H2 Library



Hydrogen is an element with one proton and one electron; it’s the simplest and smallest element in the known universe. Helium is created through the fusion of hydrogen. Hydrogen and helium together account for 99.9 % of all matter in the universe.

  • Hydrogen is the first element on the periodic table, with atomic number 1.
  • Hydrogen is present in water and in all organic compounds.
  • Hydrogen gas is colourless, odourless and tasteless.
  • Hydrogen gas is not flammable unless the temperature exceeds 527oC and the concentration in the air exceeds 4 % in volume.
  • When dissolved in water, hydrogen gas has a rating of 0/0/0 for health/flammability/instability on the Hazardous Material Information System.
  • Hydrogen gas has low water solubility, with the saturation concentration at normal conditions being around 1.6 ppm (1.6 mg H2 per litre).



“Have you ever wondered how the simplest and smallest element in the known universe could lead to a brighter, more intellectual, and healthier way of living?” (5)

In 1975, Dole et al. reported the possible application of hyperbaric hydrogen therapy in the treatment of cancer (6). More than 20 years later, Shirahata et al. (1997) reported a possibility of molecular hydrogen acting as a scavenger of reactive oxygen species (7). Another decade past, Ohsawa et al. (2007) reported in a prestigious medical journal, Nature Medicine, that molecular hydrogen might act as a selective antioxidant (8)

Since the landmark article of Ohsawa et al. (2007), more than 500 original and review articles on the potential therapeutic benefits of molecular hydrogen have been published in medical journals (9).



Selective Antioxidant

Molecular hydrogen is inert and, as mentioned above, is unlikely to react with ROS and RNS with low reactivity, which plays an important role in physiological functions as signalling molecules.

Short Residence Time

Owing to its small size, molecular hydrogen can quickly enter the bloodstream and diffuses into organs, tissues, cells and parts of the body where most antioxidants fail to reach. Similarly, molecular hydrogen is expelled in the breath as quickly as it enters the body. In the case of the study by Shimouchi et al. (2009), hydrogen water is taken orally appeared in the breath within 15 minutes and the concentration of molecular hydrogen in the breath returned to the basal level within 60 minutes (10). Unlike common drugs, the liver and the kidney are not involved in the metabolization of molecular hydrogen.


Use in Deep Diving

Hydrogen gas has safely been used in deep diving. The first report dates back to 1945 – by the Swedish engineer, Arne Zetterstrom. It was a mixture of oxygen and hydrogen gases, known as Hydrox. In late 1960’s, the United States Navy and the Compagnie Maritime d’Expertises of France also started testing the use of high-concentration hydrogen gas (up to 49%) in dives as deep as 700 m (11).

Endogenous Intestinal Gas

The health safety of molecular hydrogen has been discussed based on facts that the human gastrointestinal tract harbours trillions of microbes, namely the gut microbiota, and that molecular hydrogen is amongst the common biological gases produced by the gut microbiota – other common gasses being oxygen, nitrogen, carbon dioxide, methane and hydrogen. This is a long-accepted fact and constitutes the principle of the breath hydrogen test – a test to determine small intestinal bacterial overgrowth (121314).



  1. Ishibashi, T. et al., 2012. Consumption of water containing a high concentration of molecular hydrogen reduces oxidative stress and disease activity in patient with rheumatoid arthritis: an open-label pilot study. Medical Gas Research, 2: 27
  2. Sakai, T. et al., 2014. Consumption of water containing over 3.5 mg of dissolved hydrogen could improve vascular endothelial function. Vascular Health and Risk Management: 10: 591-597
  3. Ishibashi, T. et al., 2015. Improvement of psoriasis-associated arthritis and skin lesions by treatment with molecular hydrogen: A report of three cases. Molecular Medicine Reports, 12: 2757-2764
  4. Nicolson, G.L. et al., 2016. Clinical effects of hydrogen administration: From animal and human diseases to exercise medicine. International Journal of Clinical Medicine, 7: 32-76
  5. Dixon & Zhang, 2016. An Innovative collection in hydrogen molecular biology and medicine research. Medical Gas Research, 6: 55-56
  6. Dole, M. et al., 1975. Hyperbaric hydrogen therapy: a possible treatment for cancer. Science, 190: 152-154
  7. Shirahata, S. et al., 1997. Electrolyzed-reduced water scavenges active oxygen species and protects DNA from oxidative damage. Biochemical and Biophysical Research Communications. 234: 269-274. [link – PubMed]
  8. Ohsawa, M. et al., 2007. Hydrogen acts as a therapeutic antioxidant by selectively reducing cytotoxic oxygen radicals. Nature Medicine, 13: 688-694.
  9. Ge, L. et al., 2017. Molecular hydrogen a preventive and therapeutic medical gas for various diseases. Oncotarget, 8: 102653-102673.
  10. Shimouchi, A. et al., 2009. Breath hydrogen produced by ingestion of commercial hydrogen water and milk. Biomarker Insights, 4: 27-32.
  11. Abraini, J.H. et al., 1994. Psychophysiological reactions in humans during an open sea dive to 500 m with a hydrogen-helium-oxygen mixture. Journal of Applied Physiology, American Physiological Society, 76: 1113-1118.
  12. Newcomer, A.D. et al., 1975. Prospective comparison of indirect methods for detecting lactase deficiency. New England Journal of Medicine, 293: 1232-1236. [link – PubMed]
  13. Metz, G. et al., 1976. Breath-hydrogen test for small-intestinal bacterial colonisation. Lancet, 1: 668-669.
  14. Rhodes, J.M. et al., 1979. The lactulose hydrogen breath test as a diagnostic test for small-bowel bacterial overgrowth. Scandinavian Journal of Gastroenterology, 14:333-336.