Molecular Hydrogen Water: What It Is and How It Is Used
TL;DR. Molecular hydrogen water is ordinary water with hydrogen gas (H2) dissolved in it. The most common way to make it at home is an effervescent tablet, often based on magnesium, that fizzes and releases hydrogen when dropped into water; electrolysis bottles are the other route. Hydrogen is a very small, light gas that escapes quickly from an open glass, which is why how you prepare and drink it matters. Human research is still early and limited, and there is no authorised EU health claim for molecular hydrogen, so this guide describes what it is and how it is used, not what it does. This is information, not medical advice.
What is molecular hydrogen water?
Molecular hydrogen water is plain drinking water that has hydrogen gas, written as H2, dissolved in it. Hydrogen is the smallest and lightest molecule there is, made of two hydrogen atoms. It has no colour, no smell and no taste, so hydrogen water looks and tastes like normal water. The hydrogen is not bound to the water in the way that the H in H2O is; it is simply dissolved as a gas, in the same way that carbon dioxide is dissolved in sparkling water.
Because the gas is only dissolved and not chemically attached, it does not stay in the water forever. Once the water is exposed to air, the hydrogen gradually leaves, which is why the container and the timing of drinking are part of the topic rather than an afterthought.
How do products make hydrogen water?
There are two common methods, and they work in very different ways.
The first is an effervescent tablet. These tablets are often based on elemental magnesium together with a food acid. When the tablet is dropped into a glass or bottle of water, it reacts and fizzes, and that reaction releases hydrogen gas into the water. The tablet dissolves, the bubbles carry hydrogen, and some of that gas stays dissolved in the liquid. This is a chemical route that needs only water and a tablet.
The second is an electrolysis bottle or generator. Here an electric current is passed through the water, splitting some of it and producing hydrogen gas inside the bottle, which then dissolves into the water. This is an electrical route that needs power and a device rather than a consumable tablet.
Both aim at the same end result, water with hydrogen dissolved in it. They differ in cost, convenience, how repeatable the result is, and how the gas is kept in the water.
What does concentration mean?
The amount of hydrogen dissolved in water is usually described as a concentration, in parts per million (ppm) or as milligrams of hydrogen per litre. As a general idea, a higher figure means more gas is dissolved in the same volume of water. Because hydrogen is so light, the actual mass dissolved is always very small.
Two honest points matter here. First, hydrogen is only slightly soluble in water, so there is a natural ceiling to how much can dissolve at normal pressure. Second, any figure is a snapshot at the moment of preparation; the concentration falls as the gas escapes into the air. A number on its own does not tell you how much hydrogen is still present by the time you drink, which depends on the method, the container and the time elapsed.
Tablet in a sealed glass or an open bottle: what is the difference?
Because hydrogen is such a small, light gas, it escapes from water quickly once there is open air above it. How you hold the gas in changes how much stays dissolved. The comparison below is descriptive.
| Setup | How the gas behaves | General characteristic (informative) |
|---|---|---|
| Tablet in a sealed container | Pressure builds as the tablet fizzes, helping more gas stay dissolved | Designed to keep hydrogen in the water until opening |
| Tablet in an open glass | Hydrogen escapes into the air as it forms and afterwards | Simple, but more gas is lost before drinking |
| Electrolysis bottle | Gas is generated inside and dissolves, then escapes once opened | Repeatable device, result still falls over time in air |
| Pre-bottled hydrogen water | Sealed at the source, but a permeable bottle lets gas leave slowly | Packaging material and storage time affect what remains |
The common thread is simple physics: a sealed environment helps keep the gas dissolved, while open air lets it leave. This is why many tablet products are used in a filled, sealed glass or bottle and consumed without long delay.
How do people use hydrogen water?
In practice, people usually prepare it fresh and drink it without waiting. With a tablet, that means filling a glass or bottle, dropping in the tablet, letting it dissolve, and drinking once it has finished reacting. With an electrolysis device or pre-bottled water, it means drinking soon after generating or opening it. The shared idea across methods is to drink while the gas is still dissolved, because an open container loses hydrogen over time. Our own tablet-based approach is described on our molecular hydrogen. None of this implies a health outcome; it simply reflects how the gas behaves.
What does the research say?
This is where honesty matters most. Human research on molecular hydrogen water is still early and limited. Researchers have studied hydrogen water in a number of small trials and laboratory settings, but the studies are mostly small, vary in design, and do not add up to settled conclusions. Early findings are not the same as proven effects, and a single small study is not a reason to expect a particular result.
Crucially, there is no authorised EU health claim for molecular hydrogen. That means no health benefit, of any kind, may be presented as established fact. For that reason this article, and a responsible brand, will tell you what hydrogen water is, how it is made and how the gas behaves, rather than promising what it will do for you. Saying that scientists have looked at a topic is not the same as saying the topic is proven, and we keep that line clear.
Is hydrogen water safe?
Hydrogen water is generally regarded as low-risk for healthy adults, because it is water with a tiny amount of an inert, non-toxic gas dissolved in it, and the gas itself is not a medicine. That said, it is not a treatment and should not be used as one. Effervescent tablets are often magnesium based, and magnesium taken in higher amounts can have a laxative effect, so follow the product instructions and stay within the recommended use. If you are pregnant or breastfeeding, take medication, or have a medical condition such as reduced kidney function, talk to a doctor or pharmacist first. A hydrogen generating device should be used according to its own safety instructions. Supplements and functional drinks are not a substitute for a varied diet or medical care.
Frequently asked questions
What is molecular hydrogen water?
It is ordinary drinking water with hydrogen gas (H2) dissolved in it. The hydrogen is not bound to the water; it is simply dissolved as a gas, much like the carbon dioxide in sparkling water, and it leaves the water once exposed to air.
How do hydrogen tablets work?
An effervescent tablet, often based on magnesium and a food acid, reacts when dropped into water and fizzes, releasing hydrogen gas that dissolves into the liquid. The tablet itself dissolves in the process.
What is the difference between tablets and an electrolysis bottle?
A tablet creates hydrogen through a chemical reaction in the water and needs only water and the tablet. An electrolysis bottle passes an electric current through the water to generate hydrogen and needs power and a device. Both aim at water with hydrogen dissolved in it.
Why does a sealed container matter?
Hydrogen is a very small, light gas that escapes quickly into open air. A sealed glass or bottle helps keep the gas dissolved until you drink, whereas an open container loses hydrogen over time.
Does hydrogen water have an EU health claim?
No. There is no authorised EU health claim for molecular hydrogen, and the human research is still early and limited. That is why we describe what hydrogen water is and how it is used, not what it does for your health.
References
- Regulation (EC) No 1924/2006 on nutrition and health claims made on foods (governs health claims on foods and food supplements in the EU).
- EU Register of nutrition and health claims made on foods (no authorised health claim is listed for molecular hydrogen). ec.europa.eu
- General reference on the chemistry and solubility of hydrogen gas (H2) in water (standard chemistry and physical-property sources).
Written by the NOTFORTOMORROW Editorial Team. How we research: we base factual statements on the official EU claims register and on general scientific sources, we cite our sources, and we date our reviews. This article is information, not medical advice; talk to a qualified professional about your situation. Last reviewed: 2026-06-06.