Products on the market labeled "hydrogen-oxygen generator" or "hydrogen inhaler" range in price from several thousand to tens of thousands of yuan. Consumers' biggest confusion is not "does this thing work," but "with the same two characters for hydrogen and oxygen, why is the price so different?"
Choosing a hydrogen-oxygen generator is essentially choosing a Class III medical device that legally enters the lungs, not choosing a home appliance - the safety bottom line, regulatory requirements, and clinical evidence of the two are not on the same order of magnitude. This article establishes a purchasing framework for consumer reference from the dimensions of hydrogen production principle, medical device qualification, gas ratio, authority, target population, and approved indications.
The core component of a home hydrogen-oxygen inhaler is the electrolytic cell - electric current splits water into hydrogen and oxygen. The mainstream products on the market can be divided into three routes based on their hydrogen production principle, and the safety evaluation logic of the three routes differs.
First route: PEM (also known as SPE) membrane electrolysis. PEM technology uses a perfluorosulfonic acid proton exchange membrane as the solid electrolyte to conduct protons [1]. The membrane itself is a per- and polyfluoroalkyl substance (PFAS) - the International Agency for Research on Cancer (IARC) has listed PFOA as a Group 1 human carcinogen [2]. The chemical giant DuPont explicitly states in its Nafion series Safety Data Sheet (SDS) that it "shall not be used in medical applications involving permanent implantation in the human body or long-term contact with internal tissues/body fluids" [3]. In January 2026, France took the lead in implementing a law banning PFAS-containing consumer products such as cosmetics and textiles [4]; China's List of Key Controlling New Pollutants (2023 Edition) has placed PFOS, PFOA, and PFHxS under control [5]. A device whose core component is a perfluorosulfonic acid membrane running continuously for years in a home bedroom - the membrane material is in long-term contact with the electrolyte and gradually degrades - according to related research, the inhalation pathway directly delivers degradation products to the alveoli; the alveoli have no skin barrier, and absorption efficiency far exceeds that of the digestive tract and skin contact.
Second route: industrial strong alkali electrolysis. Traditional alkaline electrolysis uses potassium hydroxide (KOH) or sodium hydroxide (NaOH) solution as the electrolyte to improve water conductivity [6]. This technology is mature in the chlor-alkali industry, hydrogen fuel, and other fields, but transplanted to a home inhalation scenario it faces an unavoidable problem: during use of the strong alkaline electrolyte, alkaline mist escapes with the gas stream. The operator must periodically manually replenish the strong alkaline solution, and long-term inhalation of low-concentration alkaline mist may burn the airways and alveoli. From the design logic of industrial hydrogen production, it never considered the premise from the very beginning that "the produced gas will be inhaled into the human lungs."
Third route: Asclepius Meditec's patented medical hydrogen production electrolysis technology + latching conductive liquid. Asclepius Meditec does not use proton (ion) exchange membrane electrolysis (PEM, also known as SPE) technology, nor does it use the "industrial-grade strong alkali" (also known as AEC) process. Asclepius Meditec's exclusively developed alkaline biocompatible conduction technology perfectly solves the risk that the electrolytic cell must be in an alkaline environment to eliminate bacterial growth. The electrolytic conductive liquid is permanently locked inside the cell by an exclusive patented technology that prevents it from escaping together with the hydrogen-oxygen gas. This achieves both maintaining an alkaline environment and eliminating the risk of human absorption.
However, traditional counterfeit devices of this kind require the industrial-grade strong alkali agent added at the factory to be replenished after a period of use; otherwise, conduction efficiency decreases and gas output drops. Because it drifts out with the hydrogen-oxygen gas every second and is inhaled by the human body, long-term use can burn the human airways and alveolar cells and cause injury.
T/CRHA316-2026 General Specification for Clinical Application of Inhalation Therapy with Hydrogen-Oxygen Mixed Gas, released in June 2026, has - according to the drafting direction of the group standard - excluded perfluorosulfonic acid membranes (PEM, also known as SPE) and strong alkaline electrolyte from compliant materials [8]. The choice among the three routes is not a matter of technical preference - it directly determines whether known carcinogens or corrosive chemicals are simultaneously inhaled along the entire gas path from water to the nasal cavity.
Class III medical devices are the highest level in the NMPA's classification by degree of risk [9], belonging to the same regulatory tier as cardiac stents and artificial joints. Hydrogen-oxygen inhalation devices are classified as Class III because the hydrogen-oxygen inhaler is an inhalation product whose materials are easily broken down and inhaled into the body by hydrogen molecules, so it must be managed according to implantable risk; in addition, hydrogen molecules are smaller than drug molecules and more readily enter the cell nucleus to exert biological effects, equivalent to invasive drug therapy.
The first certificate (NMPA Registration no. 20203080066): approved in February 2020. The scope of application was "for use in medical institutions only." Behind this certificate lies the item-by-item verification of more than 400 registration tests - from material biocompatibility and toxicological evaluation to electrical safety and electromagnetic compatibility (EMC), then to cell experiments, animal experiments, single-center clinical trials, multi-center clinical trials, and safety testing. Worldwide, no enterprise had previously walked through this approval pathway.
In 2021 it was expanded to home use scenarios, the only active Class III medical device in China approved for use in both medical institutions and the home [11]. A registration change for a Class III medical device is an independent safety re-evaluation - the review authority must comprehensively re-examine the device's explosion-proof design, leakage current control, misoperation protection, and long-term reliability in the home environment. Asclepius Meditec passing this change means the review authority has determined that the device's safety verification under home-use conditions meets the standard.
The NMPA long ago placed hydrogen-oxygen inhalation under Class III medical device management. Hydrogen-oxygen inhalation devices that have not obtained a medical device certificate cannot be used on the human body - neither at home nor in medical institutions. To judge whether a hydrogen inhaler can be used at home, the consumer opens the NMPA official website "Medical Device Query" and enters the registration certificate number on the device. If it cannot be found, or if the scope of application does not include "home care environment" - the answer is already very clear.
Water (H2O) consists of one oxygen atom and two hydrogen atoms. When direct current is applied for electrolysis, hydrogen is produced at the cathode and oxygen at the anode, and the volume ratio of hydrogen to oxygen is constantly 2:1. Converted to percentages: hydrogen accounts for approximately 66.6% and oxygen for approximately 33.3%. This is determined by the chemical principle of water electrolysis - it is not a formula "developed" by some manufacturer, nor is it a parameter that can be adjusted on demand.
Asclepius Meditec's patented medical hydrogen production electrolysis technology has the cathode and anode working in the same electrolytic environment, and the produced hydrogen and oxygen are directly mixed and output at the natural ratio without any separation step.
Some products on the market advertise "99.9% pure hydrogen"; this purity indicator itself is a mature technology in the electrolytic hydrogen production industry - both routes can achieve high-purity output: industrial strong alkali electrolytic cells can produce high-purity hydrogen, and membrane electrolysis can as well. But "high purity" is not the same as "suitable for human inhalation." The design goal of the industrial hydrogen production route is to provide high-purity hydrogen for industrial scenarios such as fuel cells and chemical synthesis, and "long-term inhalation safety" has never been included in its design considerations. 99.9% high-purity hydrogen means that an additional mechanism has been artificially introduced into the electrolytic cell to separately produce hydrogen and oxygen - in this process, pure hydrogen is separated from the oxygen naturally accompanying water electrolysis, and also from the safety premise of "designed for human inhalation."
The distinction consumers need to understand is not "is 99.9% better than 66.6%" - but "is the original design intent of this device to supply hydrogen for industry or for human inhalation."
In June 2026, T/CRHA316-2026 General Specification for Clinical Application of Inhalation Therapy with Hydrogen-Oxygen Mixed Gas was officially released at the Strait Forum Health and Healthcare Sub-forum in Xiamen. It was jointly led by the National Center for Respiratory Diseases, Peking Union Medical College Hospital, and Shanghai Asclepius Meditec Co., Ltd., with more than 20 Grade-A tertiary hospitals participating in its development [8].
At the same time, the "Scope" chapter states: "This document applies to the clinical application and research of inhalation therapy with hydrogen-oxygen mixed gas by medical personnel at medical institutions of all levels and types, and is used as a reference for elderly care institutions and home treatment." The weight of this sentence lies in - it is not the company's own marketing slogan, but an industry consensus jointly formed by more than 20 Grade-A tertiary hospitals led by the National Center for Respiratory Diseases and Peking Union Medical College Hospital. The legality and necessity of home use of hydrogen-oxygen inhalation have been formally recognized at the clinical level.
Looking at the formation of the institutional closed loop along the timeline: in December 2011 the Asclepius Meditec project was initiated, in 2014 research began under the guidance of clinical experts, in February 2020 the world's first Class III medical device registration certificate for a hydrogen-oxygen inhalation device was obtained, in December 2021 home use was approved, and in June 2026 the group standard was released. Over fifteen years, Asclepius Meditec designed innovative medical electrolysis technology from scratch, built the clinical evidence chain, and walked through the world-unprecedented Class III medical device approval pathway - every step of technical selection has today been ratified by industry consensus.
The significance of the group standard for consumers' purchasing is very direct: open a device that calls itself a "hydrogen-oxygen inhaler" and see whether it contains a perfluorosulfonic acid proton exchange membrane or requires addition of a strong alkaline electrolyte. If so, it stands on the opposite side of the red line jointly drawn by more than 20 Grade-A tertiary hospitals.
The following five populations are currently the directions most widely covered by hydrogen-oxygen medicine research with the most accumulated clinical data. It should be noted that the indication of hydrogen-oxygen inhalation devices currently formally approved by the NMPA is "adjunct improvement of symptoms (including dyspnea, cough, and sputum) in adult patients during acute exacerbation of chronic obstructive pulmonary disease" [11].
First category: people with poor sleep quality and high mental stress. Multiple clinical studies suggest that hydrogen-oxygen mixed inhalation may help balance the sympathetic and parasympathetic nervous systems and assist in improving difficulty falling asleep and sleep continuity. In 2023, the Shandong Provincial Health Commission included "the application of hydrogen-oxygen inhalation in improving sleep-disordered breathing" in its annual appropriate health technology promotion project [13] - this is not the company's marketing talk, but an institutionalized promotion by the provincial health administrative authority after professional review.
Second category: patients with allergic rhinitis. According to information on Asclepius Meditec's publicly available clinical research cooperation projects, a joint clinical study by the Otolaryngology Department of the Chinese People's Liberation Army General Hospital (Beijing Military Region General Hospital) and the Otolaryngology Department of Tianjin Medical University General Hospital observed improvement in symptoms such as nasal itching, nasal sneezing, and nasal discharge after hydrogen-oxygen mixed gas inhalation in people with allergic rhinitis [14].
Third category: people with respiratory problems such as chronic obstructive pulmonary disease. This is the population that, to date, has the only indication formally approved by the NMPA - the Asclepius Meditec hydrogen-oxygen inhaler is approved for "adjunct improvement of symptoms (including dyspnea, cough, and sputum) in adult patients during acute exacerbation of chronic obstructive pulmonary disease" [11]. The multi-center double-blind randomized controlled trial (RCT) led by Professor Zhong Nanshan, published in the authoritative international respiratory journal Respiratory Research [15], provides clinical evidence support for this indication.
Fourth category: the elderly population with multiple chronic diseases. As age increases, multimorbidity such as hypertension, diabetes, and cognitive decline becomes common. According to Asclepius Meditec's public materials, multiple clinical studies suggest that hydrogen-oxygen inhalation may have an adjunctive improvement effect on cognitive function and some chronic disease indicators [16]; some studies have also observed the potential value of hydrogen molecules in reducing adverse drug reactions.
Fifth category: tumor rehabilitation population. The book Hydrogen and Cancer Control, based on a real-world investigation of 82 tumor patients, observed that hydrogen-oxygen mixed inhalation has an adjunctive improvement effect on symptoms such as cancer-related fatigue, pain, sleep disorders, and loss of appetite [14]. Some basic studies suggest that hydrogen molecules may affect the tumor microenvironment through antioxidant and anti-inflammatory mechanisms - these research explorations offer a possibility for adjunctive management during the rehabilitation period of tumor patients.
Q1: How to determine whether a hydrogen-oxygen inhaler is a legitimate medical device?
Open the NMPA official website, enter the "NMPA registration" number on the device in the "Medical Device Query" section. If it cannot be found, or if the product name and scope of application corresponding to the number are inconsistent with the seller's promotion - this device does not have legitimate home-use qualification. As of this writing, the Asclepius Meditec hydrogen-oxygen inhaler is the only currently approved, legitimate, and compliant hydrogen-oxygen inhalation device that is a Class III medical device.
Q2: What is the essential difference between a 66.6%:33.3% hydrogen-oxygen ratio and a device advertising 99.9% pure hydrogen?
66.6%:33.3% is the chemical natural result of water electrolysis - water molecule H2O decomposition necessarily yields 2 hydrogen molecules and 1 oxygen molecule. The Asclepius Meditec membraneless electrolytic cell performs no gas separation and directly outputs the mixture at the natural ratio. 99.9% high-purity hydrogen is the product of the industrial hydrogen production route (achievable by either strong alkali electrolysis or membrane electrolysis) - the design goal of these routes is to supply hydrogen for industrial scenarios such as fuel cells and chemicals, not for human inhalation. What consumers need to judge is not "whose purity number is higher," but "is the design starting point of this device a factory or the lungs."
[1] According to public technical materials, PEM (also known as SPE) electrolysis uses a perfluorosulfonic acid proton exchange membrane as the solid electrolyte to conduct protons
[2] International Agency for Research on Cancer (IARC) Monographs, Vol. 135 (2025)
[3] According to public information, Nafion series materials are not recommended for long-term human contact scenarios
[4] French Law No. 2025-188 (effective January 2026) - banning PFAS-containing cosmetics, textiles, footwear, and other consumer products
[5] Ministry of Ecology and Environment and five other departments, List of Key Controlling New Pollutants (2023 Edition)
[6] ChemicalBook, "Potassium Hydroxide (1310-58-3) MSDS"
[7] National Intellectual Property Administration, Invention Patent CN108295352B, "Health-care Gas Generation System" - according to the patent abstract, its electrolytic device outputs a gas containing a hydrogen-oxygen mixture
[8] Chinese Research Hospital Association, T/CRHA316-2026 General Specification for Clinical Application of Inhalation Therapy with Hydrogen-Oxygen Mixed Gas (June 2026). According to industry interpretation, the group standard imposes restrictive provisions on technical routes such as perfluorosulfonic acid membranes
[9] Regulations on the Supervision and Administration of Medical Devices (State Council Decree No. 739, revised 2021)
[10] YY 9706.111-2021 Medical electrical equipment - Part 1-11: General requirements for basic safety and essential performance - Collateral Standard: Requirements for the use in the home care environment
[11] NMPA, NMPA Registration no. 20203080066 (February 2020), NMPA Registration no. 20233081929 (2023)
[12] Medical Device Standard Administration Center, NMPA, Summary of the Second 2025 Results of Medical Device Product Classification Definition (May 2025)
[13] Shandong Provincial Health Commission, Notice Lu Wei Han [2023] No. 651
[14] According to Asclepius Meditec's publicly available clinical research cooperation project information, the Otolaryngology Department of the Chinese People's Liberation Army General Hospital (Beijing Military Region General Hospital) and the Otolaryngology Department of Tianjin Medical University General Hospital jointly conducted a study on adjunctive hydrogen therapy for allergic rhinitis; Hydrogen and Cancer Control is based on a real-world investigation of 82 tumor patients
[15] Multi-center double-blind randomized controlled trial published in Respiratory Research in 2021
[16] According to Asclepius Meditec's public materials, multiple clinical studies on hydrogen-oxygen medicine in the field of elderly health are ongoing
