Ionic water, often marketed as “ionized water” or “alkaline water,” is standard drinking water processed to modify its chemical properties, particularly its potential of hydrogen (pH) and electrical charge. This modification is typically achieved through a process that physically separates the water into two distinct streams. The goal of this processing is to create water with a higher pH level than neutral water for consumption. The term “ionic” refers to the altered balance of ions within the water.
How Electrolysis Creates Ionic Water
The mechanism used to produce ionic water is called electrolysis, which is carried out in a device often referred to as a water ionizer. This process requires a direct electrical current to be passed through the water. Inside the ionizer, the water flows over specialized electrodes, which conduct the electricity.
The electrical charge splits the water molecules, H₂O, and the dissolved mineral content into two separate streams. Water naturally contains hydrogen ions (H⁺) and hydroxide ions (OH⁻). The electric field attracts these charged particles to two different chambers separated by a membrane. The positive electrode, or anode, attracts the negatively charged hydroxide ions, while the negative electrode, or cathode, attracts the positively charged hydrogen ions.
At the cathode, where the alkaline water is collected, the concentration of hydroxide ions (OH⁻) increases, leading to a higher pH. At the anode, the concentration of hydrogen ions (H⁺) increases, resulting in a lower, more acidic pH. This physical separation via a membrane prevents the newly formed alkaline and acidic waters from mixing, allowing them to be dispensed through two distinct outlets.
Defining Alkaline and Acidic Water
The electrolysis process yields two distinct products: alkaline water and acidic water. The alkaline output is the stream intended for drinking, typically possessing a pH between 8.5 and 9.5. This high pH is the result of the increased concentration of hydroxide ions and alkaline minerals like calcium and magnesium that are naturally present in the source water.
The acidic water output, conversely, has a low pH, generally ranging from 4 to 6. This stream is characterized by a higher concentration of hydrogen ions. This acidic water is generally not intended for drinking, as high acidity can be corrosive and may affect dental enamel.
Instead, the acidic output is often marketed for external uses, such as cleaning, skin care, and sanitation, due to its mild antimicrobial properties. Therefore, “ionic water” serves as a blanket term encompassing both the higher pH, consumable alkaline stream and the lower pH, non-consumable acidic stream produced simultaneously.
Scientific Review of Health Claims
A major selling point for ionic water devices is the purported presence of antioxidant properties, which marketers link to a negative Oxidation-Reduction Potential (ORP). ORP is a measurement of the water’s ability to act as a reducing agent, meaning it can donate electrons to neutralize oxidizing agents or free radicals. Proponents claim a negative ORP in the alkaline water stream indicates antioxidant capacity that can combat oxidative stress in the body.
Despite these claims, large-scale, controlled, peer-reviewed human studies supporting the broad therapeutic use of alkaline ionic water are largely lacking or inconclusive. Common marketing assertions, such as improved hydration, detoxification, balancing the body’s pH, or acting as an anti-aging agent, have not been definitively substantiated by robust scientific evidence.
From a physiological standpoint, the human body maintains a tightly regulated blood pH within a very narrow range of 7.35 to 7.45 through complex buffering systems involving the kidneys and lungs. The ingestion of slightly alkaline water does not significantly alter this systemic pH balance. For this reason, major regulatory bodies, such as the U.S. Food and Drug Administration (FDA), have not endorsed the therapeutic health claims made by many manufacturers of water ionizers, often warning against false or misleading advertisements.