRW led to more clinically significant increases (58% vs. 25%). The study suggests HRW may pose a greater IOP risk, especially for people at risk of glaucoma.

Hydrogen Water and Liver Health

A 2019 pilot trial tested hydrogen-rich water (HRW) in 12 patients with mild-to-moderate non-alcoholic fatty liver disease (NAFLD) (Korovljev et al. 2019). Over 28 days, patients drank 1 liter of HRW or placebo daily. HRW did appear to significantly reduce liver fat and improve one liver enzyme by about 10% (AST). Liver enzymes are a marker of liver health. It is common to see many natural therapies decrease liver enzymes by 40 to 60% in many studies. So a 10% drop in one liver enzyme is not overly impressive.

However, there was a weak trend towards increased insulin levels after HRW. This may not be good because high insulin levels signal your body to store fat and can cause cells to become insulin resistant. Over time, this leads to higher blood sugar, increasing risk of type 2 diabetes, weight gain, and heart disease. Importantly however studies on hydrogen in the context of diabetes often find benefit rather than harm with regards to blood sugar and insulin. So this study’s findings are not necessarily representative of the overall research.

They also found a trend towards increased levels of the hormone called ghrelin. There was a 96.1% increase versus a 34.7% increase in the placebo group. Ghrelin signals hunger; high levels can be beneficial if you need to gain weight or restore appetite, but problematic if you’re dieting, making weight loss harder. Chronic high ghrelin may disrupt sleep and metabolism. Balanced ghrelin (rising before meals, falling after) supports healthy hunger cues, mood, and growth hormone.

Neutral Research

Hydrogen Water and Aging

This study showed some promising results, but they only looked at lab measurements instead of real-world outcomes that matter to patients, like how they felt or how long they lived.

A 2021 pilot trial studied the effects of drinking hydrogen-rich water (HRW) over six months in adults aged 70 and older (Zanini et al. 2021). Forty participants drank either HRW or control water daily. HRW significantly preserved telomere length and increased TET2 expression, a DNA methylation marker. It also improved certain brain metabolites and physical performance (chair stand test). However, the study did not measure long-term outcomes like lifespan, making it unclear if these biological changes lead to actual improvements in how long or how well people live.

Hydrogen Water and Hepatitis

A 2013 study explored the effects of hydrogen-rich water (HRW) on patients with chronic hepatitis B (CHB). Sixty CHB patients were divided into two groups: one received standard treatment, and the other received standard treatment plus HRW (1200–1800 mL/day) for six weeks. HRW significantly reduced oxidative stress compared to the control group. Liver function and viral load (HBV DNA) improved in both groups, but differences between them were not statistically significant (Xia et al. 2013).

Hydrogen Water and Painful Bladder Syndrome

This randomized, double-blind, placebo-controlled trial tested hydrogen-rich water (HRW) in patients with interstitial cystitis/painful bladder syndrome (IC/PBS). Over 8 weeks, 30 patients received either HRW or placebo water. Both groups showed reduced bladder pain, but there was no significant difference in symptom improvement between them. Only 11% of patients had a notable benefit from HRW, suggesting limited effectiveness for IC/PBS treatment (Matsumoto et al. 2013).

Hydrogen Water and Parkinson’s Symptoms

A 2018 multicenter randomized controlled trial tested hydrogen-rich water (HRW) in people with Parkinson’s disease over 72 weeks (Yoritaka et al. 2018). Participants drank 1 liter of HRW or placebo daily. The study found no significant improvement in symptoms, including UPDRS scores, quality of life, or disease stage. While HRW was safe, it did not show therapeutic benefit in this long-term trial.

A 2021 pilot study tested the combined effects of hydrogen-rich water (HRW) and photobiomodulation (PBM) therapy in 18 people with Parkinson’s disease (Hong et al. 2021). Participants received daily PBM + HRW therapy for two weeks. Their symptoms, measured by the Unified Parkinson Disease Rating Scale (UPDRS), actually showed significant improvement within the first week in this trial and remained better than baseline after stopping therapy. However, there was no comparison group in this study, so this study could not determine whether drinking regular water in comparison to hydrogen water would have equivalent benefit. The study also did not give the exact numbers for improvement so size of benefit was difficult to assess. The treatment appears safe and potentially beneficial, but larger trials are needed.

Hydrogen Water and Exercise

The research on hydrogen water and exercise is overall mixed.

Exercise: Studies Showing No Impact

A 2022 randomized controlled study tested whether drinking hydrogen-rich water (HRW) before exercise could improve running performance in trained athletes (Valenta et al. 2022). Twenty-four male runners drank 1260 ml of HRW or placebo before running to exhaustion at their maximal aerobic speed. Results showed no significant difference in time to exhaustion, heart rate, oxygen uptake, or blood lactate levels. The study concluded that HRW did not enhance running performance.

A 2020 randomized controlled trial tested whether hydrogen-rich water (HRW) boosts treadmill running performance in 14 endurance-trained male athletes (Ooi et al. 2020). Participants drank two 290 ml doses of HRW or placebo before submaximal and maximal running tests. Results showed no significant differences in time to exhaustion, oxygen uptake, heart rate, or perceived exertion. The study concluded that small doses of HRW did not enhance endurance performance in trained runners.

Exercise: Studies Showing Benefit

A 2019 double-blind study tested hydrogen-rich water (HRW) during exercise (Mikami et al. 2019). They found a 8% greater increase in VO₂max in those using HRW compared to placebo. The VO₂max is how much oxygen your body can take in and use when you’re really pushing yourself—basically a number that shows how fit your heart and lungs are. It’s measured in milliliters of oxygen per minute. An 8% increase is reasonable, as many other natural therapies for increasing VO₂max show about the same or a slightly lower increase. For example, research on beets has found about a 5% increase in VO₂max (Fernandes de Castro et al. 2025).

A 2018 study investigated whether hydrogen-rich water (HRW) could enhance sprint performance during prolonged cycling in eight trained male cyclists (Da Ponte et al. 2018). The study found HRW helped prevent a 12% decrease in peak power output compared to drinking regular water in late sprints. A 12% difference is about the same change in power we see with other natural therapies. So while the effect is statistically valid, the effect size is modest and the sample size is small. This makes it difficult to conclude if HRW makes a practical difference for most individuals with possibly the exception of professional cyclists.

Conclusion

Hydrogen water has some promising research available however overall studies are small and most studies report small improvements. Similar or better impacts can be seen with many common foods, lifestyle changes or other natural therapies. Some possible benefits may exist for boosting exercise performance and reducing PMS symptoms. However, one study found a possible risk of raised eye pressure - which has the potential to harm the eyes in the long term.  Many sources state side effects are limited and the review of the research here did not find any other side effects. Much of the research measures lab markers rather than concrete objective measures like longevity, number of heart attacks or strokes. If someone is looking for a small boost, hydrogen water may provide a slight benefit to energy levels. In summary, hydrogen water appears relatively safe and may offer slight benefits, but its true value remains uncertain until larger studies confirm more meaningful effects.

Hydrogen Water