InflammationHealthy ageingRandomised, double-blind
Healthy adults showed lower inflammatory activity after four weeks
Compared with plain water, the hydrogen water group showed higher antioxidant capacity, fewer pro-inflammatory immune cells and less cell death in blood samples. Genes linked to inflammatory responses were dialled down.
Worth knowing and source
The boost in antioxidant capacity was seen in participants over 30, but not in those under 30.
Sim M, et al. (2020). Scientific Reports, 10, 12130.
Read the study ↗
InflammationOpen-label pilot
Lower oxidative stress and joint scores in an inflammatory joint condition
People with rheumatoid arthritis drank high-concentration hydrogen water daily. A marker of oxidative damage to DNA fell by 14% on average, and disease activity scores improved over the study.
Worth knowing and source
There was no placebo group, so some improvement could be due to other factors. Participants continued their usual treatment. Included here for information only.
Ishibashi T, et al. (2012). Medical Gas Research, 2, 27.
Read the study ↗
InflammationMetabolic healthRandomised, double-blind
Six months of hydrogen water improved cholesterol, glucose and inflammation markers
Adults with metabolic syndrome drank high-concentration hydrogen water or a placebo. The hydrogen group saw significant drops in blood cholesterol, glucose and HbA1c, with better markers of inflammation and antioxidant balance. Waist-to-hip ratio and BMI also trended slightly down.
Worth knowing and source
The hydrogen water was made with tablets at a higher concentration than most bottles produce. Participants had metabolic syndrome, so results may differ in healthy people.
LeBaron TW, et al. (2020). Diabetes, Metabolic Syndrome and Obesity, 13, 889 to 896.
Read the study ↗
Brain and moodPlacebo-controlled
Better mood, less anxiety and improved nervous system balance in daily life
Adult volunteers drank hydrogen water or placebo water every day. The hydrogen group reported improvements in mood and anxiety, and tests showed better autonomic nerve function, the system that balances stress and relaxation.
Worth knowing and source
A small study using questionnaires and physiological tests. The authors suggest hydrogen water may support quality of life, but larger trials are needed.
Mizuno K, et al. (2018). Medical Gas Research, 7(4), 247 to 255.
Read the study ↗
Brain and moodRandomised, double-blind
A year-long trial on memory, with promising results in one genetic group
People with mild memory decline drank hydrogen water or placebo for a year. Across the whole group there was no significant difference, but carriers of the APOE4 gene in the hydrogen group improved on overall memory scores and word recall. In a linked mouse study, hydrogen water reduced oxidative stress and memory decline.
Worth knowing and source
The main result for the whole group was not significant. The positive finding was in a subgroup, which needs confirming in a larger trial.
Nishimaki K, et al. (2018). Current Alzheimer Research, 15(5), 482 to 492.
Read the study ↗
Brain and moodEnergy and fatiguePilot trial
One drink of hydrogen water improved alertness after a sleepless night
Sleep-deprived young adults who habitually drink coffee were given hydrogen water or caffeine. A single dose of hydrogen water improved alertness, and the researchers compared its effects on brain metabolism with caffeine's.
Worth knowing and source
A pilot trial measuring a limited number of brain outcomes. The authors call for further research comparing hydrogen water and caffeine.
Hydrogen-rich water and caffeine for alertness and brain metabolism in sleep-deprived habitual coffee drinkers (2021). Food Science & Nutrition, 9(9), 5139 to 5145.
Read the study ↗
Energy and fatigueExercise and recoveryRandomised, double-blind
Less fatigue and better endurance when drunk just before exercise
In 99 untrained adults, those who drank hydrogen water 30 minutes before mild exercise reported significantly less fatigue. In 60 trained adults who drank it 10 minutes before exercise, endurance improved, measured by maximal oxygen uptake, and exercise felt easier.
Worth knowing and source
Effects were measured right after a single drink, so this shows short-term effects rather than long-term changes.
Mikami T, et al. (2019). Canadian Journal of Physiology and Pharmacology, 97, 857 to 862.
Read the study ↗
Exercise and recoveryEnergy and fatigueDouble-blind crossover
Lower lactate and less muscle fatigue in elite footballers
Young male footballers drank hydrogen water or placebo for a week before hard exercise. With placebo, blood lactate rose and muscle strength dropped during repeated leg extensions. With hydrogen water, lactate stayed lower and early strength loss was prevented.
Worth knowing and source
A small pilot study in young male athletes. Results may differ in other groups.
Aoki K, et al. (2012). Medical Gas Research, 2, 12.
Read the study ↗
Exercise and recoveryPlacebo-controlled
Less muscle soreness after a weights session
Drinking hydrogen water at intervals around resistance training improved muscle performance, lowered blood lactate during and straight after the session, and reduced delayed-onset muscle soreness compared with placebo.
Worth knowing and source
This looked at a single training session, so it shows short-term effects.
Hydrogen rich water consumption positively affects muscle performance, lactate response, and alleviates delayed onset of muscle soreness after resistance training (2022). Journal of Strength and Conditioning Research, 36(10), 2792 to 2799.
Read the study ↗
Exercise and recoveryPlacebo-controlled
Better recovery after two hard sessions in one day
Elite fin swimmers completed two strenuous training sessions on the same day, drinking hydrogen water or placebo. Hydrogen water lowered a blood marker of muscle damage (creatine kinase) and supported recovery of muscle performance and soreness over 24 hours.
Worth knowing and source
A small group of elite athletes. Results may not apply to everyone.
Hydrogen-rich water supplementation promotes muscle recovery after two strenuous training sessions performed on the same day in elite fin swimmers (2024). Frontiers in Physiology.
Read the study ↗
Exercise and recoveryRandomised, double-blind crossover
Eight days of hydrogen water improved muscular endurance
Trained men drank hydrogen water or placebo for eight days around resistance training. Muscular endurance improved significantly with hydrogen water, which the authors describe as a promising strategy for people looking to boost endurance in training.
Worth knowing and source
In this study, hydrogen water alone did not speed up recovery from muscle soreness after high-intensity training.
Zhou K, et al. (2024). Frontiers in Physiology, 15.
Read the study ↗
Healthy ageingRandomised, controlled pilot
Six months of hydrogen water and markers of ageing in the over-70s
Older adults drank hydrogen water or a control drink daily. Researchers measured blood markers, brain metabolism, physical function, skin, sleep and quality of life. Telomeres, the protective caps on chromosomes that shorten with age, lengthened in the hydrogen group but shortened in the control group.
Worth knowing and source
A pilot trial. The hydrogen water was made with tablets at a much higher concentration than a bottle produces, and the research was supported in part by a hydrogen tablet company.
Zanini D, et al. (2021). Experimental Gerontology, 155, 111574.
Read the study ↗
Gut healthRandomised, double-blind
More beneficial gut bacteria in just two weeks
Healthy men drank hydrogen-containing water or purified tap water daily. Bifidobacterium, a beneficial gut bacterium, increased in 9 out of 10 people in the hydrogen group, and their digestion moved towards the "normal" range on the Bristol stool scale.
Worth knowing and source
The water was alkaline electrolysed water with a low hydrogen level (0.3 ppm), and the study was funded by Panasonic. Overall gut diversity did not change.
Tanaka Y, et al. (2021). Medical Gas Research, 11(4), 138 to 144.
Read the study ↗
Gut healthControlled study
Higher antioxidant activity and changes in gut flora in young athletes
Female youth footballers in intensive training drank hydrogen water over several weeks. A marker of oxidative damage (malondialdehyde) fell, total antioxidant capacity rose, and the make-up of their gut bacteria changed.
Worth knowing and source
A small group of young athletes in heavy training, so results may differ in other people.
Sha JB, et al. (2018). Medical Gas Research, 8, 135 to 143.
Read the study ↗
Gut healthMetabolic healthRandomised, double-blind
Blood sugar and gut bacteria in people with raised fasting glucose
Adults with raised fasting blood sugar drank hydrogen water or pure water for eight weeks. Both groups' fasting glucose fell, but with a significant difference in favour of hydrogen water, which also improved signs of gut bacteria imbalance.
Worth knowing and source
The authors describe the improvements as slight, and call for more research.
Liang B, et al. (2023). Antioxidants, 12(6), 1245.
Read the study ↗
SkinBathing study
Fewer wrinkles and blotches with daily hydrogen water baths
Daily 10-minute baths in warm hydrogen-rich water, plus hydrogen water face towels, roughly halved wrinkle scores over the study period. Skin moisture also improved in people whose skin started out dry.
Worth knowing and source
This study used hydrogen water on the skin, not drinking it. It was small, without a control group. Research on drinking hydrogen water for skin is still limited.
Tanaka Y, Miwa N. (2022). Hydrogen, 3(2), 161 to 178.
Read the study ↗
Energy and fatigueExercise and recoveryMeta-analysis of trials
Pooling the trials: hydrogen reduced fatigue in healthy adults
This systematic review combined randomised controlled and crossover trials in healthy adults. It found moderate evidence that hydrogen supplementation reduces fatigue during exercise, measured by how hard exercise feels.
Worth knowing and source
The same analysis found hydrogen did not improve aerobic capacity (VO2max). It included studies of inhaled hydrogen gas as well as hydrogen water.
Zhou K, et al. (2023). Frontiers in Nutrition.
Read the study ↗
Exercise and recoveryDouble-blind crossover
A week of hydrogen water boosted sprint power in trained cyclists
After seven days of hydrogen water, trained cyclists raised their peak power in a maximal sprint test from 766 to 827 watts on average, increased their mean power and showed a lower fatigue index, compared with placebo.
Worth knowing and source
Only the trained cyclists improved. The untrained group did not, and aerobic (VO2max) performance didn't change. The water used was 1.9 ppm, below the DOUSE H8's 3 ppm maximum.
Timón R, et al. (2021). Biology of Sport, 38(2), 269 to 275.
Read the study ↗
Exercise and recoveryRandomised, single-blind pilot
More power and faster heart rate recovery in elite rowers
Elite dragon boat athletes training four hours a day drank hydrogen water or placebo water for a week. The hydrogen group increased maximum and average power in a 30-second rowing test, with a lower peak heart rate and better heart rate recovery after exercise.
Worth knowing and source
A small pilot study with nine people in each group.
Dong G, et al. (2022). International Journal of Environmental Research and Public Health, 19(9), 5413.
Read the study ↗
Exercise and recoveryRandomised, double-blind crossover
Runners lasted longer before exhaustion
Amateur middle-distance runners drank 500 ml of hydrogen water or placebo 30 minutes before testing. With hydrogen water, they ran longer before exhaustion, rated the effort as easier and had a lower peak heart rate.
Worth knowing and source
There was no effect on maximal aerobic speed or jumping performance.
Jebabli N, et al. (2023). Frontiers in Physiology, 14, 1240871.
Read the study ↗
The foundationsAnimal and lab
The 2007 paper that started it all
Published in Nature Medicine, this study showed in cells and animals that molecular hydrogen selectively neutralised the most damaging oxygen radicals, while leaving the useful signalling molecules the body needs alone. It sparked most of the research that followed.
Worth knowing and source
This was not a study of people drinking hydrogen water. It explains the "selective antioxidant" idea that later human trials tested.
Ohsawa I, et al. (2007). Nature Medicine, 13, 688 to 694.
Read the study ↗
