The short answer: electrolysis splits the water, and the base decides what happens to the byproducts
A current runs through two metal plates sitting in the water, inside a sealed base.
The Molecular Hydrogen Institute's electrolysis primer describes the two halves. At the negative plate, the cathode, hydrogen ions "are converted (reduced) to a hydrogen atoms" which "immediately reacts with another hydrogen atom to produce H2, molecular hydrogen gas." At the positive plate, the anode, hydroxide ions "are oxidized to form oxygen gas (O2)". And if the water carries chloride, as tap water often does, the same primer notes that chloride "will oxidize (instead of the OH- ions) and form chlorine gas, which will then react with the water to form hypochlorous acid."
The hydrogen dissolves into the surrounding water, which is the entire point of the device. Where the oxygen and the chlorine-side byproducts go next is what separates a well-built base from a cheap one. PUREPEBRIX's certification page lists "ozone and chlorine byproducts" as the things its membrane keeps out; Echo describes an oxygen vent port for the same job.
Cathode and anode reactions, and the chloride-to-chlorine side reaction, quoted from the Molecular Hydrogen Institute, "What is Electrolysis? A Short Guide" (molecularhydrogeninstitute.org/electrolysis/), read September 7, 2026. Byproduct venting per Echo Flask's product page ("PEM Protection - Oxygen Vent Port") and PUREPEBRIX's certifications page, read September 7, 2026.
SPE/PEM membranes: the layer that decides whether byproducts stay out of your water
A membrane written SPE or PEM sits between the two electrodes in the better-built bases. PUREPEBRIX spells the pair out on its certifications page: "a Solid Polymer Electrolyte (SPE) membrane paired with a Proton Exchange Membrane (PEM)."
What it does, in the makers' own words: PUREPEBRIX says the membrane "separates hydrogen from oxygen and ozone at the molecular level"; Echo says its PEM and oxygen port mean oxygen is "expelled through the port" and the membrane "prevents oxygen or contaminants from flowing back into the water." The chemistry reference behind both is simpler: put a membrane between the two compartments and the two waters stop mixing.
The plain-language test is whether the maker names the membrane at all. Among the four bottles we compared for this page, three do: Echo Flask lists an "Advanced Proton Exchange Membrane" alongside a 5-year warranty and up to 8 ppm; PUREPEBRIX states "SPE/PEM electrolysis"; Piurify prints "DuPont SPE/PEM Platinum-Coated Electrolysis" on its product page. The fourth, AquaFusion, names an electrolysis feature ("HydroCharge") and no membrane standard anywhere on its sales page.
A bottle that never names its membrane is not automatically unsafe. It is a bottle where the one design detail the other makers point to for keeping oxidizing byproducts out of the water goes unchecked, because the maker has not written it down.
Membrane descriptions quoted from PUREPEBRIX (purepebrix.com/pages/certifications), Echo Flask (echowater.com/products/echo-flask) and Piurify (piurify.com Hydrogenator Bottle page), read September 7, 2026. Our AquaFusion review's rival table has a narrower "Tech stated" row, naming SPE/PEM only for Echo Flask, with Piurify as "electrolysis" and PUREPEBRIX as "IHSA-certified"; that row was built from 2026 category guides collected Aug 30, 2026, while the three membrane phrases above were read on each maker's own page Sep 7, 2026. Mixing note per the Molecular Hydrogen Institute electrolysis guide. AquaFusion's page (get-aquafusion.com) was read the same day and contains no "SPE", "PEM", "ppm" or "ppb". Product-specific claims are each maker's own, not our measurement.
Ppm and ppb, decoded: the same number, a thousand-fold apart
Ppm is "parts per million." For dissolved hydrogen it is functionally the same unit as milligrams per liter, mg/L: the Molecular Hydrogen Institute writes that "1 ppm is about the same as 1 mg/L and they are often used interchangeably."
Ppb is "parts per billion," and 1,000 ppb equals 1 ppm. A label that reads "1,600 ppb" and one that reads "1.6 ppm" are printing the identical concentration in different units, which is worth knowing before comparing two bottles that happen to use different scales (Piurify prints ppb; Echo prints ppm).
Here is the number that makes the rest of this page matter: plain water, in contact with hydrogen gas at one atmosphere and 25°C, saturates at roughly 1.6 ppm. The Institute's own Henry's-law table gives 1.57 mg/L, "or about 1.6 ppm," and calls 1.6 mg/L the concentration "considered the concentration at saturation" for pure hydrogen at sea-level pressure.
So when a spec sheet claims 4 ppm, or 8 ppm, well past that ceiling, pressure is doing the work. The same reference states Henry's law plainly: "if the pressure of that gas increases, then the amount of that gas dissolved in the water also increases." The bottles that publish those higher figures also publish the pressure: Echo Flask's spec sheet lists "Pressure: Up to 60 PSI" and a "Pressure Release Valve"; PUREPEBRIX's FAQ explains that "a brief hissing sound can occur when pressure is released after a generation cycle." Once the lid is open, the Institute notes, the concentration "decreases until it is at equilibrium with the partial pressure of H2 in the atmosphere," which for hydrogen is effectively zero. The small drips some owners find under the base are related: Echo calls them "an occasional and expected result of oxygen being expelled through the port," and PUREPEBRIX says "a small amount of moisture may appear near the exhaust after use."
Unit equivalence, saturation figure, Henry's law and the equilibrium note quoted from the Molecular Hydrogen Institute, "Concentration and Solubility of H2" (molecularhydrogeninstitute.org), read September 7, 2026. Pressure, valve and drip statements quoted from Echo Flask's product page and PUREPEBRIX's H8000 FAQ, read September 7, 2026; specific ppm claims below are each maker's own.
Cycle time is not dose: what four 2026 bottles actually publish
If concentration is the number that matters, cycle time is the number that gets printed instead, because a countdown timer is easy marketing and a ppm figure requires a maker to commit to a testable claim.
| Bottle | Cycle time, as published | Claimed concentration, as published |
|---|---|---|
| AquaFusion (entry-price glass bottle) | 3 minutes ("In just 3-minutes the micro-bubble electrolysis will infuse your water with hydrogen") | No ppm or ppb published |
| Piurify Hydrogenator Bottle (mid-tier, SPE/PEM) | 5-minute mode and 10-minute mode | 2,500 ppb at 5 minutes; 4,000 ppb (about 4 ppm) at 10 minutes |
| Echo Flask (premium, PEM) | 10-minute cycle and 20-minute cycle | Up to 6 ppm at 10 minutes; up to 8 ppm at 20 minutes |
| PUREPEBRIX H8000 (certified, SPE/PEM) | "Selectable generation cycles"; minutes not printed on the product page | 8,000+ ppb (over 8 ppm) per its certifications page (H2 Analytics test, IHSA Certificate of Compliance) |
Read across the two right-hand columns and two things stand out. First, the same ten minutes is not the same dose: Piurify's 10-minute mode is published as 4,000 ppb (about 4 ppm), while Echo Flask's 10-minute cycle is published as up to 6 ppm. Second, minutes without a number tell you nothing: AquaFusion's 3-minute cycle pairs with no concentration at all, and PUREPEBRIX prints its concentration but leaves the minutes to the manual.
Within a single bottle, more time can mean more hydrogen. Echo's own spec sheet moves from up to 6 ppm at 10 minutes to up to 8 ppm at 20, and its H2 Analytics report describes "6.07 mg/L of dissolved hydrogen after a 10-minute cycle and up to 8.25 mg/L after 20 minutes." That is a curve for one bottle. It does not transfer to another bottle's timer, which is why a 3-minute cycle with no ppm tells you less than a 10-minute cycle with one.
Every figure in the table is quoted from the maker's own page, read September 7, 2026: AquaFusion's "HydroCharge Technology" panel and sales page (get-aquafusion.com); Piurify's Hydrogenator Bottle page (piurify.com); Echo Flask's Tech Specs (echowater.com); PUREPEBRIX's certifications page and H8000 page (purepebrix.com). None of these figures is a Wellness Bench measurement. Our AquaFusion review's rival column prints 8.1 ppm at a 20-minute cycle for PUREPEBRIX and about 4.1 ppm for Piurify; those came from 2026 category guides collected for the review, while the figures here come from each maker's own page read Sep 7, 2026, and PUREPEBRIX's own pages print 8,000+ ppb without naming the cycle minutes.
How long the hydrogen lasts: the clock starts when the lid opens
Molecular hydrogen is, in the Molecular Hydrogen Institute's words, "the smallest molecule in the universe," and it "will also be able to diffuse through all plastic and many other containers." It does not stay dissolved in an open container the way flavor or minerals do.
How fast it leaves depends on who you ask. The Institute gives a chemistry figure: "A 500 mL open container of dissolved hydrogen water has a half-life of about two hours," so water starting at 1.6 mg/L "would likely be around 0.8 mg/L after two hours," with the rate "directly affected primarily by temperature, agitation, and surface area." Piurify, a bottle maker, publishes a more conservative storage table: open container, "a few minutes"; sealed plastic bottle, "1-2 hours"; sealed aluminium or Mylar pouch, "3-5 hours"; vacuum-sealed container, "approx 24 hours"; hydrogen bottle with storage capability, "up to 6+ hours."
Cold and a closed lid both help. Piurify's advice is "Keep it cold! Storing your hydrogen water in the fridge helps slow down hydrogen loss," and its sealed rows outlast its open row by hours.
The timing rule that follows is simple and unglamorous: drink the water shortly after the cycle finishes. Piurify's FAQ says "within 20–30 minutes of infusion"; PUREPEBRIX says "drink the water soon after a generation cycle." Filling a bottle in the morning and sipping from it across the day defeats the concentration a cycle was designed to produce, regardless of what ppm that cycle claimed.
Half-life, temperature and diffusion statements quoted from the Molecular Hydrogen Institute, "Concentration and Solubility of H2," read September 7, 2026. Storage table and fridge advice quoted from Piurify, "How Long Does Hydrogen Water Last" (piurify.com blog); timing advice from Piurify's home-page FAQ and PUREPEBRIX's H8000 FAQ, all read September 7, 2026. The vendor figures are vendor-reported, not peer-reviewed measurements.
How to check a bottle at home: reagent drops, and what a reading actually confirms
Two ways exist to check a bottle's real concentration for yourself, rather than trust a spec sheet.
A colorless-endpoint titration: a reagent containing methylene blue and a colloidal platinum catalyst (MB-Pt) is added drop by drop to a measured water sample. Methylene blue reacts with dissolved hydrogen in the presence of platinum to form colorless leucomethylene blue, so the sample stays blue once the hydrogen is used up. In the peer-reviewed method itself, "if 20 ml of hydrogen water reduces one drop of the MB-Pt reagent, the concentration of dissolved hydrogen (DH) is 14.5 μmol/L or 0.03 mg/L." A consumer kit built on this method may calibrate its own drop-to-concentration ratio differently, so its own instructions are the number to read, not this one.
The underlying method is peer-reviewed: a 2012 paper in Medical Gas Research by Seo, Kurokawa and Sato describes the titration, names the reagent as "MB-Pt reagent (MiZ Company, Kanagawa, Japan)," and lists MiZ Company as the authors' affiliation.
Electrochemical meters give a direct digital reading without a color-matching step. The same 2012 paper describes them as "the more complex and expensive electrochemical method," and reports that the drop titration "performs as effectively" as that method.
Either method answers the same question: not "does the bottle turn on," but whether the water in front of you, right now, reached a concentration anywhere near what a study actually used.
What counts as "reached the studied dose" depends on which study you mean. The Molecular Hydrogen Institute summarizes the range as "0.5 mg/L to 1.6+ mg/L, with most studies using a concentration near 1.6 mg/L." A home reading only shows where your glass sits against whichever figure you are comparing it to, not whether that figure did anything measurable for you personally.
Reagent-drop mechanism, the 20 mL sample, the 0.03 mg/L per-drop figure, the meter comparison and the MiZ Company detail quoted from Seo T, Kurokawa R, Sato B, "A convenient method for determining the concentration of hydrogen in water: use of methylene blue with colloidal platinum," Medical Gas Research 2012;2:1, PMC3309943, PMID 22273079, read September 7, 2026. Study concentration range quoted from the Molecular Hydrogen Institute, "Concentration and Solubility of H2," read the same day. We did not verify any single consumer kit's own drop-to-ppm calibration, so none is printed above.
Spec-sheet checklist before you buy: five lines, and which ones get left blank
Five items belong on any hydrogen bottle's spec sheet. Of the four bottles we compared, one product page (Piurify's) prints all five. AquaFusion's prints three, the cycle time, the battery and the body materials, and leaves the two that matter most, concentration and membrane, blank.
Published ppm or ppb
A number, in writing, not a marketing name for the technology. Without it, nothing on the rest of the sheet is comparable to a study concentration.
Membrane standard
SPE or PEM, named explicitly, or absent. This is the detail the makers themselves point to for keeping byproducts out of the water.
Cycle time
Minutes per cycle, useful mainly as a comfort figure once a ppm number exists to pair it with.
Battery capacity
Stated in mAh (AquaFusion: 1000 mAh; Piurify: 1,800 mAh; Echo prints "up to 7 cycles" per charge instead). A real spec, though it tells you about recharge frequency, not water chemistry.
Body material
Glass body with a stainless lid (AquaFusion), PPSU plastic (Echo Flask), food-grade polycarbonate (Piurify): a build detail worth knowing, not a hydrogen-dose detail.
A full checklist does not turn a bottle into a studied dose
Even a bottle that publishes all five items has told you what it delivers, not that delivering it produces any measured effect.
- A published ppm lets you compare a bottle to the 0.5 to 1.6+ mg/L range the Molecular Hydrogen Institute reports for studies. It is not evidence that any study used that bottle.
- A named membrane standard describes a design choice. It is not independent lab verification of any single unit.
- None of the five checklist items is a health claim, and none of them should be read as one.
Checklist status per each maker's own product page, read September 7, 2026: Piurify (ppb, SPE/PEM, 5- and 10-minute modes, 1,800 mAh, food-grade PC); AquaFusion (3-minute panel, 1000 mAh, glass body and stainless steel lid; no ppm, no membrane); Echo Flask (ppm, PEM, 10- and 20-minute cycles, PPSU, battery given as cycles per charge); PUREPEBRIX (ppb and SPE/PEM on its certifications page, with minutes, materials and battery deferred to "current product documentation"). Study range from the Molecular Hydrogen Institute. Where our AquaFusion review's rival table names SPE/PEM for Echo Flask only, that row came from 2026 category guides collected Aug 30, 2026, not from the maker pages read here Sep 7, 2026.
Questions people also ask
How long does hydrogen water last after the cycle?
Dissolved hydrogen starts leaving the water as soon as it meets open air. The Molecular Hydrogen Institute puts the half-life of a 500 mL open container at about two hours at room temperature, from 1.6 mg/L to around 0.8 mg/L, with temperature, agitation and surface area setting the pace. Piurify, a bottle maker, is more conservative in its own storage table: an open container holds hydrogen for a few minutes, a sealed plastic bottle for 1 to 2 hours, a sealed pouch for 3 to 5 hours, and a hydrogen bottle with storage capability for up to 6 or more hours, with the fridge slowing the loss. The practical rule from the makers is to drink shortly after the cycle finishes, not to fill a bottle in the morning and sip from it all day.
What does ppm mean on a hydrogen water bottle?
Ppm stands for parts per million, and for dissolved hydrogen it is the same as milligrams per liter (mg/L). One ppm equals 1,000 ppb (parts per billion), so a bottle claiming 1,600 ppb and one claiming 1.6 ppm are printing the same number in different units. Plain water saturates with hydrogen gas at about 1.6 ppm at one atmosphere and 25 degrees Celsius. A claim above that figure comes from a bottle that pressurizes during its cycle (Echo Flask lists up to 60 PSI), because dissolved gas rises with pressure; it is not a number an open glass can hold.
Does a longer cycle mean more hydrogen?
Not across bottles. On the spec sheets we read, the same 10-minute cycle is published as 4,000 ppb (about 4 ppm) on the Piurify Hydrogenator Bottle and as up to 6 ppm on the Echo Flask, and AquaFusion pairs its 3-minute cycle with no concentration at all. Within a single bottle a longer cycle can raise the reading: Echo Flask lists up to 6 ppm at 10 minutes and up to 8 ppm at 20 minutes. Minutes only tell you something once the maker prints the ppm next to them.
Can a hydrogen bottle work with tap water?
It depends on the maker. Piurify's instructions say to fill the bottle with filtered or tap water. Echo says tap water can be used but that its unknown chemicals and minerals may shorten the flask's life. PUREPEBRIX generally does not recommend tap water unless boiled and filtered, because scale and chlorine can shorten the membrane's lifespan, and recommends purified, distilled or mineral water instead. Electrolysis itself needs some dissolved minerals to conduct, so the tap-water question is about electrode and membrane wear, not about whether the reaction happens.
How we built this page
This is a mechanism explainer, built from named references, not a lab test of any single bottle. Every number on it is quoted from the source named next to it, all read on September 7, 2026.
- The electrolysis description, including the chloride-to-chlorine side reaction and the membrane note, is quoted from the Molecular Hydrogen Institute's "What is Electrolysis? A Short Guide."
- The 1.6 ppm saturation figure, the 1 ppm = 1 mg/L equivalence, Henry's law, the two-hour half-life and the 0.5 to 1.6+ mg/L study range are quoted from the Institute's "Concentration and Solubility of H2."
- The methylene blue test method, including the 20 mL sample, the 0.03 mg/L per-drop figure and the MiZ Company reagent, is quoted from Seo, Kurokawa and Sato, Medical Gas Research 2012 (PMC3309943, PMID 22273079). We did not verify any consumer kit's own calibration.
- Cycle times, concentrations, membranes, batteries and materials for the four named bottles are quoted from each maker's own product, certification or FAQ page: get-aquafusion.com (plus its "HydroCharge Technology" 3-minute panel), piurify.com, echowater.com and purepebrix.com. Hydrogen-retention times are Piurify's published storage table. No third-party buying guide is used as a source, and we did not measure any bottle's output.
- Nothing here is medical advice. A new supplement or wellness device while pregnant, nursing, or managing any condition is a conversation with a doctor first.
Where we ran this exact checklist against a real spec sheet
A checklist is easiest to trust once it has been run against something you can actually buy, line by line, with the blanks left visible.
We took the five-item spec-sheet checklist above and applied it to one real product: a glass-and-stainless bottle with a published cycle time and battery capacity, and a blank where the ppm line should be.
Read the ppm line before the price line. A published concentration, even a modest one, is more checkable than a marketing name for the electrolysis technology.
Check whether the cycle time is paired with a concentration, or standing alone. A minute count with no ppm next to it is a comfort feature, how long you wait, not a dose.
Affiliate disclosure: the review linked below contains affiliate links, and a purchase made through them may earn us a commission at no extra cost to you. This page carries no affiliate link of its own.
Read our AquaFusion reviewA 3-minute cycle, a 1000 mAh battery, a glass body with a stainless steel lid, and no ppm anywhere on its spec sheet.