Sometimes, you don’t know what you don’t know.
That truth applies to both consumers investing in a hydrogen inhalation device and those who work within the hydrogen industry itself.
For manufacturers and professionals, certain industry practices are so standard that they’re often assumed to be common knowledge. But for new consumers, these same practices can seem strange—or even concerning—because they’re unfamiliar with how the technology works.
This article aims to close that knowledge gap on both sides, focusing specifically on PEM hydrogen inhalation devices and why they contain water when shipped to your home.
What Is a PEM Hydrogen Inhalation Device?
In short, PEM (Proton Exchange Membrane) or SPE (Solid Polymer Electrolyte) hydrogen inhalation devices generate >99.9% pure hydrogen gas using distilled (deionized) water.
They are one of the four main types of hydrogen inhalation technologies available today. (You can learn more about all four classes in our article, “Hydrogen Inhalation Therapy: The Ultimate Guide.”)
PEM devices use a solid-state electrolyte membrane that separates hydrogen and oxygen gases during electrolysis, ensuring only pure hydrogen reaches the user.
Why PEM Membranes Must Stay Hydrated
PEM membranes must stay wet to function properly. This fact is so well known within the industry that most companies don’t even think to mention it—similar to how a car dealership doesn’t need to tell you that your new vehicle contains oil and gasoline. Those are simply assumed because they’re essential for operation and testing before delivery.
However, unlike the automotive industry—which is mainstream and mature—the therapeutic hydrogen industry is still developing. Many consumers are discovering hydrogen therapy for the first time and may not yet be familiar with its technology or maintenance requirements.
How PEM Membranes Work
PEM membranes are semi-permeable cation-exchange materials that allow protons (hydrogen ions) to pass through while blocking other ions.
Their function relies on water molecules trapped within the membrane. Protons move across the membrane via the Grotthuss mechanism (proton hopping), where they transfer charge by forming and breaking hydrogen bonds between water molecules.
This process creates electro-osmotic drag, in which water molecules are pulled along with the migrating protons—helping the membrane remain moist during operation.
If the membrane dries out, it loses proton conductivity, becomes brittle, and can permanently degrade. Hydration, therefore, is critical for longevity and optimal hydrogen output.
Because of this, PEM membranes in all hydrogen technologies—including inhalation units, hydrogen water machines, and hydrogen bottles—must retain internal moisture from manufacturing through operation. Dehydration is typically not an issue unless the device is mishandled or stored for prolonged periods in dry conditions.
Why Your Device May Contain Water at Delivery
When new consumers open their hydrogen inhalation device and notice some residual water, it often raises concern. However, this is completely normal and intentional.
All PEM-based hydrogen inhalation units are shipped with water content inside for two main reasons:
- To maintain hydration of the PEM membrane during storage and transit.
- Because of quality control (QC) testing before shipment.
Each unit is tested by the manufacturer using distilled (deionized) water to confirm proper operation, safety, and hydrogen output. The water remains inside the sealed internal hydrogen electrolytic cell to keep the cell hydrated and ready for use.
To put this into perspective, think of refrigerators or air conditioners shipped with refrigerant already inside. The refrigerant ensures the system is ready to function out of the box. Similarly, hydrogen inhalation devices require their “medium”—distilled water—to be present to ensure reliability and performance.
This does not mean you received a used or refurbished unit.
On the contrary, it means your device passed its QC inspection and was shipped exactly as intended.
What About Mold or Bacterial Growth?
Understandably, some consumers worry that the residual water might cause mold or bacterial contamination. However, the design of PEM hydrogen inhalation devices makes this extremely unlikely.
Here’s why:
- Distilled water contains no minerals, ions, or organic material—the nutrients microbes need to grow.
- The system is closed, minimizing air exposure.
- Regular use naturally cycles and consumes water through normal operation requiring refilling the device often.
- Most manufacturers recommend draining and refilling the reservoir monthly, further reducing any risk.
- Routine hygiene practices—such as washing your hands, disinfecting the reservoir lid and threads before refilling, and using only pure distilled water—virtually eliminate microbial contamination.
In nine years of experience testing and operating PEM hydrogen inhalation units, I have never seen a single case of mold development, even in devices stored for extended periods without use.
Final Thoughts
It’s easy to understand why new users might be surprised to find water inside their hydrogen inhalation device. However, this is standard, necessary, and beneficial for maintaining the integrity of the PEM system and ensuring your device performs at its highest level.
So, on behalf of the industry—we apologize for not mentioning it sooner.
But now you know: that bit of water inside your unit is not a defect—it’s a sign of quality assurance and optimal performance.
If you’re exploring hydrogen inhalation therapy, we encourage you to read our complete guide on Hydrogen Inhalation Therapy and purchase only from H2HUBB third-party approved devices.
It’s the safest, most scientifically validated way to ensure you’re getting a true therapeutic hydrogen experience.