Molecular hydrogen and the brain: the Nature Medicine study that revolutionised oxidative stress

Why are we talking about hydrogen and the brain?

The brain is one of the organs most sensitive to oxidative stress – the “wear and tear” caused by excess free radicals. Conditions such as stroke, lack of oxygen, severe inflammation, and even accelerated ageing are strongly linked to this imbalance. PubMed

In 2007, a group of Japanese researchers published a study in Nature Medicine that surprised the scientific community: inhaling hydrogen gas (H₂) significantly reduced brain damage in a model of ischaemia in rats. Nature+1

The phrase that became famous was:

“The inhalation of H₂ gas markedly suppressed brain injury by buffering the effects of oxidative stress.” SciSpace

But what does this mean in practice? And what does this have to do with hydrogen-rich water and the way we drink water every day?

The Nature Medicine study in simple language

How was the study conducted?

Researchers led by Ikuroh Ohsawa used a well-known model in neurology:

  • Rats were subjected to cerebral ischaemia (temporary blockage of an artery in the brain) followed by reperfusion (restoration of blood flow).

  • This process causes intense oxidative stress and nerve cell death, similar to what happens in an ischaemic stroke. ResearchGate

During this process, some animals inhaled hydrogen gas in low concentrations (between 1% and 4% mixed with oxygen and nitrous oxide). Others did not receive hydrogen and served as a control group.

What did the scientists discover?

The results were impressive:

  • The rats that inhaled H₂ had less damaged brain tissue (less “cerebral infarction”). ResearchGate

  • There was also less inflammation and cell death in the affected areas.

  • Hydrogen did not interfere with other radicals important for normal cell signalling, focusing mainly on the most destructive radicals. ResearchGate+1

This led to the conclusion that H₂ acts as a selective antioxidant, capable of reducing some of the most toxic radicals without completely “shutting down” the body’s normal mechanisms.

What makes molecular hydrogen so special?

Molecular hydrogen (H₂) is the smallest molecule in the universe. This gives it several unique advantages: ResearchGate+1

  1. It diffuses very quickly throughout the body, crossing cell membranes, mitochondria and even the blood-brain barrier (the brain’s ‘safety barrier’).

  2. It is selective: it reacts mainly with the most toxic radicals, such as the hydroxyl radical (•OH) and peroxynitrite (ONOO⁻), which are highly destructive.

  3. It does not completely block all free radicals, allowing the body to maintain its normal defence and signalling functions, unlike some antioxidants in high doses.

  4. It has been used for decades in contexts such as deep-sea diving, showing a good safety profile at low concentrations. ResearchGate

This combination – efficacy + selectivity + safety – is what makes molecular hydrogen such an interesting antioxidant for research.

Why was this study so important?

Since the publication of the article in Nature Medicine in 2007, the work of Ohsawa and colleagues has been cited thousands of times and is considered the starting point of so-called “hydrogen medicine”. PubMed+1

From there, dozens of other preclinical and clinical studies have emerged exploring H₂ in different contexts:

  • Cardiovascular and metabolic diseases

  • Ischemia/reperfusion injury (heart, liver, kidneys)

  • Chronic inflammatory and oxidative processes

  • Recovery after intense physical exercise ScienceDirect

It is important to note:

The original study was conducted on animals in a very specific context (experimental stroke model). It is not a “miracle cure” nor does it replace medical treatments. However, it has opened up a new avenue for thinking about antioxidant protection – one that is smarter, more selective and potentially safer.

Inhaling gas vs. drinking hydrogen-rich water

In the Nature Medicine study, hydrogen was administered in the form of inhaled gas. However, other studies have shown that H₂ can be administered in various ways: ResearchGate+1

  • Inhalation of H₂ gas

  • Hydrogen-enriched saline solution (H₂-saline)

  • Hydrogen-rich drinking water, obtained by dissolving the gas or by electrolysis (as in many high-performance water ionisers)

Hydrogen-rich water does not provide doses as high as inhalation in a hospital setting, but it has a major advantage:

it can be used practically and daily as a complement to a healthy lifestyle.

State-of-the-art water ionisers can produce alkaline and antioxidant water with dissolved H₂, ready for daily consumption.

If you would like to explore this topic further, please visit:

What does this mean for you in practice?

1. Oxidative stress is real – and should be taken seriously

The study reinforces the idea that excessive oxidative stress profoundly damages the brain and other organs. Reducing this oxidative burden is a central strategy for protecting long-term health.

2. Molecular hydrogen is a promising ally

Results in animals, and subsequent studies in humans, indicate that H₂ can help modulate oxidative and inflammatory stress, with a favourable safety profile. Further research is still needed, but the scientific basis is solid and growing rapidly. ScienceDirect

3. The water you drink may be more than ‘just’ water

When you drink hydrogen-rich water, you are not just hydrating yourself. You are providing your body with an additional source of H₂, which can act selectively on the most aggressive radicals.

Integrating this type of water into your daily routine, combined with:

  • Anti-inflammatory diet

  • Restful sleep

  • Stress management

  • Regular physical activity

can be a smart way to support your body in the fight against premature ageing and cellular wear and tear.

Three steps to experience the benefits of H₂ in your daily life

  1. Get in-depth information
    Explore the contents of our blog and learn more about what science already knows about ionised water, molecular hydrogen and health.

  2. Watch a live demonstration
    Schedule a demonstration (in person or online) and see for yourself how H₂-rich water is produced and how it differs from tap or bottled water.

  3. Choose the right equipment for your family
    Discover the available ioniser models, with different investment options, features and hydrogen production levels, to integrate superior quality water into your daily routine.

Frequently asked questions

Does this study prove that hydrogen ‘cures’ stroke or other diseases?

No. The study shows that, in rats, H₂ inhalation reduced the extent of brain damage in an ischaemia/reperfusion model. This is a very promising result, but it does not replace medical treatment or authorise promises of a cure.

Is drinking hydrogen-rich water the same as inhaling H₂ gas?

It is not exactly the same – the concentrations and form of administration are different. Inhalation can achieve higher levels of H₂ in a hospital setting; hydrogen-rich water offers lower doses, but repeated throughout the day, in a practical and convenient way.

Is it safe to consume molecular hydrogen?

At the concentrations used in clinical studies and in drinking water, H₂ has shown an excellent safety profile. Gas concentrations below 4% in the air pose no risk of explosion, and the body easily excretes excess H₂ through respiration. ResearchGate

Key references

  • Ohsawa, I. et al. (2007). Hydrogen acts as a therapeutic antioxidant by selectively reducing cytotoxic oxygen radicals. Nature Medicine, 13(6), 688–694. DOI: 10.1038/nm1577. Available at: Nature+1 and PubMed.

  • Ohta, S. (2012). Molecular hydrogen is a novel antioxidant to efficiently reduce oxidative stress with potential for the improvement of mitochondrial diseases. Pharmacology & Therapeutics. ScienceDirect