HYDROGEN WATER IS REGULAR WATER WITH DISSOLVED MOLECULAR HYDROGEN GAS
Hydrogen-rich water sounds more complicated than it actually is. It is ordinary drinking water containing additional molecular hydrogen gas, H₂, dissolved in the water.
The hydrogen gas does not become part of the H₂O molecule. It does not turn water into a new chemical compound. It is simply dissolved molecular hydrogen—similar in concept to dissolving carbon dioxide into water, except the gas is H₂.
What makes hydrogen water technically interesting is that H₂ is extremely small, neutral, nonpolar, poorly soluble in water, rapidly diffusible and easily lost from solution.
That means understanding hydrogen-rich water requires more than asking whether a machine makes bubbles.
We need to understand concentration, total H₂ dose, pressure, temperature, retention, measurement and the technology used to produce it.
We also need to know whether a hydrogen-water product actually delivers the performance its manufacturer claims.
That is why independent testing and product evaluation are an important part of the work we do at H2HUBB.
I originally wrote this article in 2017 as an introduction for people encountering hydrogen water for the first time. This 2026 update takes that foundation much further.
Originally published September 28, 2017. Updated August 27, 2026.
H2HUBB Takeaway
- Hydrogen water is ordinary water containing dissolved molecular hydrogen gas, H₂. The H₂ remains a separate molecule from H₂O.
- Normal drinking water contains only trace atmospheric H₂. Hydrogen-rich water intentionally raises the dissolved-H₂ concentration many orders of magnitude above normal equilibrium with air.
- At about 25°C and one atmosphere of pure H₂ partial pressure, water holds roughly 1.56 mg/L of dissolved H₂ at equilibrium. Higher hydrogen pressure can produce concentrations well above 1.56 mg/L according to Henry’s law.
- Concentration and dose are different. A water containing 4 mg/L does not automatically deliver 4 mg of H₂. The water volume determines the total dose.
- Dissolved H₂ is not the same thing as visible bubbles. Hydrogen micro- or nanobubbles can coexist with molecularly dissolved H₂, but bubbles alone do not tell you how much hydrogen is actually dissolved.
- H₂ must be measured directly. pH, ORP and visible bubbling are not substitutes for a valid dissolved-hydrogen measurement.
- H2HUBB independently evaluates hydrogen products. We test actual H₂ performance, total dose, repeatability, relevant safety factors and product function and compare those measurements with manufacturer claims.
What Is Hydrogen-Rich Water?
Hydrogen-rich water—also called hydrogen water, H₂ water, molecular hydrogen water or hydrogen-infused water — is drinking water containing dissolved molecular hydrogen gas.
The scientific notation for molecular hydrogen is H₂.
Hydrogen-rich water can therefore be thought of as:
This is the same general physical concept used when other gases are dissolved in liquids.
Carbonated water, for example, contains dissolved carbon dioxide. Hydrogen water contains dissolved molecular hydrogen.
But hydrogen behaves very differently from carbon dioxide.
H₂ is much less soluble, has a very small molecular size, diffuses rapidly and readily escapes from water when exposed to the atmosphere.
Isn’t There Already Hydrogen in Water? H₂ vs. H₂O
This is usually the first question people ask.
Yes—ordinary water contains hydrogen atoms.
Every water molecule contains:
- two hydrogen atoms, and
- one oxygen atom.
That is why water is written chemically as H₂O.
But the hydrogen atoms in H₂O are chemically bonded to oxygen. They are not free molecular hydrogen gas.
H₂O
A water molecule consisting of two hydrogen atoms chemically bonded to one oxygen atom.
H₂
Molecular hydrogen gas consisting of two hydrogen atoms bonded to each other.
Hydrogen Water
H₂O containing additional molecular H₂ physically dissolved in the liquid.
Not Hydrogen Peroxide
Hydrogen peroxide is H₂O₂ and is chemically different from both water and molecular hydrogen.
The H₂ Does Not Permanently Change the Water Molecule
Molecular hydrogen remains H₂ when it dissolves in water.
It does not split into protons and electrons simply because it entered the liquid, and it does not become chemically attached to ordinary H₂O molecules.
In physical-chemistry terms, it exists as aqueous molecular hydrogen.
Ordinary Water Already Contains Dissolved Gases—but Almost No H₂
Water exposed to the atmosphere naturally contains dissolved gases.
These include:
- nitrogen,
- oxygen,
- argon,
- carbon dioxide,
- and trace amounts of molecular hydrogen.
The concentration of each gas depends partly on how much of that gas is present in the atmosphere.
Atmospheric molecular hydrogen exists at only about 0.5 parts per million by volume.
That is extremely low.
When water equilibrates with ordinary air, the expected dissolved-H₂ concentration is therefore only around 0.0000009 mg/L under typical conditions.
This is why regular tap water, bottled water or filtered water is not considered hydrogen-rich water simply because H₂O contains hydrogen.
Hydrogen-rich water intentionally raises the concentration of free molecular H₂ gas dissolved in the water.
Henry’s Law Explains How H₂ Dissolves in Water
To understand hydrogen water technology, you need to understand one basic physical principle: Henry’s law.
Henry’s law describes the relationship between the partial pressure of a gas above a liquid and the amount of that gas that dissolves into the liquid at a given temperature.
In simplified form:
At approximately 25°C and about one atmosphere of pure H₂ partial pressure, molecular hydrogen has an equilibrium solubility in water of roughly:
You will frequently see this rounded to 1.6 mg/L or 1.6 ppm.
An Important Detail About the 1.6 mg/L Number
The 1.56-1.60 mg/L figure is not a universal ceiling that no hydrogen water can ever exceed.
It describes equilibrium solubility at approximately room temperature and about one atmosphere of hydrogen partial pressure.
Change the hydrogen pressure or temperature and the equilibrium concentration changes.
More Hydrogen Pressure Can Dissolve More H₂
This is one of the most misunderstood subjects in consumer hydrogen-water discussions.
People often repeat:
“Hydrogen water cannot exceed 1.6 ppm.”
That statement is physically incorrect when pressure, supersaturation or specialized preparation methods are involved.
Henry’s law predicts that increasing hydrogen partial pressure increases dissolved-H₂ concentration.
For example, if pure H₂ partial pressure were raised to approximately 50 psia, or about 3.4 atmospheres absolute, the theoretical equilibrium concentration at 25°C would be roughly 5.3 mg/L.
The exact real-world concentration depends on:
- absolute hydrogen pressure,
- water temperature,
- water volume,
- gas purity,
- gas-liquid contact area,
- bubble size,
- mixing and recirculation,
- contact time,
- container sealing,
- and how quickly the sample is measured after depressurization.
We See This in Real H2HUBB Product Testing
Modern high-pressure hydrogen water bottles can produce concentrations several times greater than the approximately 1.6 mg/L equilibrium level associated with one atmosphere of pure hydrogen.
H2HUBB has independently measured modern portable and pressurized hydrogen-water products producing several milligrams of dissolved H₂ per liter.
This is why pressure, total water volume and actual measurement matter more than repeating a universal “1.6 ppm maximum.”
Why Does H₂ Have Relatively Low Solubility in Water?
Molecular hydrogen is:
- electrically neutral,
- nonpolar,
- extremely small,
- and weakly interactive with water molecules.
Water is a polar solvent.
In general, water interacts more strongly with polar and ionic substances—such as salts and sugars—than with nonpolar gases and molecules.
H₂ therefore has relatively low water solubility.
But low solubility does not mean hydrogen water cannot contain meaningful quantities of molecular hydrogen.
H₂ has an extremely low molecular mass, so even a few milligrams represents a very large number of hydrogen molecules.
Hydrogen Water Is Not the Same Thing as Alkaline Water
This distinction is critical.
| Characteristic | Hydrogen-Rich Water | Alkaline Water |
|---|---|---|
| Defined By | Dissolved molecular hydrogen concentration | Elevated pH |
| Primary Measurement | mg/L or ppm dissolved H₂ | pH |
| Must Be Alkaline? | No | Yes, by definition |
| Can Electrolysis Produce It? | Yes | Yes |
| Can It Be Near Neutral pH? | Yes | No |
Traditional water ionizers can produce both alkaline water and dissolved molecular hydrogen at the cathode.
But modern PEM/SPE hydrogen water systems can generate and dissolve H₂ without intentionally making the drinking water alkaline.
This is why pH does not tell you how much molecular hydrogen is present.
What About ORP?
Oxidation-reduction potential, or ORP, can become more negative in the presence of dissolved hydrogen.
But ORP is also strongly influenced by pH and other redox couples in the water.
Therefore:
ORP cannot be used to reliably determine or compare dissolved molecular hydrogen concentration.
A water with a very negative ORP does not automatically contain more H₂ than another water with a less-negative ORP.
Dissolved Molecular Hydrogen vs. Nanobubbles and Visible Bubbles
This subject causes a tremendous amount of confusion.
The most important distinction is:
molecularly dissolved H₂ and hydrogen gas bubbles are not exactly the same physical state.
Hydrogen-rich water produced by electrolysis or gas infusion can contain:
- molecularly dissolved aqueous H₂,
- very small hydrogen nanobubbles,
- larger microbubbles,
- and visible undissolved gas bubbles.
Supersaturated electrolyzed water can contain both dissolved hydrogen and a dispersed hydrogen-bubble phase.
One Technical Point I Would Teach Differently Today
In some of my older educational material, I described dissolved H₂ itself as being present in the form of nanobubbles.
I would make that distinction more carefully today.
Molecular H₂ can be truly dissolved at the molecular level, while hydrogen nano- and microbubbles can coexist as a separate dispersed gas phase.
This matters because a device can visibly produce a tremendous amount of bubbling while still having poor dissolved-H₂ performance.
Can You See Dissolved Hydrogen?
No.
Truly dissolved H₂ is invisible to the naked eye.
A glass of excellent hydrogen water can look exactly like ordinary water.
The bubbles you see are gas that has not remained completely molecularly dissolved.
More visible bubbles do not automatically mean more dissolved hydrogen. If you want to know the H₂ concentration, measure the H₂ concentration.
How Long Does Molecular Hydrogen Stay in Water?
H₂ is volatile and begins moving toward equilibrium with the surrounding atmosphere as soon as conditions allow it to escape.
That is why freshly generated hydrogen water gradually loses H₂ after a container is opened.
An often-cited hydrogen pharmacokinetic review reported that saturated hydrogen water placed in an open container fell to approximately half its original concentration after around two hours and lost nearly all of its hydrogen after approximately ten hours.
But there is no universal hydrogen-water half-life.
Retention depends strongly on the product, container and environmental conditions.
What Controls H₂ Retention?
Practical H2HUBB Rule
If hydrogen water is made on demand, I generally recommend drinking it relatively soon after the cycle finishes rather than generating it and leaving it sitting open for hours.
When hydrogen water is commercially packaged, the packaging system becomes part of the technology because the package must retain H₂ throughout storage.
Hydrogen Water mg/L, ppm and ppb Explained
Dissolved molecular hydrogen concentration is commonly reported as:
- mg/L — milligrams per liter,
- ppm — parts per million,
- ppb — parts per billion.
For dilute hydrogen concentrations in water, mg/L and ppm are approximately numerically equivalent.
Therefore:
A concentration of:
- 0.8 mg/L is approximately 0.8 ppm or 800 ppb,
- 1.6 mg/L is approximately 1.6 ppm or 1,600 ppb,
- 5 mg/L is approximately 5 ppm or 5,000 ppb.
Why H2HUBB Prefers mg/L
I prefer discussing hydrogen water in mg/L because it makes the next calculation much easier:
How many milligrams of molecular hydrogen are actually in the serving?
Concentration Is Not the Same Thing as H₂ Dose
This is one of the most important concepts in the entire hydrogen-water industry.
A concentration tells us how much H₂ exists per liter.
The total H₂ dose tells us how many milligrams are actually contained in the water you drink.
Example 1
A 500 mL bottle is 0.5 liters.
If it contains 2.0 mg/L:
Example 2
A 250 mL bottle is 0.25 liters.
If it contains 6.0 mg/L:
The second water has three times the concentration, but only 50% more total H₂ because the serving is half the size.
How H2HUBB Thinks About Practical H₂ Intake
Across molecular-hydrogen research and practical consumer use, I commonly use approximately 1-3 mg of H₂ per day as a useful practical reference range for hydrogen water.
A broader range of roughly 1-15 mg H₂ per day can be encountered when looking across different clinical-study exposures, water technologies and modern higher-dose products.
These ranges are research-informed reference points—not one universal dose that every person or every health objective must use.
This is why H2HUBB evaluates both concentration and total milligrams delivered.
Want to Go Deeper Into Hydrogen Water Benefits?
This article focuses primarily on what hydrogen water is and how the physical delivery system works.
Our dedicated Hydrogen Water Benefits guide goes deeper into the human and preclinical research involving oral H₂ administration.
How Is Hydrogen-Rich Water Made?
There are multiple ways to place molecular hydrogen into drinking water.
The goal is the same: generate H₂ and get as much of it as possible into solution.
PEM / SPE Electrolysis
A proton-conducting membrane separates hydrogen production from oxygen production. H₂ is generated and then dissolved into the drinking water.
Water Ionizers
Traditional electrolysis produces cathodic alkaline water that can also contain dissolved H₂. Performance depends strongly on source-water chemistry, current, flow and system design.
Hydrogen Gas Infusion
H₂ can be generated separately and transferred into water using bubbling, membranes, mixing, recirculation or pressure.
Hydrogen Tablets
Magnesium-based formulations react in water to generate H₂. Sealed containers can allow pressure to rise and help create supersaturated hydrogen water.
Pressurized Systems
Dedicated systems increase hydrogen partial pressure and gas-liquid contact to dissolve concentrations above the one-atmosphere equilibrium level.
Prepackaged H₂ Water
Hydrogen water can be prepared commercially and packaged in materials engineered to reduce H₂ loss before consumption.
Want the Engineering Behind Each Technology?
Our technical Hydrogen Water Methods guide explains PEM/SPE cells, water ionizers, hydrogen tablets, gas infusion, source-water chemistry, pressure, packaged H₂ water and dissolved-hydrogen measurement.
How H2HUBB Measures Hydrogen Water
If a product claims to produce 2 mg/L, 5 mg/L, 8 mg/L or more, we need an analytical method capable of actually measuring dissolved H₂.
H2HUBB currently uses multiple methods depending on the product and test objective.
Unisense H₂ Microsensor
H2HUBB uses a research-grade electrochemical hydrogen microsensor and UniAmp amplifier to directly measure dissolved molecular hydrogen in real time.
Gas Chromatography
Headspace gas chromatography is a strong analytical method for determining H₂ concentration when properly performed.
H₂Blue Titration
H₂Blue can provide dependable practical measurements when sampling technique, water volume and titration procedure are tightly controlled.
Replicate Testing
We place more value on repeatable averages across multiple tests than on one unusually high peak measurement.
Why Sample Handling Matters
Because H₂ begins escaping from water immediately, poor sample technique can create a falsely low result.
Important variables include:
- how quickly the sample is collected,
- how the water is transferred,
- sample volume,
- agitation,
- temperature,
- headspace,
- measurement delay,
- and instrument calibration.
H₂Blue Technique
H2HUBB used H₂Blue extensively before moving to our current Unisense microsensor system, and it remains a useful field tool when used correctly.
- Use freshly generated hydrogen water.
- Transfer the sample gently and minimize splashing.
- Use the correct 6 mL test volume.
- Read the meniscus accurately.
- Hold the reagent consistently during titration.
- Count the drops that become colorless.
- Under the standard H₂Blue method, each cleared drop represents approximately 0.1 mg/L.
- The endpoint is reached when the blue color persists.
See the Equipment H2HUBB Uses
Our Unisense article explains why we upgraded our dissolved-H₂ testing, how the microsensor works and why direct real-time measurement matters for modern high-concentration products.
How H2HUBB Evaluates & Confirms Hydrogen Water Products
Knowing how to measure dissolved hydrogen leads directly to another important question:
How do we know whether a hydrogen water product actually performs the way the manufacturer says it does?
This is one of the main reasons H2HUBB exists.
We do not simply repeat the hydrogen concentration printed on a box, website or manufacturer specification sheet.
H2HUBB independently evaluates hydrogen products to determine what they actually deliver under real-world operating conditions.
Manufacturer Claim vs. Measured Performance
If a hydrogen water bottle is advertised at 5 mg/L, 8 mg/L or 10 mg/L, the question I ask at H2HUBB is simple:
Can we independently reproduce that performance?
We generate the hydrogen water according to the intended operating procedure, directly measure the dissolved molecular hydrogen, repeat the testing, and compare the measured performance with the manufacturer’s specifications.
Sometimes the claimed concentration is confirmed.
Sometimes the product performs better than expected.
And sometimes our measurements do not confirm the advertised hydrogen concentration.
That distinction is important for consumers because hydrogen-water marketing numbers should ultimately be supported by measured hydrogen performance.
We Test More Than One Peak Reading
One unusually high measurement does not tell me enough about a hydrogen water product.
What matters much more is whether the device can repeatedly produce qualifying H₂ performance.
Depending on the product and evaluation, H2HUBB may examine:
Dissolved Hydrogen Concentration
We directly measure the molecular hydrogen dissolved in the drinking water and report the result in mg/L.
Total Milligrams of H₂
Concentration is combined with the actual serving volume so we can determine how many milligrams of molecular hydrogen the product delivers per serving.
Repeatable Performance
We perform replicate measurements to determine whether hydrogen production is consistent rather than relying on one unusually high result.
Manufacturer Specification Verification
Measured H₂ performance can be compared with the concentration, cycle time, capacity and other performance claims made by the manufacturer.
Relevant Water-Safety Checks
Depending on the technology, evaluation may include testing for chlorine, ozone or other relevant electrolysis concerns, along with pressure, venting and product-safety features.
Practical Product Function
A hydrogen product also needs to function in a way that allows the intended H₂ exposure to be achieved under realistic consumer-use conditions.
Why H2HUBB Measures Both Concentration and Dose
This is particularly important with hydrogen water.
Consider two products:
| Example | H₂ Concentration | Water Volume | Total H₂ |
|---|---|---|---|
| Product A | 3 mg/L | 500 mL | 1.5 mg H₂ |
| Product B | 5 mg/L | 200 mL | 1.0 mg H₂ |
Product B has the larger concentration number.
But Product A actually delivers more molecular hydrogen in the full serving.
This is why H2HUBB does not rank hydrogen water products based on ppm alone.
The question is not simply, “How many ppm does this device make?” The question is, “How much molecular hydrogen does the consumer actually receive, and can the product deliver it consistently and safely?”
Our Hydrogen Water Evaluation Process
H2HUBB Approval Comes After Evaluation
H2HUBB combines an independent product-evaluation wing with a qualified hydrogen marketplace.
Our evaluation process comes before approval and recommendation.
Products are tested against category-specific performance requirements rather than receiving approval simply because a company wants to be listed on H2HUBB.
A qualifying hydrogen-water product should demonstrate appropriate H₂ performance, dose, consistency, safety and practical functionality for its category.
Different Hydrogen Water Products Require Different Evaluations
There is no single test protocol that makes sense for every hydrogen-water technology.
Portable Hydrogen Water Bottles
We evaluate cycle-specific concentration, bottle volume, total H₂ dose, repeatability and relevant PEM/SPE performance and safety characteristics.
Hydrogen Water Pitchers
Larger volumes change the relationship between concentration and total H₂ dose, making capacity, mixing and hydrogen distribution particularly important.
Pressurized H₂ Systems
Pressure, recirculation, release conditions and sample timing become critical because H₂ concentration can change rapidly after pressure is released.
Hydrogen Tablets
We evaluate the H₂ produced from the complete reaction, concentration over time, water volume and approximate milligrams of H₂ delivered per tablet.
Flow-Through Systems
Flow rate, water chemistry, electrolysis current and actual output under realistic use conditions become important performance variables.
Packaged Hydrogen Water
The concentration at production is only part of the question. H₂ retention through packaging, storage and the point of consumption is also important.
H2HUBB Product Pages Show the Results
When H2HUBB has independently tested a hydrogen water product, our product pages are designed to show consumers more than basic specifications.
Depending on the product, you may find:
- the independently measured H₂ concentration,
- average and peak results,
- total H₂ dose per serving,
- the tested cycle or operating mode,
- H2HUBB’s testing procedure,
- manufacturer claims compared with measured results,
- relevant safety testing,
- product specifications,
- H2HUBB approval information,
- and current purchasing information when applicable.
The purpose is to let consumers compare hydrogen products based on what they actually deliver—not just what is advertised.
See Independently Evaluated Hydrogen Products
H2HUBB’s marketplace connects hydrogen education with actual product-performance data.
Compare hydrogen water products, review independent measurements, and see which products have successfully met the applicable H2HUBB requirements.
How Not to Measure Hydrogen-Rich Water
There are several shortcuts that can create misleading hydrogen-water claims.
At H2HUBB, I care far more about the H₂ actually dissolved in the water when someone drinks it than the number displayed on a marketing screen.
Why Are People Drinking Hydrogen-Rich Water?
The reason people drink hydrogen water is not because adding H₂ makes the water hydrate you better in some mysterious way.
Hydrogen water is an oral administration method for molecular hydrogen.
Once consumed, H₂ can be absorbed through the gastrointestinal tract, enter portal circulation and the liver, and then distribute more broadly.
Hydrogen water creates a relatively rapid, transient H₂ exposure compared with the sustained exposure that can be produced through inhalation.
Published hydrogen-water research has investigated therapeutic effects involving:
Redox Regulation
Oxidative-stress regulation and endogenous antioxidant signaling.
Inflammation
Cytokines, inflammatory pathways and immune regulation.
Mitochondria
Cellular energy metabolism and mitochondrial function.
Metabolism
Glucose, insulin sensitivity, lipids and metabolic signaling.
Exercise
Fatigue, lactate, perceived exertion and recovery outcomes.
Cardiovascular Function
Vascular, endothelial and cardiovascular research.
Neurological Research
Cognition, neuroprotection and neurological disease models.
Cellular Protection
Gene expression, apoptosis, DNA damage and adaptive signaling.
The hydrogen-water research spans human and preclinical studies involving exercise, cardiovascular function, liver health, metabolic outcomes, oxidative stress, inflammation, neurological function and other areas.
This Is Only the Introduction to the Health Research
We have a separate article dedicated entirely to what the hydrogen-water literature shows across different health outcomes.
Is Hydrogen-Rich Water Safe?
Molecular hydrogen has demonstrated a favorable tolerability profile throughout the human research literature.
H₂ is also not foreign to human biology.
Gut bacteria naturally generate substantial quantities of molecular hydrogen through fermentation, and H₂ can enter the circulation following intestinal production.
For hydrogen water, I separate two different safety questions:
Is Molecular H₂ Well Tolerated?
Published human research has generally reported favorable tolerability for orally administered hydrogen-rich water.
Is the Product Producing Safe Drinking Water?
This depends on the water source, electrolysis architecture, materials, maintenance and whether unwanted byproducts such as chlorine or ozone enter the drinking water.
This second question is why H2HUBB does more than simply test whether a device makes hydrogen.
Depending on the technology, our evaluations can include:
- dissolved-H₂ performance,
- total H₂ dose,
- chlorine testing,
- ozone testing,
- pH changes,
- source-water requirements,
- pressure and venting design,
- electrolytic-cell performance,
- and overall product function.
What Should You Look for in a Hydrogen Water Product?
Once you understand what hydrogen water actually is, evaluating products becomes much easier.
I would focus on these questions:
H2HUBB Does Not Approve Hydrogen Water Based on PPM Alone
Our product-performance framework evaluates concentration, total H₂ dose, consistency, safety and practical use.
For hydrogen-water products, H2HUBB evaluates whether the product delivers a meaningful amount of molecular hydrogen within the intended serving and use pattern.
Different hydrogen-water categories have different requirements because a 250 mL portable bottle, a 2 L pitcher, a flow-through system, a tablet and a packaged drink are not the same delivery system.
See the Standard Behind H2HUBB-Approved Hydrogen Water
My Answer Today: What Is Hydrogen Water?
If someone asks me today, “What is hydrogen water?” my short answer is:
Hydrogen-rich water is ordinary drinking water used as a delivery system for dissolved molecular hydrogen gas, H₂.
But once you understand the science, there is a second part:
Good hydrogen water is not defined by the word hydrogen on the bottle.
It is defined by how much molecular H₂ is actually dissolved in the water, how much total H₂ the serving delivers, whether that concentration is repeatable, how well the water retains it, and whether the product produces it safely.
That distinction is exactly why independent product evaluation is such an important part of H2HUBB.
We use the science discussed throughout this article—hydrogen solubility, pressure, concentration, dose, retention and analytical measurement—to evaluate the actual products consumers are being asked to purchase.
We test hydrogen products to determine what they actually produce, compare those measurements with manufacturer claims, evaluate repeatability and relevant safety factors, and only then determine whether the product meets the applicable H2HUBB requirements.
That creates the bridge between molecular-hydrogen research, hydrogen-water science and the real products available to consumers.
Hydrogen water itself is a simple concept.
Accurately producing, retaining, measuring, confirming and delivering meaningful amounts of molecular hydrogen is where the real science, engineering and independent evaluation begin.
Continue Learning About Hydrogen Water
Hydrogen Water Frequently Asked Questions
What is hydrogen-rich water?
Hydrogen-rich water is drinking water containing additional dissolved molecular hydrogen gas, H₂. The H₂ remains chemically separate from the H₂O molecules.
Isn’t there already hydrogen in regular water?
Yes, but the hydrogen atoms in ordinary H₂O are chemically bonded to oxygen.
Hydrogen-rich water contains additional free molecular hydrogen gas, H₂, dissolved in the liquid.
Is hydrogen water the same thing as alkaline water?
No.
Hydrogen water is defined by dissolved H₂ concentration. Alkaline water is defined by elevated pH.
Some electrolysis systems produce both at the same time, but the two properties are separate.
What is the normal saturation concentration of H₂ in water?
At approximately 25°C and about one atmosphere of pure hydrogen partial pressure, the equilibrium solubility is approximately 1.56-1.60 mg/L.
Higher hydrogen pressure can increase dissolved concentration beyond this level.
Can hydrogen water exceed 1.6 ppm?
Yes.
Higher hydrogen partial pressure and supersaturation can produce concentrations above the approximately 1.6 mg/L equilibrium level associated with one atmosphere of H₂.
H2HUBB routinely tests modern hydrogen-water products capable of producing several milligrams per liter.
Is dissolved H₂ made of nanobubbles?
Molecularly dissolved H₂ and hydrogen nanobubbles should be distinguished.
Hydrogen water can contain aqueous molecular H₂ together with micro- or nanobubbles depending on how it was generated.
Visible or microscopic bubbles are not themselves a direct measurement of dissolved-H₂ concentration.
How long does H₂ remain in hydrogen water?
There is no single fixed half-life.
H₂ loss depends on container material, sealing, headspace, temperature, agitation, surface area, starting concentration and time after opening.
Hydrogen water made on demand is generally best consumed relatively soon after production.
Is ppm the same as mg/L for hydrogen water?
For dilute H₂ concentrations in water, mg/L and ppm are approximately numerically equivalent.
For practical hydrogen-water calculations, 1 mg/L is approximately 1 ppm or 1,000 ppb.
How do I calculate the amount of H₂ in a bottle?
Multiply the dissolved-H₂ concentration in mg/L by the water volume in liters.
For example, 4 mg/L in 250 mL, or 0.25 L, contains approximately 1 mg of H₂.
Can ORP measure hydrogen concentration?
No.
ORP can be influenced by dissolved hydrogen, but it is also strongly influenced by pH and other redox chemistry.
H₂ concentration should be measured directly with an appropriate hydrogen-specific analytical method.
How does H2HUBB measure hydrogen water?
H2HUBB currently uses a research-grade Unisense Hydrogen Microsensor with a UniAmp amplifier for direct real-time dissolved-H₂ measurement.
We have also used H₂Blue titration extensively and may use additional analytical or third-party laboratory methods when appropriate.
How does H2HUBB confirm manufacturer hydrogen claims?
H2HUBB independently operates the product under defined conditions, directly measures its H₂ output, performs repeat testing and compares representative measured performance with the manufacturer’s advertised specifications.
Depending on the product category, we may also evaluate total H₂ dose, relevant water-safety factors, consistency, pressure, operation and practical product function.
Does H2HUBB approve every hydrogen product it tests?
H2HUBB approval follows evaluation.
A product must meet the applicable H2HUBB performance and category requirements before it qualifies for approval and marketplace recommendation.
Does hydrogen-rich water have health benefits?
Hydrogen-rich water is an oral method of administering molecular hydrogen, which has pleiotropic biological effects involving redox regulation, inflammation, mitochondria, metabolism, cellular signaling and other systems.
Human hydrogen-water research has investigated exercise, metabolic health, cardiovascular function, liver function, inflammation, oxidative stress, cognition and other areas.
See H2HUBB’s dedicated Hydrogen Water Benefits article for the detailed research.
H2HUBB Education & Evaluation Note
H2HUBB discusses hydrogen-rich water from a research, education and therapeutic-potential perspective.
Our product evaluations are intended to determine whether hydrogen products perform according to measurable technical and category-specific standards.
Individual medical decisions should account for a person’s condition, existing treatments, hydrogen exposure and appropriate professional guidance when needed.
References & H2HUBB Resources
- H2HUBB — Hydrogen Water Benefits: What the Research Shows
- H2HUBB — Molecular Hydrogen Health Benefits & Therapeutic Potential
- H2HUBB — How Hydrogen Water Is Made
- H2HUBB — Molecular Hydrogen Administration Methods
- H2HUBB — Hydrogen Water vs. Hydrogen Inhalation
- H2HUBB — Unisense Hydrogen Microsensor & H₂ Testing
- H2HUBB — Hydrogen Product Performance Standards
- H2HUBB — Independently Evaluated Hydrogen Water Products
- H2HUBB Molecular Hydrogen Research Library
- LeBaron TW, Sharpe R, Ohno K. Electrolyzed–Reduced Water: Review I. Molecular Hydrogen Is the Exclusive Agent Responsible for the Therapeutic Effects. View Review
- Dhillon G, Buddhavarapu V, Grewal H, et al. Hydrogen Water: Extra Healthy or a Hoax?—A Systematic Review. International Journal of Molecular Sciences. 2024;25(2):973. View Systematic Review
- Oral Administration of Hydrogen-rich Water: Biomedical Activities, Potential Mechanisms, and Clinical Applications. Current Pharmaceutical Design. 2025;31(19):1537-1550. View Review
- Liu B, Jia X, Xue J, Qin S. Determination of Hydrogen Concentration in Hydrogen-rich Water by Headspace Gas Chromatography and Hydrogen Microelectrode. 2023. View Measurement Study
- Kikuchi K, Tanaka Y, Saihara Y, et al. Concentration of hydrogen nanobubbles in electrolyzed water. Journal of Colloid and Interface Science. 2006;298(2):914-919. View Study
- Liu BY, Qin SC. Different types of molecular hydrogen donors and their pharmacokinetics in vivo. 2019. View on PubMed