"That is what the hydrogenated water is - just water " - No, it is not. H2O is a stable molecule, and the H2 is attached to the O. It's not a free form, and not available for the body as a molecule. You can dissolve any gas in the water. Dissolved Oxygen (O2) becomes oxygenated water. Dissolved Carbon dioxide (CO2), becomes carbonated water (soda). Dissolved Hydrogen gas becomes Hydrogenated water (H2) or also called Hydrogen-rich water.