The question of whether or not hydrogen water has side effects is one of the most commonly asked questions we get, as well as the question with one of the most important answers to know. Unfortunately, we’re not yet clear on what are the side effects of hydrogen water. Researching this question was a part of a book chapter I recently wrote (soon to be published) for a major publisher. For this project, I documented all reported potential side effects of hydrogen water, as well as it’s safety profile. For this article, I will provide some anecdotal reports that have not been published in scientific literature in an attempt to properly investigate the answer to this critical question.
Reported Hydrogen Water Side Effects`
When I finished writing the book chapter in March 2019, there were 79 human publications that utilized molecular hydrogen therapy, in which a total of 1676 participants were involved. Since then, several other clinical trials have been published with no other reported adverse events. In total, nine potential adverse events have been recorded in a total of seven participants. The only adverse event that has been reported in more than a single participant is loose stool/diarrhea, with four participants reporting events at a frequency of 0.2% in the clinical research published. Another similar adverse event was reported citing increased frequency of bowel movement. It is important to note that four of these five events were reported in a single trial of only 20 participants, in which a magnesium rod was used. The literature reports virtually no magnesium entering the water, which may or may not be correct.
Increased exhaled hydrogen has been linked to irritable bowel syndrome.1 Lactose intolerance is actually the result of lactose passing to the small intestine, where it is consumed by bacteria, leading to excess hydrogen gas production.2 The extra gas then leads to discomfort, diarrhea, and bloating.2 Understanding the relationship between endogenous hydrogen gas production in individuals and the therapeutic effects of exogenous hydrogen gas consumption may be an important factor in determining responders and nonresponders, which means that some people will benefit from an intervention where others will not. This is true for virtually every intervention that has been demonstrated to work. This is a potential paradox, as hydrogen therapy has demonstrated beneficial results in various models of inflammatory bowel disease3, 4 and ulcerative colitis,5 and increasing endogenous production of molecular hydrogen via drugs such as acarbose has also shown to be effective in preclinical models of ulcerative colitis.6
In a single reported case in a diabetic patient, hydrogen water consumption led to hypoglycemia, which is low blood sugar. This was resolved in the patient by lowering their insulin levels, which is an objective benefit and not a side effect. This is not surprising, as hydrogen therapy has been shown in early clinical research to lower insulin in overweight participants.7 Drink HRW hydrogen tablets have been shown to improve insulin sensitivity in participants with nonalcoholic fatty liver disease. Further, hydrogen water has been shown to improve metabolic syndrome, a prediabetic state, in several clinical trials including a 60-participant, 24-week, double-blind, placebo-controlled trial using our hydrogen tablets, which saw a significant improvement in 18 of 20 measured outcomes.
Another single report cited potential heartburn in the same trial that saw four of the five gastrointestinal-related issues. This one is very unlikely to be related to hydrogen gas, as hydrogen water has been shown to improve the outcomes of gastroesophageal reflux disease (GERD) in a placebo-controlled trial involving 84 participants for 3 months,8 with heartburn being a significant symptom of GERD. Moreover, no adverse events were reported and there were significant improvements. Additionally, if the magnesium data in the open-label metabolic syndrome study was incorrect, it further decreases the likelihood that the hydrogen water intervention led to the heartburn, as magnesium is a treatment for heartburn.
A single other report of side effects involved cardiac failure in a patient undergoing hydrogen therapy. However, it should be noted that this trial involved the use of hydrogen therapy, via intravenous hydrogen saline, in hospitalized patients who were recovering from acute ischemic stroke.9 Cardiac arrest can happen immediately following ischemic stroke due to death of cardiac and neural myocytes in the post-ischemic stroke brain.10 In fact, according to the data collected from 9019 patients following acute ischemic stroke, 352 of them experienced cardiac arrest, a rate of 3.9%. In a trial utilizing intravenous hydrogen saline therapy with 38 patients enrolled, statistically, one or two of the participants (1482 participants is 3.9% of 38) were expected to experience cardiac arrest. Therefore, from these results, it cannot be concluded that hydrogen therapy caused cardiac failure.
Another single report published as part of the open-label metabolic syndrome study that recorded most of the adverse events noted a single incident of headache. Notably, of the nine reported adverse events across the 79 trials and 1676 participants (now 86 trials and closing in on 2000 participants), six of them were from a single study with 20 participants. This report of a headache is actually not that surprising to me. What surprises me is that there aren’t more reported headaches.
We keep a list of reported potential adverse events, and, while there are very few of them, headaches are the most prominently reported side effects. We have heard several times (roughly 10 times out of hundreds of thousands of bottles sold) of intense headaches following hydrogen water consumption. In every case, it was a new customer, and the headache was reported to occur after the first use of hydrogen water. Moreover, in every reported case, subsequent use has seen this issue go away (after two or three times consuming high-dose hydrogen water). We have also heard this anecdotally from a few other companies that deliver relatively high concentrations of hydrogen water. It is something to consider and is not impossible considering the evidence hydrogen therapy has the capacity to affect many neurological functions in various neurological disease models or raising alertness following sleep deprivation.
If a molecule plays a physiological role, there is the potential it can cause both beneficial and deleterious effects. To date, hydrogen therapy has been shown to demonstrate overwhelmingly positive results, with little to no negative consequences. However, that does not mean this is always the case in all participants.
The final reported adverse event was regarding patients with stage III and stage IV cancer, where the publication cited “minor events” that “spontaneously resolved,” without specifying the exact nature of the events and in how many participants they occurred.11 Despite the ambiguity, this is the area of reported adverse events I am most interested in. One hypothesis article speculates about several concerns regarding hydrogen therapy involving hydrogen-induced ghrelin-mediated risks and benefits. For example, hydrogen may increase ghrelin excretion, which may increase cancer risk.12 However, no such adverse events due to this hypothesized connection have been reported in either humans or animal models, and current evidence points to H2 being a potentially beneficial adjuvant therapy for various cancer models. This current evidence may get complicated, as in one case study where hydrogen therapy demonstrated a pseudo-progression followed by remission,13 similar to PD-1 treatment.14 We’ve seen a biphasic response with molecular hydrogen in an exercise model, where oxidative stress was acutely raised during exercise, followed by an aggressive decrease driving towards harmonious redox.15 This may have also been at play during a short trial using hydrogen inhalation for Parkinson’s Disease, in which oxidative stress was increased.16 Noted hydrogen therapy expert Tyler W. LeBaron has written extensively on this subject and has proposed that H2 works like a redox adaptogen and promotes beneficial hormesis.17
Furthermore, in discussing protocols for our collaborative group project that is underway, he suspects that hydrogen therapy could either be beneficial or deleterious to some cancer models, since H2 has beneficial effects on metabolism. After discussing with him some data recorded but not yet published in Asia, I got the impression that high-dose hydrogen therapy may see an improvement in decreasing cancer progression, whereas low-dose hydrogen therapy may actually speed up progression.
One thing is for certain: We need to do more research, as well as to thoroughly mine the consumer market for much-needed information. This is an important reason that I have started the not-for-profit myjourney.science, which I hope to be live and collecting data by early 2021.
Safety of Molecular Hydrogen
In the absence of data on adverse events, the question becomes, “What do we know about the safety of molecular hydrogen and the side effects of hydrogen water?” The answer is, in short, “Enough.” Molecular hydrogen is commonly used in deep-sea diving because it is far less narcotic than nitrogen gas or even helium gas. Data from mixed sea diving has revealed that hydrogen is very well tolerated by the body, while hydrogen narcosis occurs only at high pressure levels.18 Fortuitously, even when hydrogen narcosis is present, it has been observed that hydrogen-containing mixes may suppress high-pressure neurological symptoms.19 Importantly, the dosage of hydrogen needed under pressure to exhibit signs of narcosis is significantly higher than the dosage any commercial method (for example, via inhalation or dissolved in water) could deliver to consumers under even the most extreme circumstances. Thus, hydrogen narcosis (which exhibits no known long-term damages, toxicity, or side effects) is of relatively small concern.
Finally, humans produce up to 12 liters of molecular hydrogen gas per day through bacterial breakdown of carbohydrates in our digestive tracts,20 so the relatively small volumes of exogenous supplementation should, and have thus far demonstrated to, have a very high safety profile.
Contraindications of Hydrogen Water
There are currently no known contraindications of molecular hydrogen concerning either prescribed medications, supplements, or specific disease models. Larger trials are needed to determine whether molecular hydrogen will have any contraindications in specific populations or when administered with any prescribed medications. No contraindications have been identified so far.
Conclusion on the Side Effects of Hydrogen Water
At this time, molecular hydrogen appears to have an incredibly high safety profile, although new information could change this perspective. New and larger trials are needed to confirm or clarify the existing information. Additionally, additives in the hydrogen water source need to be considered. These include products that may contain aluminum, which is a known neurotoxin that accumulates in the brain as we age, 21or even magnesium. Magnesium is a critical mineral — a cofactor in over 300 enzymatic reactions within the body — and the majority of the population is deficient in it. That said, magnesium must be consumed in moderation and does come with a small risk of side effects and contraindications.22