What's Actually in Hydrogen Tablets? Magnesium, Malic Acid and Tartaric Acid Explained

A Hydrion H2 tablet lists exactly three ingredients: elemental magnesium, malic acid, and tartaric acid, alongside the 80 mg magnesium figure the product page highlights up front. None of the three is a passive filler; each one plays a specific role in what happens the moment the tablet touches water. This article works through what each ingredient does, why it has to be there chemically, and how to carry that same reading skill over to any other hydrogen tablet's ingredient list.

Before going ingredient by ingredient, here is what the label tells you and what it does not:

• The magnesium is the part that actually reacts. It donates electrons to the surrounding water and acid, and that transfer is what releases hydrogen gas.
• Malic acid and tartaric acid are common fruit acids that regulate how quickly the tablet dissolves and reacts; they are not a second "active" ingredient alongside the magnesium.
• The 80 mg of magnesium is what is left over once the reaction happens, not a measured supplement dose designed to be taken on its own.
• The same three questions used here, about the reactive metal, the acids that control the reaction, and what is stated as absent, apply when comparing any hydrogen tablet on the market.

What's actually on a Hydrion H2 tablet label

The Hydrion H2 tablet listing states that each tablet is built around three ingredients: elemental magnesium at 80 mg, malic acid, and tartaric acid. Dropped into 500 ml of water, the tablet is described as reaching 8 ppm of dissolved hydrogen within two to three minutes. The same listing also states that the tablets carry no added sugar, artificial sweeteners, preservatives or heavy metals. That short exclusion list matters here almost as much as what is included, since a hydrogen tablet's whole job is to react cleanly rather than to flavor or preserve anything.

Each of the next two sections takes one part of that list and explains the chemistry behind it, starting with the ingredient that does the actual work.

Why magnesium is the ingredient that makes hydrogen

Magnesium sits high on the reactivity series of metals, the ranking chemists use to describe how readily a metal gives up electrons when it meets water or an acid (source: Magnesium, Wikipedia). That willingness to give up electrons is the whole mechanism: when the tablet's magnesium contacts water and the acids in the tablet, it loses electrons to hydrogen ions in the solution, and those hydrogen ions combine into hydrogen gas (H2). The magnesium itself does not disappear from the water. It reforms as magnesium hydroxide or dissolved magnesium ions, the same chemical form magnesium takes in ordinary mineral water (source: Magnesium, Wikipedia).

The general pattern: metal plus acid gives a salt plus hydrogen gas

This is not specific to hydrogen tablets. Any metal positioned above hydrogen on the reactivity series follows the same general reaction when it meets an acid: metal plus acid produces a salt plus hydrogen gas (source: Oxidation-Reduction Reactions, Chemistry LibreTexts). A hydrogen tablet is a compact, food-safe application of that same reaction: the magnesium is the reactive metal, and the malic and tartaric acids supply the acidic environment that keeps the reaction going once the tablet is in water.

Why the tablet also contains malic and tartaric acid

Malic acid and tartaric acid do not add hydrogen to the reaction on their own; their job is to control how fast the magnesium reacts once the tablet hits water, so it dissolves and releases its hydrogen within the two-to-three-minute window the product describes rather than fizzing instantly or barely reacting at all. Both acids are familiar outside of hydrogen tablets. Malic acid is the dominant acid in apples and several other fruits, and it is an approved food additive, E296 in the EU, used across the food industry to add tartness and regulate acidity (source: Malic acid, Wikipedia). Tartaric acid plays a similar role and is best known as the main acid in grapes, where it is also approved as a food additive, E334, for its sour taste and its function as an antioxidant in food processing (source: Tartaric acid, Wikipedia). Seeing "acid" on a hydrogen tablet label can read as alarming if you do not know what it refers to, but in this case it means two acids that already show up naturally in the fruit you might eat with breakfast.

How much magnesium you're actually getting

The 80 mg of magnesium on the label is worth putting next to a general reference point rather than treating as a number that needs its own decision. UK NHS guidance puts adult dietary magnesium needs at roughly 300 mg a day for men and 270 mg a day for women aged 19 to 64, and describes total magnesium intake of 400 mg or less a day, including from supplements, as unlikely to cause harm for most people (source: Vitamins and minerals: Others, NHS). Measured against that range, one tablet's 80 mg is a modest fraction of a typical day's intake, and it is worth remembering that this magnesium is a byproduct of the reaction that makes the hydrogen, not a supplement dose formulated to hit a specific target. Anyone managing magnesium intake for a medical reason should factor it in and raise it with a clinician rather than working it out from a product label alone.

A label-reading checklist for any hydrogen tablet

Once you understand why each ingredient on the Hydrion H2 label is there, the same four checks carry over to any hydrogen tablet you are comparing it against:

• Identify the reactive metal and how much of it is listed per tablet, since that is the ingredient actually generating the hydrogen.
• Look at which acids or other excipients are listed, and whether they read as recognizable food-grade ingredients rather than unfamiliar chemical names.
• Check the stated hydrogen concentration together with the volume of water and the time it is measured over, since a ppm figure means little without those two numbers attached.
• Note what the label states is left out, such as added sugar, artificial sweeteners or preservatives, since that tells you almost as much about the product as what is included.

What an ingredient list doesn't tell you

Reading the label carefully answers what the tablet is made of and why, but it stops there on purpose. It does not tell you how much hydrogen actually ends up in your glass by the time you drink it, since that depends on timing and the container, a topic covered in more detail in a closer look at what the tablets' ppm figure actually means. It is also not a substitute for the dosage and timing guidance that belongs with the product rather than with its ingredient list; the existing guide to how the tablets work, dosage, and when to use them covers that ground directly. And a short, recognizable ingredient list is a characteristic of the label, not evidence of a health outcome on its own. Readers who want the broader picture on molecular hydrogen itself can start with what molecular hydrogen (H2) actually is, and anyone weighing safety questions can see how they are addressed in the separate look at hydrogen water safety, side effects, and myths.