The Science Behind a Hydrogen Rich Bath Explained Simply
A warm bath already gives us time to slow down. H Fizz® Onsen adds something different: freshly generated molecular hydrogen, dissolved directly into the bathwater.
Using Japanese-designed technology, H Fizz Onsen combines SPE/PEM electrolysis, high-flow water circulation and fine nano-bubbles to create hydrogen-rich water around the body. The result is an elegant, spa-like ritual that brings hydrogen bathing into the comfort of your own home.
But how does it actually work? Let us take you inside the process.
What Is a Hydrogen Bath
Ordinary water is H₂O: each water molecule contains two hydrogen atoms chemically joined to one oxygen atom. A hydrogen bath contains something additional—dissolved molecular hydrogen gas, written as H₂. Molecular hydrogen is colourless, odourless and tasteless.
That distinction matters. The hydrogen in H₂O is locked into the water molecule. H Fizz Onsen generates free H₂ molecules and dissolves them into the bathwater, where they remain for a limited time before naturally dispersing into the air.
How H Fizz Onsen Creates Hydrogen Rich Bathwater
Step 1: Purified Water Powers the Electrolysis Process
The machine's internal reservoir is filled with the purified / distilled water. This clean water protects the electrolysis cell and helps the system operate consistently.
The water inside the machine is used to produce hydrogen. It should not be confused with the much larger volume of ordinary bathwater in the tub.
Step 2: SPE/PEM Technology Separates Hydrogen from Water
Inside the machine, an electrical current passes through a specialised electrolysis cell. Its Solid Polymer Electrolyte and Proton Exchange Membrane—usually shortened to SPE and PEM—help separate water into hydrogen and oxygen.
The membrane guides hydrogen ions to one side of the cell, where they receive electrons and form molecular hydrogen gas. Oxygen is produced separately and discharged through its own pathway. This separation is designed to generate high-purity hydrogen without adding salts or chemical agents to the bathwater.
Step 3: The Bathwater Is Continuously Circulated
H Fizz Onsen draws water from the bath through an inlet hose, introduces freshly generated hydrogen and returns the hydrogen-enriched water through its outlet and fine-bubble diffuser.
Its high-flow circulation system helps distribute hydrogen more evenly throughout the tub instead of concentrating it around one small area.
Step 4: Nano Bubbles Help Hydrogen Dissolve
Large gas bubbles rise quickly and escape at the surface. Much smaller bubbles have a greater surface area relative to their volume and remain in contact with the water for longer. This gives more of the molecular hydrogen an opportunity to dissolve.
H Fizz Onsen uses a fine-bubble diffusion system to create micro- and nano-scale bubbles. When the machine starts, the water around the outlet may briefly look soft, white or milky. This effect comes from countless tiny bubbles—not from any added substance.
Step 5: Fresh Hydrogen Builds in the Bath
Under the specified operating conditions, H Fizz Onsen can produce a bathwater hydrogen concentration of up to 3 ppm. In water, 3 ppm is approximately 3 milligrams of dissolved hydrogen per litre.
The concentration achieved in any individual bath can vary with water volume, temperature, circulation time, hose position, room ventilation and the method used to take the measurement. Because hydrogen is a very light gas and naturally leaves water over time, it is best generated fresh and enjoyed soon after—or while—the cycle is running.
Why Nano Bubbles Matter
Nano-bubbles are an important part of the H Fizz Onsen experience for three reasons:
- More contact with water: smaller bubbles provide more surface area for hydrogen to move into the water.
- Better distribution: continuous circulation helps carry hydrogen-rich water around the bath.
- A fresher bath: hydrogen is generated during the session instead of being added long beforehand and allowed to dissipate.
This combination of fresh generation, fine bubbles and water circulation is what turns an ordinary bath into a hydrogen-rich bath.
What Happens While You Soak
As you bathe, hydrogen-rich water surrounds the skin across a large surface area. Molecular hydrogen is unusually small, which is one reason researchers are interested in how it may interact with biological tissues and influence redox and inflammatory signalling.
Early studies have explored hydrogen-water bathing in relation to skin appearance, inflammatory skin conditions, oxidative stress and post-exercise recovery. Some participants in published research have shown encouraging changes, but the evidence remains at an early stage.
It is also helpful to separate the effects of hydrogen from the familiar effects of warm water. Warm bathing itself can relax the body and temporarily soften the skin. The added purpose of H Fizz Onsen is to introduce freshly dissolved molecular hydrogen as part of that restorative ritual.
What the Research Says
Research into molecular hydrogen has expanded over the past two decades. Laboratory work and early human studies suggest that H₂ may influence oxidative-stress and inflammation-related pathways. Scientists are still working to understand the exact biological mechanisms and the doses, delivery methods and conditions in which hydrogen may be most useful.
A 2018 study published in Scientific Reports observed improvements among patients with psoriasis and parapsoriasis following a course of hydrogen-water bathing. Another human study reported short-term changes in serum antioxidant capacity and inflammation-related measurements after bathing in hydrogen-rich water made with nano-sized bubbles.
Figure 1: Clinical improvement of psoriasis and parapsoriasis en plaques following an 8-week course of hydrogen-water bathing. Source: Zhu Q, et al. Scientific Reports, 2018.
A 2024 systematic review likewise concluded that early findings on hydrogen-rich water are encouraging while emphasising the need for larger studies with more rigorous methods.
Figure 2: Reduction in wrinkle degree following hydrogen warm-water bathing over 43–61 days. Source: Tanaka Y, et al. Medical Gas Research, 2021.
At H Fizz, we believe the most responsible approach is to follow the science with both interest and care: share what has been observed, explain the limits of current evidence and never promise the same result for everyone.
Designed for a Premium At-Home Ritual
H Fizz Onsen brings together:
- Japanese-designed hydrogen-bath technology
- Advanced SPE/PEM electrolysis
- Micro- and nano-bubble diffusion
- High-flow hydrogen production of 6,000 mL per minute
- Dissolved hydrogen concentration of up to 3 ppm under specified conditions
- Quiet operation for a calm, spa-like experience
- Built-in water-level, water-quality and temperature monitoring
- Overheat protection and automatic safety controls
- UV-supported hygiene system
- CE certification
The technology is sophisticated, but the experience is deliberately simple: prepare the machine, fill the bath, start the cycle and soak.
Making Hydrogen Bathing Part of Your Routine
For best results, always follow the H Fizz Onsen user manual. Use distilled water in the machine's internal reservoir, keep both bath hoses correctly positioned and allow the system time to enrich and circulate the water. A session of at least 15 minutes gives you time to settle into the experience.
If you wish to use bath salts, oils or other additives, remove the hoses first and follow the care instructions to protect the pump, filter and diffuser. Operate the machine in a well-ventilated bathroom and keep it away from flames or other ignition sources.
Hydrogen naturally dissipates after generation stops, so there is little benefit in preparing the bath hours in advance. Fresh is best.
A More Considered Kind of Bath
H Fizz Onsen is where advanced hydrogen technology meets one of the simplest forms of self-care. It does not ask you to add another complicated step to your day. It simply transforms time already spent in the bath into a more considered ritual for skin, body and mind.
Fill. Switch on. Soak. Let your bathroom become your own private onsen.
Would you like to experience H Fizz Onsen? Contact Harmony Central to arrange a demonstration or learn whether it is the right addition to your home or wellness space.
Research Referenced
- Zhu Q, et al. Positive effects of hydrogen-water bathing in patients of psoriasis and parapsoriasis en plaques. Scientific Reports. 2018.
- Tanaka Y, et al. Hydrogen-rich bath with nano-sized bubbles improves antioxidant capacity based on oxygen radical absorbing and inflammation levels in human serum. Medical Gas Research. 2021.
- Dhillon G, et al. Hydrogen Water: Extra Healthy or a Hoax?—A Systematic Review. International Journal of Molecular Sciences. 2024.
Important Note
H Fizz Onsen is intended for general wellness and is not a substitute for professional medical advice, diagnosis or treatment. Research into molecular hydrogen and hydrogen-water bathing is continuing, and individual experiences vary. If you have a medical condition, an active skin problem or any concern about bathing safely, consult a qualified healthcare professional before use. Always operate the product according to its official instructions.
