There are two critical issues with HW, 90%+ of the studies have had commercial or study methodological biases and that the PPM of hydrogen produced by devices is unregulated and inconsistent. I liken it more to snake oil then proven in any regard but time will tell as they do more meta research.
that particular study shows minimal effect in the antioxidant benefits compared to what could be optimized by 99.9999% of the population if people spent more time understanding nutrition.
The quote below comes from a pubmed article by the national library of medicine:
https://pmc.ncbi.nlm.nih.gov/articles/PMC10816294/"Also, it should be noted that, as some of the studies might have been supported by organizations with an interest in hydrogen-rich water products, there could be commercial biases in publication. A proper conflict of interest analysis is required as we move forward. Over the last few years, there has been a better understanding of the effects of hydrogen, with studies showing that the primary molecular target of hydrogen is Fe-porphyrin [49]. The main target of hydrogen intracellularly is mitochondria, where oxidized Fe-porphyrin has been shown to be responsible for hydrogen’s destruction of reactive oxygen species. Fe-porphyrin has also been shown to rectify electron flow in disordered states. Quantum biology going forward can help us better understand the exact mechanism of molecular hydrogen on mitochondria [50]. Hydrogen-rich water also leads to the activation of Nrf2, which has been shown to have a positive impact on cardiovascular health [1] and anti-aging effects [35]. We should look forward to developing therapeutic protocols and validating the potential of hydrogen-rich water in a clinical setting."