Hydrogen water vs. alkaline water: where's the difference?

Alkaline water (also: basic water) is water with a pH value above 7, typically between 8 and 9.5. It can be produced in various ways:

• Water ionisers: Electrolysis splits water into an acidic and an alkaline stream. The alkaline portion is consumed.
• Mineral additives: Minerals such as calcium, magnesium or bicarbonate are added to raise the pH value.
• Natural: Spring water can be naturally alkaline through contact with limestone (e.g. many Swiss mineral waters).

The central promise: Alkaline water is said to “de-acidify” the body and counteract an supposedly overly acidic environment. But more on that shortly.

Hydrogen water is water to which molecular hydrogen (H₂) is added – a colourless, odourless gas that acts as a selective antioxidant. Important: H₂ does not change the pH value of the water. It can have a neutral pH of 7 and still have an antioxidant effect.

It is produced by:

• Nanobubble technology: Tiny H₂ gas bubbles are introduced into the water under pressure (e.g. AWAKE)
• PEM electrolysis: Membrane separation produces pure H₂ without by-products
• Magnesium sticks: Magnesium reacts with water to form H₂ (lower concentration)

The scientific basis: more than 2,000 peer-reviewed studies and over 80 clinical human trials. More on this in our article Molecular hydrogen: what do the studies say?

Here lies the heart of the misunderstanding:

Crucial: A high pH value does not automatically mean a high H₂ content. Conversely, water with a neutral pH can have a high H₂ concentration. These are two independent parameters.

A review study published in 2022 (LeBaron et al., International Journal of Molecular Sciences) confirmed: “Molecular hydrogen is the exclusive active agent responsible for the therapeutic effects of electrolysed reduced water” – not the pH value.

The body of research on alkaline water is thin and contradictory:

• De-acidification: The body regulates its pH value extremely precisely via the lungs (CO₂ release) and the kidneys (bicarbonate buffering). Neither food nor water can appreciably change the blood pH value (7.35–7.45). A healthy kidney corrects slight fluctuations within minutes.
• Stomach acid: Stomach acid has a pH value of 1.5–3.5. Alkaline water is immediately neutralised in the stomach – the alkaline pH value never even reaches the intestine.
• No EFSA health claims: There are no authorised health-related claims for alkaline water in the EU/Switzerland.
• Isolated indications: Some studies suggest benefits for acid reflux (pH 8.8 inactivates pepsin in vitro), but the clinical relevance is unclear.

In summary: the “de-acidification” thesis has no solid scientific basis. This does not mean that alkaline water is harmful – there is simply little evidence for particular health benefits beyond plain hydration.

The research situation for molecular hydrogen is considerably more robust:

• Ohsawa et al. (2007), Nature Medicine: The pioneering study showed that H₂ acts as a selective antioxidant – it neutralises the hydroxyl radical (•OH), the most aggressive free radical, without affecting beneficial signalling molecules.
• Sim et al. (2020), Scientific Reports: A randomised, double-blind study in healthy adults showed reduced inflammatory markers and improved cell vitality after 4 weeks of H₂ water consumption.
• Aoki et al. (2012), Medical Gas Research: 42% less lactate accumulation in athletes – relevant for sport and recovery.
• FDA status: Molecular hydrogen is classified as GRAS (Generally Recognized As Safe).

Caveat: Many studies have small sample sizes and the research is still relatively young. Nevertheless, the evidence for H₂ is qualitatively and quantitatively stronger than for alkaline water. You can find more details in our overview of the studies.

Water ionisers are a particularly confusing topic because they produce both at the same time: alkaline water and dissolved hydrogen. For a long time the effects were attributed to the pH value – yet more recent research shows that the H₂ content is the decisive factor.

The aforementioned review by LeBaron et al. (2019) summarises:

• The therapeutic effects of electrolysed water correlate with the H₂ content, not with the pH value
• Studies using H₂ water at neutral pH show the same effects as studies using alkaline electrolysed water
• The pH value is a by-product of electrolysis, not the cause of the observed effects

Conclusion: If you own a water ioniser, you are probably already using H₂ – without knowing it. However, the H₂ concentration varies greatly between devices. Ready-to-drink products such as AWAKE offer a consistently high and measurable H₂ dosage (11+ ppm).

Here is an honest side-by-side comparison of both concepts:

Important: Neither concept replaces ordinary drinking water. Swiss tap water is among the best in the world and remains the foundation for your daily hydration.

Yes – and that is exactly what happens during electrolysis. Water ionisers produce water that is both alkaline and contains H₂. But: the two properties are independent of each other.

There are four possible combinations:

1. Neutral + no H₂ = ordinary tap water
2. Alkaline + no H₂ = e.g. water enriched with bicarbonate
3. Neutral + high H₂ content = e.g. AWAKE (11+ ppm, pH ~7)
4. Alkaline + H₂ = water from ionisers (variable H₂ concentration)

The research shows: only the variants containing H₂ (nos. 3 and 4) show the antioxidant effects described in the studies. The pH value alone makes no measurable difference.