How hydrogen tablets work: the chemistry inside every Aloha H₂ tab

1. What's actually inside a hydrogen tablet

Strip away the branding and every effervescent hydrogen tablet on the market is built from the same three functional parts:

• Elemental magnesium (Mg). This is the hydrogen source. Magnesium is a reactive metal that readily hands electrons to water molecules — and when it does, hydrogen gas is released. Tablets use a fine, high-purity, food-grade magnesium powder so the reaction is fast and complete.
• Food-grade organic acids. Typically malic acid and/or tartaric acid — the same acids found in apples and grapes. They do two jobs: speed up the magnesium reaction (acidic conditions strip away the passive oxide layer that would otherwise slow magnesium down) and neutralize the alkaline magnesium hydroxide byproduct so the finished water tastes neutral rather than chalky.
• Binders and flow agents. Small amounts of ingredients like dextrose or maltodextrin hold the pressed tablet together and control how quickly it breaks apart in water.

That's it. No hydrogen is "stored" in the tablet — the tablet generates hydrogen on demand when it meets water. This is why hydrogen tablets have a long shelf life (years, if kept dry) while pre-bottled hydrogen water loses potency within weeks.

2. The reaction, step by step

Drop an Aloha H₂ tab into 12–16 oz of water and here is what happens over the next two minutes:

1. 0–5 seconds: the tablet hits water and starts to break apart. The binders dissolve, exposing magnesium powder and acids to water simultaneously. Effervescence begins almost immediately.
2. 5–30 seconds: the acids activate the magnesium. Magnesium normally wears a thin oxide skin that slows its reaction with plain water. The organic acids dissolve that skin, exposing bare metal. The reaction accelerates sharply — this is when fizzing is most vigorous.
3. 30–90 seconds: hydrogen gas is produced. The primary reaction runs: Mg + 2H₂O → Mg(OH)₂ + H₂↑. Each magnesium atom releases one molecule of H₂. Millions of micro-bubbles form throughout the water, and a portion of that gas dissolves into the water itself.
4. 90–120 seconds: the reaction completes. The magnesium is consumed, fizzing slows, and the cloudiness begins to settle. The water now holds dissolved molecular hydrogen at or near its peak concentration.
5. After 2 minutes: the clock starts. H₂ is a gas and wants to leave the water. Concentration drops steadily from here — which is why the directions say to drink promptly.

3. Why the water turns cloudy (and why that's fine)

New users almost always ask about the cloud. Two things create it:

• Magnesium hydroxide, Mg(OH)₂. The solid byproduct of the reaction. It is only slightly soluble in water, so it forms a fine white suspension. Magnesium hydroxide is the active ingredient in milk of magnesia — it's about as benign as a mineral byproduct gets. The organic acids in the tablet convert most of it into soluble magnesium salts, which is why the cloud thins as the reaction finishes.
• Micro-bubbles of H₂. Freshly generated hydrogen forms bubbles so small they scatter light. As they coalesce and rise, the water clears.

Practical upshot: cloudy water at the 60-second mark is a sign the tablet is working. If you prefer a perfectly clear glass, wait an extra 30 seconds before drinking — but don't wait minutes, because the hydrogen leaves faster than the cloud does.

4. From gas bubbles to dissolved H₂ — what "PPM" measures

The bubbles you see are hydrogen gas that has already left the water. What your body absorbs is the hydrogen that is dissolved — individual H₂ molecules sitting between water molecules. That dissolved amount is what "PPM" (parts per million, equivalent to mg/L) measures.

Hydrogen's saturation limit in water at room temperature and normal pressure is about 1.6 ppm (1.6 mg/L). Effervescent tablets briefly exceed this because the reaction creates local supersaturation — the gas is generated faster than it can escape. That supersaturated peak decays quickly toward the 1.6 ppm ceiling and then below it. This is why a tablet's "peak PPM" number is only meaningful if the brand states when it was measured, in how much water, and whether the container was open or closed. Our Science page has a full guide to reading PPM claims.

Human trials that showed benefits typically used water in the 0.5–1.6 ppm range, consumed daily. One Aloha tab in 12–16 oz of water lands comfortably in that band when dissolved as directed.

5. Why timing matters so much

Molecular hydrogen is the smallest, lightest molecule that exists. It has almost no affinity for water — it's non-polar and doesn't form hydrogen bonds — so it slips out of solution at the first opportunity. Left in an open glass, dissolved H₂ falls by roughly half every 20–30 minutes, and by two hours most of it is gone.

That's why every credible hydrogen tablet brand gives the same instruction: dissolve, then drink within a few minutes. It's not a marketing quirk — it's physics. It also means:

• Don't pre-make hydrogen water in the morning for the afternoon.
• Don't stir vigorously or pour between glasses after dissolving — agitation drives gas out.
• Don't use hot water. Gas solubility drops as temperature rises, so hot water holds less H₂.

6. How to get the most H₂ per tablet

Same tablet, very different results depending on technique. Ranked from good to best:

1. Good — open glass. Drop the tab in 12–16 oz of room-temperature water, wait ~2 minutes, drink. You'll get a meaningful dose; some H₂ escapes during the reaction.
2. Better — closed plastic or glass bottle, small headspace. Fill a 16 oz bottle nearly to the top, drop the tab, cap it immediately. The trapped gas builds pressure, forcing more H₂ into solution. After 2 minutes, open and drink.
3. Best — closed bottle, pre-cooled water, drink within 5 minutes. Slightly cool water (not ice-cold, which slows the reaction) holds more dissolved gas. Cap, wait 2–3 minutes, drink promptly.

A few more practical notes:

• Avoid metal bottles for dissolving. Pressure build-up in a rigid metal container can be uncomfortable to open; a plastic bottle that flexes is safer. You can pour into a metal cup after dissolving if you like.
• Plain water works best. Sparkling water, juice, or coffee change the acid balance and the reaction rate. Stick to still water.
• Less water = higher concentration. 12 oz gives a higher ppm than 16 oz from the same tablet. Both are within the studied range.

7. Tablets vs. other ways to make hydrogen water

Magnesium tablets aren't the only route to hydrogen-rich water. The two other common formats work on completely different principles:

• Electrolysis machines and bottles pass an electric current through water, splitting H₂O into hydrogen and oxygen at electrodes. No magnesium is involved. Output depends on electrode quality, water mineral content, and run time. See our tablets vs. machines comparison.
• Pre-bottled hydrogen water is infused with H₂ under pressure at a factory and sealed in aluminum pouches or cans. Concentration decays from the moment it is filled, and glass or plastic bottles let hydrogen escape through the material itself.

Tablets win on portability, shelf life, cost per serving, and consistency — every tablet contains the same amount of magnesium, so every glass gets the same reaction. Machines win if you drink several liters a day at home and don't mind the upfront cost and maintenance.

8. FAQ

References

1. Ohta S. Molecular hydrogen as a preventive and therapeutic medical gas: initiation, development and potential of hydrogen medicine. Pharmacology & Therapeutics, 2014. PubMed
2. Ichihara M, Sobue S, Ito M, et al. Beneficial biological effects and the underlying mechanisms of molecular hydrogen — comprehensive review of 321 original articles. Medical Gas Research, 2015. PMC
3. Ohsawa I, Ishikawa M, Takahashi K, et al. Hydrogen acts as a therapeutic antioxidant by selectively reducing cytotoxic oxygen radicals. Nature Medicine, 2007. PubMed