“Negatively charged water” refers to water with a negative oxidation-reduction potential, or ORP, measured in millivolts. Regular tap water typically reads between +200 and +600 mV. Water with a negative ORP (below zero) contains dissolved hydrogen gas, which is the molecule responsible for pushing that reading into negative territory. There are several ways to produce it at home, each with different costs, effectiveness, and practical limitations.
What “Negatively Charged” Actually Means
ORP measures how readily water can donate or accept electrons. A positive ORP means the water tends to oxidize (accept electrons from) other substances. A negative ORP means it tends to donate electrons, acting as a reducing agent. For context, heavily chlorinated water can reach +650 to +950 mV, while electrolyzed water can drop to -400 mV or lower.
For years, the wellness industry attributed the negative charge to mysterious properties like “structured water” or “free electrons.” Research published in the International Journal of Molecular Sciences has since clarified that the negative ORP in electrolyzed water is completely explained by two factors: dissolved hydrogen gas concentration and pH. Remove the hydrogen gas, and the ORP goes positive. Bubble hydrogen gas into plain water, and the ORP goes negative. No exotic explanation is needed.
Method 1: Electric Water Ionizers
Water ionizers are countertop or under-sink devices that use electrolysis to split water at two electrodes. When voltage is applied, hydrogen gas forms at the negative electrode (cathode) and oxygen gas forms at the positive electrode (anode). The device separates the water into two streams: one alkaline and hydrogen-rich (negative ORP), the other acidic and oxygen-rich (positive ORP). You drink the alkaline stream and discard or repurpose the acidic one.
These machines typically produce water in the range of -200 to -600 mV, depending on the mineral content of your source water, flow rate, and power setting. They cost anywhere from $500 to $4,000. Source water needs some dissolved minerals for the electrolysis to work effectively. If you have very soft or reverse-osmosis filtered water, the machine will struggle to produce a strong negative ORP.
Method 2: Magnesium Sticks and Tablets
Metallic magnesium reacts with water to produce dissolved hydrogen gas and magnesium hydroxide. You can buy magnesium sticks (small mesh pouches of magnesium pellets) designed to sit in a water bottle. When magnesium powder or shavings are added to water, the ORP can drop to around -500 mV.
This method is far cheaper than an ionizer, typically $10 to $30 per stick, and each stick lasts several months before the magnesium is consumed by the reaction. The tradeoff is speed and control. You generally need to leave the stick in the water for 30 minutes to several hours, and the resulting water will be more alkaline and may have a slight mineral taste. The magnesium also slowly corrodes, so you’ll need to replace the stick periodically.
Method 3: Hydrogen Gas Tablets and Generators
Hydrogen tablets are effervescent tablets (usually containing metallic magnesium and an organic acid) that dissolve quickly in a sealed bottle, releasing hydrogen gas directly into the water. Because the container is sealed, more hydrogen stays dissolved rather than escaping into the air. These can produce a strong negative ORP in under two minutes.
Portable hydrogen generators are small battery-powered devices that electrolyze water inside a sealed bottle. They work on the same principle as a countertop ionizer but in a compact, single-serving format. Prices range from $50 to $300. Because these focus solely on dissolving hydrogen rather than also changing pH dramatically, they offer a more targeted approach.
Why Baking Soda Doesn’t Work
A common suggestion is to add baking soda to water to make it “negatively charged.” Baking soda does raise pH, making water more alkaline, but it does not dissolve hydrogen gas into the water. Since the negative ORP comes from dissolved hydrogen, not from alkalinity alone, baking soda will not meaningfully shift your water’s ORP into negative territory. You’ll get alkaline water, but not hydrogen-rich water. These are different things, despite often being conflated in marketing.
Storage and Shelf Life
Negatively charged water loses its properties quickly once exposed to air. Dissolved hydrogen gas escapes into the atmosphere the same way carbonation leaves an open soda. The negative ORP is, by nature, temporary. Once the hydrogen dissipates, the ORP climbs back toward positive values.
To preserve the effect as long as possible, store the water in a sealed container with minimal headspace (the air gap above the water line). Glass or aluminum bottles with tight seals work better than open cups. Drink the water within 30 minutes to a few hours of preparation for maximum hydrogen content. Refrigeration slows gas loss slightly, since cold water holds dissolved gases better than warm water.
What the Health Research Shows
The health interest in negatively charged water centers on dissolved molecular hydrogen acting as a selective antioxidant. In a pilot study of 20 people with risk factors for metabolic syndrome, drinking hydrogen-rich water for eight weeks produced a 39% increase in superoxide dismutase (an antioxidant enzyme the body makes naturally) and a 43% decrease in a key marker of cell membrane damage from oxidation. Participants also saw an 8% increase in HDL (“good”) cholesterol and a 13% improvement in their total cholesterol-to-HDL ratio by week four.
These are promising numbers from a small, open-label study, meaning participants knew what they were drinking. Larger, blinded trials are needed to confirm whether these effects hold up. The broader hydrogen water research field includes hundreds of studies in animals and smaller human trials across conditions ranging from exercise recovery to inflammation, but the evidence base is still developing. The effects appear modest and are tied specifically to the dissolved hydrogen, not to the ORP reading itself or to alkalinity.
Choosing the Right Method
- Best for convenience and speed: Hydrogen tablets in a sealed bottle. Fast, portable, and relatively inexpensive per serving.
- Best for continuous supply: A countertop water ionizer, if you want negatively charged water on tap and don’t mind the upfront cost.
- Best on a budget: A magnesium stick in a sealed water bottle. Cheap and simple, but slower and less precise.
- Best for controlled hydrogen concentration: A portable hydrogen generator, which lets you electrolyze water in a sealed environment without dramatically altering pH.
Whichever method you choose, the key variable is dissolved hydrogen, not the ORP number on a meter. A highly negative ORP reading driven mainly by high pH (rather than hydrogen content) won’t deliver the same properties. If you’re testing your water, measuring dissolved hydrogen directly (with a hydrogen meter or reagent drops) gives you more useful information than ORP alone, since pH heavily influences ORP readings and can make the number misleading.