Hydrogen water all the rage? The history, science, and verdict
For some time I’ve seen content online promoting “hydrogen water”. It never made much sense to me. Hydrogen is already present in water? Ever curious, I thought it was worth doing a deep dive to satisfy my curious mind. Here’s what I found.
Before we dig into hydrogen and other forms of water, we’ve gotta get through the basics. What is water?
Water (H20) is a molecule that’s made up of 3 atoms: 2 hydrogen atoms and 1 oxygen atom. I asked Dr Mike Todorovic his thoughts, he said:
“One oxygen atom with two hydrogen atoms attached either side in the shape of a boomerang. One of the reasons why water is so important is because it functions as our biological solvent (things dissolve in it). This is because the hydrogens have a slight positive charge and oxygens have a slight negative charge - making other charged molecules like sugar easy to dissolve.”
When each water molecule tightly clumps together it’s because of hydrogen bonding (the hydrogen sticking together). This bonding makes the water cohesive, but flexible. This is why it can take so many forms.
What is hydrogen water?
Hydrogen water, or more accurately, hydrogen-rich water, is water that has extra molecular hydrogen (H2) gas added to it. H2 has been reported to act as an antioxidant (and antioxidants are good because they neutralise free-radicals - but we actually don’t know a great deal about H2 effects in the body (Sim et al, 2020). The theory presented by those promoting the benefits of hydrogen water is that more antioxidants = less free radicals = better health. If only it were that simple! After digging into things a bit more, what I think proponents of hydrogen water are referring to is a hydrogen gas (H2) being infused into water (H20). But dissolving H2 into water is kind of like dissolving carbon dioxide; when you open the lid the gas will escape out. In any case, H2 (gas) is not present in the body in high amounts and is largely a product of metabolism - we fart and breathe that out!
A little background history - this trend is not new.
The interest in hydrogen-rich water, as far as I can tell, seems to have originated from Japan and the Kangen/Enagic water electrolysis company (and by company, I mean direct-selling/network marketing/multi-level marketing “selling freedom” scheme). Before that electrolysis was created for energy generation - ie hydroelectricity (Smolinka et al, 2022). From here, the evidence is pretty sketchy as to how we got to consumption of hydrogen-rich water…
Are electrolysed water and alkalised water the same?
Electrolysed water ≠ alkalised water. Electrolysis of water is a process to separate hydrogen from oxygen (aka break up the H20) by passing an electric current through the water- this creates energy (hydrogen). There are several different technologies available, the original of which is called alkaline water electrolysis. Water electrolysis’ main function is to create sterilising cleaning chemicals, hydrogen fuel and more. Whether the water becomes alkaline or acidic, or other aspects are filtered out (like fluoride), depends on what separator is used and if anything is added (like magnesium) (Amarasooriya et al, 2019) .
Electrolysis, put simply, is a technology that can be used to filter and disinfect water, or create energy.
What are the alleged benefits of hydrogen rich water?
Every website that sells variants of hydrogen water makes a myriad of claims. Here’s a quick snapshot of what I scanned online:
[Redacted Aussie company] claims “hydrogen water significantly improved heart health and prevented heart disease”...in mice. (As far as I can tell, mice aren’t humans)
[Redacted company] says “it’s a game changer for turbocharging your energy, ramping up your athletic performance…” and “slows down aging process” and “reduces inflammation”.
[Redacted company] “..proven to alleviate a range of conditions…as well as addressing conditions like cerebral infarction, Alzheimers disease..”
[redacted MLM company] reps claim “hydrogen water offers treatments for…diabetes, heart disease, cancer, kidney disease”
From a biochemistry perspective, these claims don’t make a great deal of sense. Here’s why.
Our body is made up of a lot of water. Our body also has a lot of hydrogen! And of course, hydrogen is an element of water. In the body, water is essential for carrying nutrients and wastes - this occurs via the blood, the digestive, and respiratory systems. The amount of hydrogen in the body is tightly controlled by the kidneys through the process of homeostasis (see a great explainer here).
What does the evidence say about hydrogen-rich water?
When the term hydrogen water was searched in PubMed, I found over 130,000 entries. You might be thinking “wow! That’s so much research”. Yeah, don’t be fooled. Once I filtered that for clinical trial or randomized controlled trial papers, it reduced the relevant articles to 802. When I changed the search term to “hydrogen-rich water” with the same filters, there were only 18 results. I also searched for systematic reviews on the topic (has someone else already filtered through the literature?). When I did this, I found that the majority of research on hydrogen-rich water (HRW) in humans is looking at sports science, dental hygiene, and blood stress profiles (Bai et al, 2023; Dhillon et al, 2024; Zhou et al, 2024). These studies all largely focused on biomechanical markers, and, importantly, did not explore HRW as a treatment for disease. In the handful of studies that did look at clinical treatment, there was a negative effect - that is, HRW did not work (Matsumoto et al, 2013; Yoritaka et al, 2018).
Sports Science
In sports science, the studies were very small, with 8-99 participants. The amount of HRW (both in volume and concentration) varied across all studies, and the methods varied widely. The studies mainly measured biomechanical markers during exercise to try and extrapolate whether there was a positive effect. In some studies there were changes to the biomechanical markers, however the studies were often too small to know if it was a true effect or if by chance. In some studies, the results showed no effect to performance (Valenta et al, 2022). In another study, participants who drank HRW water were less fatigued, however, the study was funded by a hydrogen water consortium, and the researchers found that the H2 was expired before they even commenced the exercise - so really it was just water vs water (Mikami et al, 2019).
The research is poor quality 🚩
The quality of these systematic reviews was questionable. That is, 1) they were in poor quality (and potentially predatory) journals and 2) the methods were poorly described and contradictory (which reinforces point 1). For example, in Dhillon et al (2024) the authors do not fully describe the methods they used to complete the systematic review, and diverted from their planned methods. Including that they completed no assessment of conflicts of interest or financial influence on the research they summarised. I’m also concerned that their search terms were inadequate, as they did not capture the same papers that Bai et al (2023) did when they assessed the impact on oral health. Similarly, Zhou et all provided little detail on their methods and did not synthesise their data in a meaningful way; they regurgitated a summary of each study with no particular critique (Zhou et al, 2024)
In Bai et al (2023) their conclusions did not match the results they described. This systematic review included all papers on HRW, including animal and mechanistic models - this is a major flaw. In addition, many of these articles did not even define what they meant by hydrogen water and the chemical properties they were referring to.
Why does any of that matter? Quality of data influences the results and how confidently we can say that something has a positive (or negative) effect. This is why clinical trials are so notoriously difficult. So imagine that not only are the clinical trials poorly done, but the study of these clinical trials is poorly done - you then have unreliable and garbage data. Garbage in, garbage out.
Ok, but what’s the overall verdict?
Hydrogen water does not treat a range of health conditions, as proposed by the companies that sell them. And while there is theory on why hydrogen water could possibly, maybe, be beneficial (aka hydrogen mops up free radicals), there is very little quality evidence that supports this.
Should I rush out and buy hydrogen water?
According to data from the Australian Bureau of Statistics (ABS), Australians consume approximately 1L of water on average per day, and less than 5% of the population eat the recommended amount of fruits and veggies per day. Which is where most of our antioxidant goodness comes from. So perhaps a better focus would be on increasing fruit and veg in our diet.
Do you need hydrogen water? No. But if it helps you increase your water intake, go for it.
Disclaimer:
This content is educational in nature and is not intended to be medical advice. For health advice that takes into account your own circumstances, see your health professional.
Peer review:
Thanks to my colleagues Dr Christian Moro and Dr Mike Todorovic who peer reviewed this article with specific attention to chemistry.
For the nerds:
I also searched different combinations of keywords “hydrogen water” as a keyword phrase (as opposed to hydrogen water as individual words) and with no filter there was 174 results. With filters for clinical trials or randomised control trials, there was a total of 7 papers. With the filter of “humans” there was 33 results. So I am very comfortable to stick my neck out and say that there is very little research on the health effects of hydrogen water in humans. Yes, it’s not a systematic review. Yes, it’s a single database - but there’s enough detail here for you to replicate, which is more than we can say about most of the research on this topic ;)
References:
Amarasooriya et al (2019) Removal of fluoride, hardness and alkalinity from groundwater by electrolysis. Groundwater for Sustainable development https://www.sciencedirect.com/science/article/abs/pii/S2352801X18302157
https://www.amnh.org/explore/ology/water/what-is-water
https://pubchem.ncbi.nlm.nih.gov/compound/Water#section=Density
https://www.britannica.com/science/hydrogen-bonding
https://www.sciencedirect.com/science/article/pii/S2352484722020625
Bai et al 2022. Effects of hydrogen rich water and pure water on periodontal inflammatory factor level, oxidative stress level and oral flora: a systematic review and meta-analysis. Annals of translational medicine. https://atm.amegroups.org/article/view/103538/html
Dhillon et al 2024. Hydrogen Water: Extra Healthy or a Hoax?—A Systematic Review. International journal of molecular sciences https://pmc.ncbi.nlm.nih.gov/articles/PMC10816294/
Matsumoto et al, 2013. Effect of supplementation with hydrogen-rich water in patients with interstitial cystitis/painful bladder syndrome. Urology. https://pubmed.ncbi.nlm.nih.gov/23374763/
Mikami et al, 2019. Drinking hydrogen water enhances endurance and relieves psychometric fatigue: a randomized, double-blind, placebo-controlled study. https://cdnsciencepub.com/doi/10.1139/cjpp-2019-0059
Smolinka et al 2022. The history of water electrolysis from its beginnings to the present. Electrochemical power sources: fundamentals, systems, and applications. https://www.sciencedirect.com/science/article/abs/pii/B9780128194249000100
Sim et al 2020. Hydrogen-rich water reduces inflammatory responses and prevents apoptosis of peripheral blood cells in healthy adults: a randomized, double-blind, controlled trial. Nature. https://www.nature.com/articles/s41598-020-68930-2
Yoritaka et al, 2018. Randomized, double-blind, multicenter trial of hydrogen water for Parkinson's disease. Movement Disorders. https://pubmed.ncbi.nlm.nih.gov/30207619/
Valenta et al, 2022. Acute pre-exercise hydrogen rich water intake does not improve running performance at maximal aerobic speed in trained track and field runners: A randomized, double-blind, placebo-controlled crossover study.PLoS One. https://pubmed.ncbi.nlm.nih.gov/36538554/
Zhoe et al, 2024. Hydrogen-Rich Water to Enhance Exercise Performance: A Review of Effects and Mechanisms. Metabolites. https://www.mdpi.com/2218-1989/14/10/537
