Hydrogen water or hydrogen-rich water (also called hydrogen-enriched water) simply means normal water (H2O) that contains dissolved hydrogen gas (H2). To put it briefly, hydrogen water is water with separate hydrogen molecules (H2) interspersed among the water molecules (H2O). This can be compared to carbon dioxide gas (CO2) being dissolved in carbonated water or carbonated beverages. In its natural state, regular water (tap water, seawater, river water, spring water, etc.) and the Earth's atmosphere below the troposphere generally do not contain separate hydrogen molecules (hydrogen gas, H2), except for some very rare instances.
For this reason, almost all hydrogen water is artificially created by humans. The majority of hydrogen water is produced through the electrolysis of water, where hydrogen gas (hydrogen molecules) is separated and reintroduced into water. This method ensures the production of safe and healthy water. Since the 2000s, various research findings in the medical field have revealed that hydrogen possesses antioxidant properties that can benefit human health. Consuming hydrogen water can potentially help reduce oxidative stress and inflammation in the body, which in turn may reduce the risk of certain diseases and improve overall health. Numerous research studies have highlighted these potential benefits.

Reactive oxygen species and the resulting oxidative stress are direct causes of aging and are associated with over 90% of all diseases. Toxic reactive oxygen species, specifically hydroxyl radicals, primarily induce oxidative stress, which is known to contribute to major lifestyle diseases such as cancer, dementia, diabetes, and hypertension.

Reactive oxygen species (ROS), also known as harmful oxygen, refer to oxygen that is in an unstable state and different from the oxygen we breathe. Excessive production of ROS occurs due to factors such as environmental pollution, chemicals, ultraviolet rays, circulatory disorders, and stress. Excess ROS in the body leads to oxidation. This process damages cell membranes, DNA, and other cellular structures, causing cells to lose function or undergo degeneration depending on the extent of the damage.

Hydrogen selectively removes the most harmful toxic reactive oxygen species, hydroxyl radicals, which were previously considered harmful to the body and had no removal or detoxification methods. Hydrogen does not react with beneficial reactive oxygen species that have beneficial effects on the human body. Moreover, hydrogen molecules, being the smallest in size, can quickly penetrate into the mitochondria within cells (hydrogen is 1/10,000 the size of mitochondria) to remove reactive oxygen species. It can also pass through the blood-brain barrier (BBB), which was previously inaccessible to conventional antioxidants, and remove reactive oxygen species that damage brain cells.