Acid, base and dissolved hydrogen: three separate measures

Evidence status M3: pH describes the activity of hydrogen ions in a solution. Dissolved H₂ describes the amount of a gas in that same solution. These are two different physical quantities, and nothing about one follows from the other: a water can have a high pH and contain little dissolved hydrogen, and the reverse holds too. The comparison of the two water categories is carried by alkaline water and dissolved H₂ compared as measures.

Evidence status M3: Redox potential is given in millivolts and describes an electrochemical property of the solution. It is equivalent neither to pH nor to the content of dissolved hydrogen and cannot be converted into either of them. Reading three figures side by side therefore means reading three independent measurements, not three views of one thing. How these quantities arise technically is described in how the measurements arise technically. The wider frame is given by the overview of measurements and evidence levels.

Evidence status M3: The idea that the body as a whole is over-acidified and has to be balanced comes from everyday language and not from an endpoint definition in research. Physiologically, the pH of blood is regulated within very narrow limits, independently of what is being drunk. A beverage does not shift that regulation to a measurable outcome. This placement describes an everyday concept and explicitly makes no statement about diseases, symptom pictures or their treatment.

Not legally assertable: Questions about how a drink sits with someone and about complaints after drinking are symptom and safety questions. This article does not answer them, neither affirming nor advising against, and it derives no expectation about them from a measurement. The question is not dropped; it is visibly placed outside what this article covers. What the data record permits on safety questions overall, and where it ends, is placed in what the data record permits on safety.

Evidence status N: A robust statement about how one individual person takes up a particular drink would require a primary study with a defined population, a comparison group and a pre-specified endpoint. No such work is documented in this article. The systematic review (2024), International Journal of Molecular Sciences merely describes water with added molecular hydrogen as a product category of its own. Limit: it is a review, not a primary source, and it makes no recommendation. The gap therefore stays named and is not covered over with secondary literature.