Hydrogen is the smallest and lightest atom found in nature. It is present, in minimal quantities, in the air we breathe and is one of the main elements that make up our body.
For a long time, it was considered an “inert” gas, that is, one with no relevant effect on health. In 2007, the journal Nature Medicine published the study that became a reference by identifying molecular hydrogen (H2) as an antioxidant with therapeutic potential.
Since then, research into the health benefits of molecular hydrogen has grown steadily. Today, with a growing number of scientific publications, molecular hydrogen is seen as an innovative therapeutic approach, although much of the evidence is still preliminary.
It is in the cells that health and its imbalances (diseases) make themselves felt. Many of these imbalances result from the dysregulation of a group or system of cells. Because of its small size, studies indicate that molecular hydrogen can easily diffuse into cells, reaching the nucleus and the mitochondria (the power stations of the cells).
So, could molecular hydrogen contribute to a healthier, more balanced life? In this article, we explain what it is, how it works, which benefits are being studied and what science already knows (and does not yet know) about it.
What is molecular hydrogen?
Molecular hydrogen exists as a gas. It is a molecule made up of two hydrogen atoms and is the smallest molecule found in nature.
Although hydrogen is one of the main constituents of living matter, in its gaseous form, as H2 (molecular hydrogen), it exists only in tiny concentrations in the air we breathe.
H2 can reach our body in several ways: through hydrogen water, inhalation devices, ampoules, and hydrogen-enriched creams or oils. Because it is such a small molecule, it can diffuse through cells and organelles, that is, the tiny “organs” of the cells. For this reason, researchers believe it may have a wide-ranging effect on cell functions.
Oxidative stress and inflammation: how molecular hydrogen works
Life, at cellular level, consists of thousands of processes in which countless substances are produced, transformed and broken down. One of the end results of these processes is the build-up of waste.
Free radicals (unstable and highly reactive molecules), also known as ROS (Reactive Oxygen Species), are among the main waste products of cell metabolism. When they are produced in excess, they become toxic and give rise to what is known as oxidative stress.
Oxidative stress is associated, alongside inflammation, with the development and chronic nature of many diseases. Inflammation is a normal part of the body’s defence against injury or infection. However, according to the NIEHS, when it fails to resolve and becomes chronic, it can contribute to further tissue damage and disease.
Two of the main actions attributed to molecular hydrogen (H2) are precisely its antioxidant action, which helps to combat oxidative stress, and its anti-inflammatory action. For this reason, it is being studied as a possible aid to the regulation of cell functions, in other words, to cellular health.
What are the health benefits of molecular hydrogen?
Since oxidative stress and long-term inflammation are associated with many chronic diseases, any substance that helps to control them may be of interest in the prevention and management of these diseases. This is the profile that research has been building up for molecular hydrogen.
In addition, molecular hydrogen appears to have other actions at cellular level, which explains the growing interest in its possible health benefits.
Studies on molecular hydrogen, carried out mainly in cell and animal models and, to a lesser extent, in small clinical trials, suggest the following main actions:
- antioxidant;
- anti-inflammatory;
- anti-allergic;
- stimulation of energy metabolism;
- regulation of gene transcription;
- modulation of programmed cell death (of interest for cancer research);
- signalling of dozens of cellular processes, such as immune and cell repair processes;
- possible support in recovery from surgical or traumatic injuries or those associated with radiotherapy and chemotherapy, also being studied in neurodegenerative, cardiovascular and oncological diseases;
- possible relevance to research on ageing, still at a preliminary stage.
Why is molecular hydrogen described as a selective antioxidant?
Free radicals are not only harmful: they also have useful functions, for example in fighting infections. Molecular hydrogen is one of the antioxidants that penetrates cells most easily, owing to its tiny size.
According to the study published in 2007 in Nature Medicine, it also has a selective antioxidant action, that is, it acts mainly on the most toxic free radicals, such as the hydroxyl radical, without interfering with those that perform important functions in the body. This is a characteristic that sets it apart from many other antioxidants.
Its easy diffusion into tissues also stands out. Studies indicate that it can cross the blood-brain barrier, which opens up the possibility of helping to protect the brain and central nervous system from oxidative stress and inflammation.
For these reasons, molecular hydrogen is described in the scientific literature as a facilitator and signaller of numerous cellular processes, which may help to optimise cell functions and regulate health-related processes.
In which diseases has molecular hydrogen been studied?
Preliminary studies suggest potentially beneficial effects in a wide variety of conditions, including:
- rheumatic diseases and autoimmune diseases;
- cardiovascular diseases and high blood pressure;
- diabetes;
- psychological wellbeing, notably anxiety and mood.
Possible benefits have also been described in a healthy body, such as better general wellbeing and cognitive function, and support for sports performance. A 2023 meta-analysis concluded that molecular hydrogen may reduce fatigue during exercise in healthy adults, but does not improve aerobic capacity. You can learn more about this topic in our article on the benefits of hydrogen water in sport.
What does research say about molecular hydrogen?
Scientific research on molecular hydrogen has grown remarkably, exploring its role as both a preventive and a therapeutic agent. The results obtained so far are promising.
Even so, it is important to read them with caution: most studies have been carried out in cells or animals, and clinical trials in humans generally involve few participants and short periods. Research is still limited, and larger studies are needed to confirm these benefits and to define the most appropriate indications, doses and forms of use.
Therapeutic applications of molecular hydrogen: forms of use
Molecular hydrogen has been studied through several routes of contact with the body:
- hydrogen inhalation at low concentrations;
- drinking hydrogen water (hydrogen-enriched water);
- application to the skin, through hydrogen-enriched creams or oils;
- application to the eyes, through hydrogen-enriched eye drops;
- direct, targeted application in a hospital setting, such as hydrogen-enriched saline solution given by injection.
The therapeutic applications being studied are therefore very varied. Some are highly specific and reserved for the hospital setting, notably in serious infections and injuries, surgery and transplants.
Molecular hydrogen inhalation
Inhalation of molecular hydrogen gas, at low concentrations, is carried out through nasal cannulas connected to devices that produce it. This route has been studied mainly in clinical settings, for example in myocardial infarction and ischaemic stroke, in trials that are still small.
Results in humans are still limited: in a trial with 20 patients with Parkinson’s disease, inhalation for four weeks showed no benefit. In addition, hydrogen gas is flammable at certain concentrations. Inhalation should be carried out with suitable equipment and, ideally, under the guidance of a health professional.
Molecular hydrogen for the skin
Applying H2 to the skin, in creams, oils or a hydrogen-enriched face mask, has been studied for skin health. The areas investigated, mainly in animal models, include skin damage caused by ultraviolet radiation, burns, pressure ulcers, psoriasis and atopic dermatitis.
Hydrogen water: the most accessible way to take molecular hydrogen
In the available studies, largely carried out in animals, drinking hydrogen water has been associated with the properties already mentioned: antioxidant and anti-inflammatory actions, regulation of the expression of various genes, stimulation of energy metabolism and protection against programmed cell death, among others.
Hydrogen water is water enriched with hydrogen gas in its molecular form, that is, H2. It is produced with a water hydrogenator, a device with filters that purify the water and a system that produces molecular hydrogen and releases it into the purified water.
Because the molecule of this gas is tiny, it diffuses rapidly into tissues and cells. In studies in rats, after hydrogen-saturated water was placed in the stomach, H2 was detected in the blood and accumulated in the liver.
As the most widely used and most accessible route, hydrogen water is considered safe and well tolerated in the studies carried out to date: a 2023 review of clinical studies found very few adverse reactions in humans. For this reason, it can be a worthwhile addition to your daily routine, as part of a balanced diet, good hydration and a healthy lifestyle. Find out more about the benefits of hydrogen water for hydration.
H2 tends to escape from water over time, especially once the container has been opened. It is therefore best to drink the water soon after preparing it, or to carry it in a full, tightly closed container to work, to your training session or to school exams.
Preliminary studies link drinking hydrogen water to improvements in mood and anxiety in daily life, seen in a small trial with 26 healthy adults, and to less fatigue during exercise. If you spend a lot of time away from home, a portable hydrogenator lets you prepare the water on the spot.
When should you talk to your doctor?
Molecular hydrogen does not replace medical diagnosis or treatment. If you have a chronic disease, take medication regularly, are pregnant or breastfeeding, or are considering hydrogen inhalation, talk to your doctor before making it part of your routine. Do not stop or change any treatment without professional advice.
Frequently asked questions about molecular hydrogen
What is molecular hydrogen and what is it used for?
Molecular hydrogen (H2) is a gas made up of two hydrogen atoms. It is studied mainly for its selective antioxidant and anti-inflammatory action, with possible interest in the prevention and management of several chronic diseases and in general wellbeing.
Are the benefits of molecular hydrogen proven?
The results are promising, but the evidence is still preliminary. Most studies have been carried out in cells or animals, and human trials are generally small. Larger studies are needed to confirm the benefits.
Is hydrogen water safe?
In the studies carried out to date, hydrogen water has been considered safe and well tolerated, with no relevant side effects reported. Even so, if you have an illness or take regular medication, you should consult your doctor.
Can hydrogen water replace medication?
No. Hydrogen water can complement a healthy lifestyle, but it does not replace medicines or prescribed treatments. Any change to your treatment should be discussed with your doctor.
Molecular hydrogen: a promising area for health
Molecular hydrogen is an innovative therapeutic approach with wide-ranging potential. It has been studied in several chronic diseases associated with the Western lifestyle, such as coronary heart disease, obesity, high blood pressure, type 2 diabetes, neurodegenerative diseases, autoimmune diseases, cancer and osteoporosis.
In healthy people, studies suggest possible benefits for cognitive performance, anxiety and mood, as well as for intense physical activity. It may therefore contribute to health, general wellbeing and quality of life.
The results obtained so far indicate that the properties of molecular hydrogen go beyond its antioxidant action, which has led researchers to describe it as a regulator of several biological processes. Even so, research in humans is limited, so it should be seen as a complement to healthy habits and medical follow-up.
As the simplest and safest way to take in H2 is through hydrogen water, why not consider it as a daily complement to a healthy lifestyle? Discover Filtrarte’s hydrogen water solutions and our home water purification solutions.
Curious about the potential of molecular hydrogen? Share this article and find out more about this area of health research.
Addendum: potential benefits of molecular hydrogen under research
The following table summarises the areas in which molecular hydrogen has been researched, based mainly on the review by Ichihara and colleagues (2015), which analysed 321 original articles, and on the review of clinical studies by Johnsen and colleagues (2023). About three quarters of the articles analysed in the first review show effects in mice and rats, and human trials generally involve few participants. They should therefore be read as potential benefits under study and not as established therapeutic indications.
| Brain and Nervous System • Cognitive function: in a one-year trial in people with mild cognitive impairment, no overall difference compared with placebo (in humans) • Parkinson’s disease: positive results in animal models, but a trial with 178 patients showed no improvement • Alzheimer’s disease: results in animal models and in a study with only 8 patients • May aid recovery from ischaemic stroke (small trials in humans) • Neonatal cerebral hypoxia • Possible protection against neurotoxic substances • Head injuries and spinal cord injuries | Urinary System • Interstitial cystitis: in a human trial, no significant difference compared with placebo • Haemodialysis patients: lower blood pressure and inflammatory markers with H2-enriched dialysis solution (in humans) • May minimise the kidney toxicity of cisplatin (chemotherapy) • May minimise complications of kidney transplants |
| Heart • Myocardial infarction (including small trials in humans) • Heart transplant • Atherosclerosis • Heart damage caused by radiation | |
| Organ transplants • May minimise complications of heart, lung, intestine and kidney transplants | |
| Digestive system • Periodontitis (gum inflammation) • May relieve stomach damage caused by aspirin • Possible inhibition of intestinal inflammation and benefits in ulcerative colitis • Possible protection of the liver against damage caused by medicines such as paracetamol • Chronic hepatitis B and non-alcoholic steatohepatitis (fatty liver) • Possible benefits in acute pancreatitis • Possible benefits in intestinal transplantation Bones • Osteoporosis and bone loss | Psychological Condition • May improve mood and anxiety (small trial in healthy adults) • Lower sympathetic nerve activity at rest (in the same trial) |
| Eyes and Ears • Corneal chemical burns and protection of the cornea during cataract surgery (in humans) • Damage to the retina and optic nerve • Hearing loss • May minimise the toxicity of cisplatin to the ears | |
| Diabetes and Metabolic Syndrome • Type 2 diabetes: improvement in some glucose metabolism markers in small human studies • May improve the metabolism of “fats” in the blood • Reduced body fat in overweight people (small study) | Skin and Allergies • Atopic dermatitis and psoriasis • Type I allergy and asthma • May help to regulate immune and allergic responses |
| Lungs • Acute lung injury from various causes • Asthma and COPD (studies in humans) • Lung transplant | Cancer • In the laboratory: inhibition of tumour cell growth and of the formation of new blood vessels in tumours • Possible better tolerance of chemotherapy (CT) and radiotherapy (RT) (small studies in humans) |
| Healthy body • General wellbeing • Cognitive function • Mood support • Research on ageing (preliminary) | Chemotherapy • Less liver damage in patients with colorectal cancer (trial with 134 patients) • Fewer adverse events in patients with lung cancer • May relieve the kidney toxicity of cisplatin |
| Athletic performance • May reduce perceived fatigue during exercise • May reduce blood lactate during exercise • No proven improvement in aerobic capacity or endurance • Possible support in recovery from sports-related soft tissue injuries (small study) | Radiotherapy • Better quality of life during radiotherapy (trial with 49 patients with liver tumours) • Possible protection of the skin, heart, lungs and other tissues against radiation |
References
- Ohta, S. (2011). Recent progress toward hydrogen medicine: potential of molecular hydrogen for preventive and therapeutic applications. Current Pharmaceutical Design, 17(22), 2241-2252. doi: 10.2174/138161211797052664
- Ohta, S. (2012). Molecular hydrogen is a novel antioxidant to efficiently reduce oxidative stress with potential for the improvement of mitochondrial diseases. Biochimica et Biophysica Acta (BBA) – General Subjects, 1820(5), 586-594. doi: 10.1016/j.bbagen.2011.05.006
- Ohta, S. (2015). Molecular Hydrogen as a Novel Antioxidant: Overview of the Advantages of Hydrogen for Medical Applications. Methods in Enzymology, 555, 289-317. doi: 10.1016/bs.mie.2014.11.038
- Ohsawa, I., Ishikawa, M., Takahashi, K., Watanabe, M., Nishimaki, K., Yamagata, K., … & Ohta, S. (2007). Hydrogen acts as a therapeutic antioxidant by selectively reducing cytotoxic oxygen radicals. Nature Medicine, 13(6), 688-694. doi: 10.1038/nm1577
- Yang, M., Dong, Y., He, Q., Zhu, P., Zhuang, Q., Shen, J., … & Zhao, M. (2020). Hydrogen: a novel option in human disease treatment. Oxidative Medicine and Cellular Longevity, Volume 2020, Article ID 8384742, 17 pages. doi: 10.1155/2020/8384742
- Zhang, Y., Tan, S., Xu, J., & Wang, T. (2018). Hydrogen therapy in cardiovascular and metabolic diseases: from bench to bedside. Cellular Physiology and Biochemistry, 47(1), 1-10. doi: 10.1159/000489737
- Asada, R., Tazawa, K., Sato, S., & Miwa, N. (2020). Effects of hydrogen-rich water prepared by alternating-current-electrolysis on antioxidant activity, DNA oxidative injuries, and diabetes-related markers. Medical Gas Research, 10(3), 114. doi: 10.4103/2045-9912.296041
- Mizuno, K., Sasaki, A. T., Ebisu, K., Tajima, K., Kajimoto, O., Nojima, J., … & Watanabe, Y. (2017). Hydrogen-rich water for improvements of mood, anxiety, and autonomic nerve function in daily life. Medical gas research, 7(4), 247. doi: 10.4103/2045-9912.222448
- LeBaron, T. W., Laher, I., Kura, B., & Slezak, J. (2019). Hydrogen gas: from clinical medicine to an emerging ergogenic molecule for sports athletes. Canadian Journal of Physiology and Pharmacology, 97(9), 797-807. doi: 10.1139/cjpp-2019-0067
- Ostojic, S. M. (2015). Molecular hydrogen in sports medicine: new therapeutic perspectives. International Journal of Sports Medicine, 36(4), 273-279. doi: 10.1055/s-0034-1395509
- Ichihara, M., Sobue, S., Ito, M., Ito, M., Hirayama, M., & Ohno, K. (2015). Beneficial biological effects and the underlying mechanisms of molecular hydrogen: comprehensive review of 321 original articles. Medical Gas Research, 5, 12. doi: 10.1186/s13618-015-0035-1
- Johnsen, H. M., Hiorth, M., & Klaveness, J. (2023). Molecular hydrogen therapy: a review on clinical studies and outcomes. Molecules, 28(23), 7785. doi: 10.3390/molecules28237785
- Dhillon, G., Buddhavarapu, V., Grewal, H., Sharma, P., Verma, R. K., Munjal, R., Devadoss, R., & Kashyap, R. (2024). Hydrogen water: extra healthy or a hoax? A systematic review. International Journal of Molecular Sciences, 25(2), 973. doi: 10.3390/ijms25020973
- Zhou, K., Liu, M., Wang, Y., Liu, H., Manor, B., Bao, D., Zhang, L., & Zhou, J. (2023). Effects of molecular hydrogen supplementation on fatigue and aerobic capacity in healthy adults: a systematic review and meta-analysis. Frontiers in Nutrition, 10, 1094767. doi: 10.3389/fnut.2023.1094767
- National Institute of Environmental Health Sciences (NIEHS). Inflammation. Accessed September 2026. https://www.niehs.nih.gov/health/topics/conditions/inflammation
By the Filtrarte Expert Team
The information in this article is not intended to recommend any treatment for symptoms or diseases. Consult your doctor for specialist advice.
