This guide is written by Echo Water. Echo sells hydrogen water bottles and machines, and also a magnesium-based hydrogen drink mix in stick packs, so we sell two of the three formats compared here, though not cans. We've tried to be fair to all three. The science links go to Hydrogen Studies, a research database that Echo Technologies also funds. It reports null results alongside positive ones.
Short answer: all three can put real hydrogen in your glass, and in each case the level falls once the water meets air, so the concentration when you drink matters more than the number on the label. Tablets are cheap to start and easy to carry, but they add magnesium with every dose, about 12 mg for each milligram of hydrogen. Ready-to-drink cans need no preparation, but you pay per serving and keep buying. A bottle costs the most up front, adds nothing to the water and becomes the cheapest per liter if you use it daily. None of the formats has been shown to do more for your health than another.
How each format makes hydrogen water
- Tablets (and magnesium-based powders and sticks) contain magnesium metal, usually with organic acids. Dropped into water, the magnesium reacts and releases hydrogen gas: Mg + 2H₂O → Mg(OH)₂ + H₂. Some of the hydrogen dissolves; all of the magnesium stays in the drink.
- Cans and pouches are filled at a factory, where hydrogen is dissolved into water under pressure and the container is sealed. Aluminum holds hydrogen far better than glass or plastic.
- Bottles and machines use electrolysis: an electric current splits water, and the hydrogen dissolves into the water you drink. Nothing is added to the water, and the output depends on the device, the water and how clean the electrodes are.
For a fuller explainer, see what is hydrogen water? and our guide to how a hydrogen water bottle works.
ppm when you actually drink it
Water at normal pressure and room temperature holds only about 1.6 ppm of hydrogen (1.6 mg per liter). Every format can briefly go higher, and every format drifts back down once it's open.
| Format | What's been measured | What happens next |
|---|---|---|
| Magnesium tablet | About 10 mg/L right after a tablet dissolved in an open beaker | Fell to about 1.6 mg/L within 30 minutes |
| Can or pouch | At least 4.66 mg/L in one trial's containers; lab-made pressure bottles held about 7–10 ppm for up to a week while sealed | Fell within 1–2 hours of opening |
| Electrolysis bottle (Echo Flask) | 6.07 mg/L after a 10-minute cycle and 8.25 mg/L after 20 minutes, measured as the cap came off (H2 Analytics report H2AR-250116-1) | Starts falling once opened. In one trial, water went from 5.4 to 4.2 mg/L in the hour after opening. |
These figures come from different studies and methods, so they aren't a head-to-head test. The tablet and can figures are from Hydrogen Studies' tablets guide and ppm guide. Two practical lessons hold for every format: drink it promptly, and keep it in a closed container until you do. Hydrogen passes through plastic and glass walls, and in Japanese consumer tests, two products sold in plastic bottles had no detectable hydrogen at all.
Higher isn't proof of better, either. Human trials have used roughly 0.5 to 15 ppm, and none has identified a best or minimum concentration (see how much hydrogen water per day).
Magnesium: the tablet trade-off
Making hydrogen from magnesium uses up one magnesium atom for every hydrogen molecule, which works out to about 12 mg of magnesium for each milligram of hydrogen. One tablet described in a trial contained 80 mg of magnesium. For adults, the upper limit for magnesium from supplements and medicines is 350 mg a day, and food doesn't count toward it.
| Tablets a day (80 mg magnesium each) | Magnesium | Share of the 350 mg adult limit |
|---|---|---|
| 1 | 80 mg | 23% |
| 2 | 160 mg | 46% |
| 3 | 240 mg | 69% |
| 4 | 320 mg | 91% |
Products differ, so use the number on your label, and count magnesium from other supplements, antacids or laxatives too. The same arithmetic applies to Echo's hydrogen drink-mix sticks: Echo lists up to 5.65 mg of hydrogen per stick, which would take roughly 68 mg of magnesium to make if it all comes from the magnesium reaction.
In tablet trials, reported side effects were uncommon and mostly digestive, and in the largest trial they were about as common with placebo tablets that also contained magnesium. People with reduced kidney function, people taking certain medicines and children have the most reason to watch their magnesium. The details, including which medicines, are in hydrogen tablets: side effects and magnesium.
Cost per liter: how to compare
Tablets and cans are priced per serving, and a bottle is priced up front, so the only fair comparison is cost per liter at the amount you'll actually drink. Here's the arithmetic. The prices in the examples are round numbers for illustration, not any brand's actual price, so plug in the real ones you're comparing.
| Format | How to work out cost per liter | Example with made-up round numbers |
|---|---|---|
| Tablets or sticks | Price per tablet × tablets per liter | $1.00 a tablet, one per 500 mL: $2.00 per liter |
| Cans or pouches | Price per can ÷ liters per can | $3.00 for a 350 mL can: about $8.57 per liter |
| Electrolysis bottle | (Price + expected replacement parts) ÷ liters you'll drink over its life | $300 bottle, two 350 mL servings a day for three years (about 767 liters): about $0.39 per liter |
The pattern is predictable: the more often you drink hydrogen water, the more a reusable bottle pays off, and the less often you drink it, the more sense per-serving formats make. At one serving a week, a bottle could take years to catch up. Add in charging and cleaning time for a bottle, and shipping or storage for cans. If you're filling glasses for a whole household, a plumbed hydrogen water machine is another option to price the same way.
Convenience compared
- Tablets: small and light, with nothing to charge. You wait a few minutes for a tablet to dissolve, and trials had people drink it straight away.
- Cans or pouches: no preparation at all. They're heavier to carry and store, and each one is single-use packaging.
- Bottles: reusable, with no refills to buy. You need to charge the bottle, wait 10–20 minutes per cycle and descale it regularly.
Which format fits you
- Trying hydrogen water, or traveling: tablets or sticks cost little to start, as long as you count the magnesium.
- Occasional use with no preparation: cans or pouches, drunk soon after opening.
- Daily use without added minerals: a bottle. Check for a dated third-party lab report first; our hydrogen water bottle buyer's guide lists what to look for, and the Echo Flask is our option.
Whichever you choose, test it the same way: hydrogen reagent drops or a dedicated dissolved-hydrogen meter, at the moment you'd drink it. An ORP meter or pH strips can't measure hydrogen.
Frequently asked questions
Are hydrogen water tablets better than a hydrogen water bottle?
Neither has been shown to be better for your health. Tablets can reach high concentrations briefly and cost little to start, but they add magnesium. A bottle adds nothing to the water and costs less per liter with daily use, but it costs more up front and needs charging and cleaning.
How much magnesium is in hydrogen tablets?
It depends on the product, so check the label. One tablet described in a trial contained 80 mg. Making each milligram of hydrogen uses about 12 mg of magnesium, and the adult upper limit for supplemental magnesium is 350 mg a day. See hydrogen tablets: side effects and magnesium.
Do hydrogen water cans lose their hydrogen?
Sealed metal containers hold hydrogen well, but the level falls once you open them, within an hour or two in lab tests. Plastic and glass containers let hydrogen escape through their walls, even when sealed.
Which is cheapest per liter?
With daily use, usually a reusable bottle, because its cost is spread over hundreds of liters. With occasional use, tablets can work out cheaper overall. Work it out with your own prices using the formulas above.
The evidence behind this guide
- Hydrogen tablets: side effects, magnesium and what studies show
- Hydrogen water ppm levels
- What is hydrogen water?
- How much hydrogen water per day
- Hydrogen water side effects
Written by Echo Water. Last reviewed September 24, 2026. This is general information, not medical advice.