Water Kefir (Tibicos)
Water kefir, also called tibicos, is a dairy-free drink made by fermenting sugar water, often with dried fruit or fruit juice, with water kefir grains. The grains are gel-like clumps of dextran, a glucose polymer made by lactic acid bacteria, holding lactic acid bacteria, yeasts and acetic acid bacteria. It is a different culture from milk kefir and is grown on a different substrate, so milk kefir research does not carry over. The microbes vary widely by grain source, and the finished drink is sour, fizzy and slightly alcoholic: 13 commercial samples in Argentina held 0.58% to 2.55% alcohol by volume. It is sold as a drink, as grains and as starter cultures. Human research is very thin. One uncontrolled 14-day study in 40 healthy adults found shifts in the overall mix of gut bacteria, with no change in the variety of species within each sample, and some people reported more gas or bloating. Other proposed effects come from lab and animal studies.
Benefits
Gut bacteria composition
In 40 healthy adults who drank 200 mL of home-made water kefir a day for 14 days, the overall makeup of stool bacteria shifted, and groups such as Bifidobacterium, Blautia and Roseburia rose, while diversity within each sample did not change. There was no control group, and these are microbiome measures, not health outcomes.
Digestive symptoms when starting the drink
In the same 14-day study, 66% of people reported no change in digestive symptoms. Some reported more gas (32%) or bloating (24%), while 28% reported less abdominal pain. The questionnaire was not a validated clinical tool, and without a control group these reports cannot be credited to water kefir.
Gut microbial fermentation in a lab colon model (lab work)
In a lab model of the human colon, water kefir raised short-chain fatty acid production and Bifidobacterium and lowered protein fermentation compounds; pasteurized versions also helped a cell model of the gut lining. The study was run by a contract lab with a food company that took part in its design. It has not been repeated in people.
Gut lining and inflammation markers (animal work)
In mice given a chemical that inflames the colon, a water kefir microbial consortium lessened weight loss, colon shortening and tissue damage, and restored gut barrier proteins and inflammation markers compared with untreated mice. This was an animal model, and the dose cannot be translated to a drink for people.
Airway immune response (animal work)
In mice, 6 days of oral water kefir raised antiviral interferons in the airways after an immune challenge that mimics a virus, and in mice then infected with respiratory syncytial virus it lowered virus levels and reduced lung tissue damage compared with untreated mice. No study has tested immune effects of water kefir in people.
Mechanism of action
Dextran grains and fermentation products
The grains are built mainly from dextran, made by Lentilactobacillus hilgardii. In one lab fermentation, the added sucrose was fully broken down within 24 hours, the main products were ethanol and lactic acid, with smaller amounts of glycerol, acetic acid and mannitol, and the pH fell from 4.26 to 3.45 over 72 hours.
Live microbes that differ between grains
Grains from different places hold different microbes: Lactobacillus hordei and L. nagelii led in two grains analyzed in Germany, Leuconostoc in a third, and the ethanol-producing bacterium Zymomonas in four water kefirs from the UK, Canada and the US. In the human study, Lactobacillus and Leuconostoc led in the drink but were absent or low in stool, so lasting colonization was not shown.
Single strains isolated from the grains (lab and animal work)
Researchers have isolated single strains from water kefir grains and tested them on their own. A Lactobacillus paracasei strain from Malaysian grains improved insulin tolerance in mice with induced diabetes. A single isolated strain is not the same as the drink, and these results have not been tested in people.
Clinical trials
Exploratory single-arm before and after study with no control group; participants brewed water kefir at home from supplied grains, cane sugar, rosehip powder, citric acid and a dried apricot (48 hours of fermentation) and drank 200 mL a day for 14 days; primary outcome gut microbiota composition by 16S sequencing; no power calculation; registered NCT05657730; funded by internal Lund University department funds, with no competing interests declared (de Mel et al. 2026, Sci Rep)
48 healthy adults aged 18 to 65 in Lund, Sweden, enrolled; 40 provided both stool samples and were analyzed, and 38 completed the symptom questionnaire.
Alpha diversity did not change (Shannon p = 0.54), while overall community makeup shifted (p = 0.025), with a small effect size. Bacteroidetes and Actinobacteria rose and Firmicutes fell; Blautia, Roseburia faecis, Bifidobacterium and several Bacteroides species rose, and Akkermansia muciniphila fell. Gas (32%) and bloating (24%) increased in some people, while 28% reported less abdominal pain. Diet was not recorded, and the authors note that placebo effects and time cannot be excluded.
Laboratory study; pasteurized and unpasteurized water kefir products tested in a model that mimics colonic fermentation and in a cell model of the intestinal lining; carried out by a contract research lab with staff of a food company who helped design the study and interpret the data (Calatayud et al. 2021, Nutrients)
No human participants; human fecal microbial communities and gut cell cultures in the laboratory.
Water kefir raised short-chain fatty acid production and Bifidobacterium and lowered proteolytic fermentation compounds. These effects were stronger after pasteurization, and pasteurized products improved inflammation-induced barrier disruption in the cell model and raised IL-10 and IL-1 beta compared with control.
Animal study; a water kefir microbial consortium, mainly Acetobacter, Lactobacillus and Komagataeibacter bacteria with Saccharomyces and Talaromyces fungi, given to mice with dextran sodium sulfate induced colitis (Ye et al. 2023, Food Funct)
Mice; no human participants.
The consortium lessened weight loss, colon shortening and colon tissue damage, restored tight junction proteins (occludin, ZO-1 and claudin-1), shifted inflammatory and anti-inflammatory markers toward normal and changed the gut microbiota compared with untreated colitis mice. Results in an animal model do not show an effect in people.
Animal study; oral water kefir or kefiran given to mice for 6 days, followed by activation of the TLR3 pathway or infection with respiratory syncytial virus; no conflicts of interest declared (Dentice Maidana et al. 2024, Biomolecules)
Mice; no human participants.
After TLR3 activation, water kefir raised interferons (IFN-beta and IFN-gamma) and antiviral factors in the respiratory tract and shifted the balance of inflammatory and anti-inflammatory cytokines. In mice then infected with respiratory syncytial virus, it lowered virus replication and reduced lung tissue damage compared with untreated mice. No human study has tested this.
Animal study; a single Lactobacillus paracasei strain isolated from Malaysian water kefir grains, at a low and a high dose, given to mice with diabetes induced by a high-fat diet and streptozotocin, with glucose, insulin, liver antioxidants and liver gene expression measured after 14 weeks (Talib et al. 2024, Probiotics Antimicrob Proteins)
Mice; no human participants.
The insulin tolerance test area under the curve was about 2,425 and 2,018 mmol/L x min with the low and high doses, compared with about 3,885 in untreated diabetic mice, and genes related to glucose and lipid handling changed. This tested one isolated strain, not water kefir itself.
Microbiome sequencing and chemical screening of water kefir fermented in Malaysia, plus a subchronic toxicity study giving mice 2.5 or 10 mL per kg a day; no competing interests declared (Kumar et al. 2021, BMC Complement Med Ther)
BALB/c mice; no human participants.
The most abundant bacterium was Lactobacillus hilgardii, followed by Lactobacillus harbinensis and Acetobacter lovaniensis. Mice showed no signs of toxicity, behavior changes or adverse effects on survival, body weight, blood chemistry or tissue examination. Animal safety data do not establish safety in people.
Side effects and drug interactions
Common Potential side effects
Important Drug interactions
Frequently asked questions about Water Kefir (Tibicos)
What is water kefir, and how is it different from milk kefir?
Water kefir is sugar water or fruit juice fermented with water kefir grains, also called tibicos. The grains are made mainly of dextran and hold lactic acid bacteria, yeasts and acetic acid bacteria. Milk kefir uses different grains, made of kefiran and holding species such as Lactobacillus kefiranofaciens, and ferments milk, so the two drinks differ in microbes and composition. Water kefir contains no dairy.
How much research has been done on water kefir in people?
Very little. The only published human study found was a 14-day trial in 40 healthy adults with no control group, which looked at gut bacteria. A registered trial of 250 mL a day in young women has no published results yet. Most claims about water kefir come from lab and animal studies.
Does water kefir contain alcohol or sugar?
Yes, usually some of both. Thirteen commercial samples in Argentina held 0.58% to 2.55% alcohol, and alcohol rises with longer fermentation. It is brewed with sugar, and leftover sugar varies by recipe and fermentation time, so check the label or account for it when brewing at home.
Is a water kefir starter culture or powder the same as the drink?
Not necessarily. Grains from different sources hold different microbes, and defined starter cultures are not yet common. The only human study used home-brewed drinks from live grains; no human study has tested powders or capsules, so their effects are unknown.
Is homemade water kefir safe to make?
It can be, with care. Use clean glass jars and equipment, wash your hands, and refrigerate the drink after fermenting, as in the human study. Water kefir made or stored without proper hygiene can become contaminated with unwanted bacteria or molds, and longer fermentation raises the alcohol content.
What is Water Kefir?
Water kefir, also called tibicos, is a dairy-free drink made by fermenting sugar water, often with dried fruit or fruit juice, with water kefir grains. The grains are gel-like clumps of dextran, a glucose polymer made by lactic acid bacteria, holding lactic acid bacteria, yeasts and acetic acid bacteria.
What is Water Kefir used for?
NutraSmarts does not list Water Kefir under a health category. What the research covers: In 40 healthy adults who drank 200 mL of home-made water kefir a day for 14 days, the overall makeup of stool bacteria shifted, and groups such as Bifidobacterium, Blautia and Roseburia rose, while diversity within each sample did not chang…
What is the recommended dosage of Water Kefir?
The clinically studied dose is Human: 200 mL a day of home-made water kefir for 14 days, in one uncontrolled study. Animal safety testing used 2.5 and 10 mL per kg of body weight a day in mice. No human trials of powders, capsules or starter cultures were found. Always follow the product label and check with a healthcare provider for personal advice.
Does Water Kefir interact with any medications?
Possible interactions include: Medicines that should not be combined with alcohol: water kefir can contain alcohol, at 0.58% to 2.55% by volume in 13 commercial samples and higher in long home fermentations. Ask your pharmacist if your medicine carries an alcohol warning. If you take prescription medication, check with a pharmacist or doctor before using it.
How strong is the scientific evidence for Water Kefir?
NutraSmarts rates the evidence for Water Kefir as Preliminary (1 out of 5). It is backed by 6 study summaries and 14 cited references summarized on this page. A higher rating reflects more, larger, and better-designed human studies.
References(14 citations)
Evidence ratings on NutraSmarts are based on the totality of human clinical research, with emphasis on randomized controlled trials, meta-analyses, and systematic reviews. The references below directly support claims made throughout this page.
- An update on water kefir: Microbiology, composition and production. Int J Food Microbiol. 2021;345:109128. doi: 10.1016/j.ijfoodmicro.2021.109128.PubMedUsed to support: Review of water kefir: a sparkling, slightly acidic drink made by fermenting a sucrose solution with dried fruit and water kefir grains, gelatinous grains holding lactic acid bacteria, yeasts and acetic acid bacteria in a polysaccharide matrix that lactic acid bacteria produce. Which species dominate depends on the grains' geographic origin and the fermentation substrate and conditions, and defined starter cultures are not commonly used. Two authors are from a brewing company's innovation center.
- Challenges in water kefir production and limitations in human consumption: A comprehensive review of current knowledge. Heliyon. 2024;10(13):e33501. doi: 10.1016/j.heliyon.2024.e33501.PubMedUsed to support: Review of water kefir production, microbes and limitations. Water kefir is a dairy-free drink made by fermenting a sucrose solution with fruits and water kefir grains, which hold lactic acid bacteria, acetic acid bacteria and yeasts. The full text states that dextran made by Lentilactobacillus hilgardii is the main polysaccharide of the grains, while milk kefir grains can hold species not found in water kefir, such as the kefiran producer Lactobacillus kefiranofaciens; that alcohol is generally below 1%; that improperly prepared or stored water kefir can be contaminated with unwanted bacteria, molds or pathogens; and that Australian rules cap water kefir sold as a brewed soft drink at 1.15% alcohol by volume. Proposed health effects come mainly from lab and animal studies.
- Microbial species diversity, community dynamics, and metabolite kinetics of water kefir fermentation. Appl Environ Microbiol. 2014;80(8):2564-72. doi: 10.1128/AEM.03978-13.PubMedUsed to support: Lab study following one water kefir fermentation for 192 hours. Most microbes lived on the grains, which are made of polysaccharide; the main species were Lactobacillus casei/paracasei, L. harbinensis, L. hilgardii, Bifidobacterium psychraerophilum/crudilactis, Saccharomyces cerevisiae and Dekkera bruxellensis. Sucrose was fully converted within 24 hours; the main metabolites were ethanol and lactic acid, with low glycerol, acetic acid and mannitol, and the pH fell from 4.26 to 3.45 in the first 72 hours.
- The microbial diversity of water kefir. Int J Food Microbiol. 2011;151(3):284-8. doi: 10.1016/j.ijfoodmicro.2011.09.016.PubMedUsed to support: Culture-based study of three water kefirs of different origins made with water, dried figs, lemon and sucrose. Lactobacillus made up 82.1% and 72.1% of bacterial isolates in two of them, mainly L. hordei and L. nagelii, while Leuconostoc mesenteroides (28%) and Lc. citreum (24.3%) led in the third. Acetobacter species and the yeasts Saccharomyces cerevisiae, Lachancea fermentati, Hanseniaospora valbyensis and Zygotorulaspora florentina were also found, and several lactic acid bacteria produced polysaccharide from sucrose.
- Sequence-based analysis of the microbial composition of water kefir from multiple sources. FEMS Microbiol Lett. 2013;348(1):79-85. doi: 10.1111/1574-6968.12248.PubMedUsed to support: DNA sequencing of four water kefirs from the UK, Canada and the US. The bacterial fraction of each drink and grain was dominated by Zymomonas, an ethanol-producing bacterium, with lactic acid bacteria and acetic acid bacteria also present; yeasts included Dekkera, Hanseniaspora, Saccharomyces, Zygosaccharomyces, Torulaspora and Lachancea. The drink is described as lightly carbonated, acidic and low in alcohol.
- Water kefir grains vs. milk kefir grains: Physical, microbial and chemical comparison. J Appl Microbiol. 2022;132(6):4349-4358. doi: 10.1111/jam.15532.PubMedUsed to support: Lab comparison of water kefir and milk kefir grains. The two differed significantly in microbial content, chemical makeup, color and internal structure; milk kefir grains had more nutritional content, and the microbial variety of water kefir grains was wider and affected the resulting drinks.
- Changes in gut microbiota composition following water kefir consumption in healthy adults. Sci Rep. 2026;16(1):16006. doi: 10.1038/s41598-026-53645-7.PubMedUsed to support: Exploratory single-arm before and after study (registered NCT05657730) with no control group; 48 healthy adults in Sweden enrolled and 40 were analyzed. Participants brewed water kefir at home (grains, raw cane sugar, rosehip powder, citric acid and a dried apricot, fermented 48 hours) and drank 200 mL a day for 14 days. Alpha diversity did not change, while beta diversity differed before and after (p = 0.025, modest effect); Bacteroidetes and Actinobacteria rose, Firmicutes fell, and Blautia, Roseburia faecis, Bifidobacterium and several Bacteroides species rose. Some reported more flatulence (32%) or bloating (24%), 28% less abdominal pain and 66% no change. The full text describes the grain matrix as mainly dextran made by Lactobacillus hilgardii and notes that diet was not recorded and placebo effects and time cannot be excluded. Funded by internal university funds; no competing interests declared.
- Water Kefir and Derived Pasteurized Beverages Modulate Gut Microbiota, Intestinal Permeability and Cytokine Production In Vitro. Nutrients. 2021;13(11):3897. doi: 10.3390/nu13113897.PubMedUsed to support: Lab study, not a human trial, using models of colonic fermentation and the intestinal lining. Water kefir raised short-chain fatty acid production, lowered proteolytic fermentation compounds and raised Bifidobacterium; pasteurization enhanced these effects, and pasteurized products improved inflammation-induced barrier disruption and raised IL-10 and IL-1 beta versus control. Authors were employed by the contract lab and by a food company, whose scientists took part in design, analysis and the decision to publish.
- Prevention of DSS-induced colitis in mice with water kefir microbiota via anti-inflammatory and microbiota-balancing activity. Food Funct. 2023;14(15):6813-6827. doi: 10.1039/d3fo00354j.PubMedUsed to support: Mouse study. A water kefir microbial consortium, mainly Acetobacter, Lactobacillus and Komagataeibacter bacteria with Saccharomyces and Talaromyces fungi, lessened weight loss, colon shortening and tissue damage in mice with chemically induced colitis, restored tight junction proteins and inflammatory markers, and changed the gut microbiota. Animal evidence only.
- Modulation of the Gut-Lung Axis by Water Kefir and Kefiran and Their Impact on Toll-like Receptor 3-Mediated Respiratory Immunity. Biomolecules. 2024;14(11):1457. doi: 10.3390/biom14111457.PubMedUsed to support: Mouse study. Oral water kefir or kefiran for 6 days raised interferons and antiviral factors in the respiratory tract after TLR3 activation, shifted the balance of inflammatory and anti-inflammatory cytokines, reduced respiratory syncytial virus replication and lessened lung tissue damage. The authors note that water kefir and kefiran had not been studied before in respiratory viral infections. Animal evidence only; no conflicts of interest declared.
- Anti-Diabetic Effect of Lactobacillus Paracasei Isolated from Malaysian Water Kefir Grains. Probiotics Antimicrob Proteins. 2024;16(6):2161-2180. doi: 10.1007/s12602-023-10159-2.PubMedUsed to support: Mouse study of a single Lactobacillus paracasei strain isolated from Malaysian water kefir grains, given for 14 weeks to mice with diabetes induced by a high-fat diet and streptozotocin. The insulin tolerance test area under the curve was 2424.50 and 2017.50 mmol/L x min with the low and high doses versus 3884.50 in untreated diabetic mice, and liver genes related to glucose and lipid handling changed. Tests one isolated strain, not the drink; animal evidence only.
- Metagenomic and phytochemical analyses of kefir water and its subchronic toxicity study in BALB/c mice. BMC Complement Med Ther. 2021;21(1):183. doi: 10.1186/s12906-021-03358-3.PubMedUsed to support: Analysis of water kefir fermented in Malaysia and a subchronic toxicity study in mice. The most abundant bacterium was Lactobacillus hilgardii, followed by L. harbinensis, Acetobacter lovaniensis, L. satsumensis, A. tropicalis, L. zeae and Oenococcus oeni, and flavonoid and phenolic acid derivatives were the main bioactive compounds found. Mice given 2.5 or 10 mL per kg a day showed no signs of toxicity, behavior changes or adverse effects. Animal evidence only.
- [Analysis of sugary kefir samples for the development of a regulatory framework in the Argentinian Food Code]. Rev Argent Microbiol. 2025;57(3):298-303. doi: 10.1016/j.ram.2025.02.002.PubMedUsed to support: Article in Spanish with an English abstract. Analysis by Argentina's national food institute of 13 water kefir samples from Argentine producers: pH 2.9 to 3.7, alcohol 0.58% to 2.55% by volume, lactic acid bacteria about 1x10^7 CFU per mL, yeasts about 1x10^6 CFU per mL and enterobacteria below 10 CFU per mL. The data led to a 2024 article adding water kefir to the Argentine Food Code.
- [Ethanol content of Kefir water]. Blutalkohol. 1994;31(2):76-9..PubMedUsed to support: Article in German with an English abstract, from a Swiss forensic medicine institute, prompted by a legal case about blood alcohol. A home water kefir recipe (about 120 g of grains, 150 g of sugar, 2 figs and a lemon) reached up to 16 g of ethanol per liter on the second day of fermentation and up to 38 g per liter after 7 to 10 days. The authors note the relevance for judging fitness to drive.