Xylitol
In children, xylitol gum lowered cavities in a 2024 review, mainly where cavity rates were high, while candy studies mostly found no effect. A 33-month adult lozenge trial found no significant change. Fluoride toothpaste with xylitol cut cavities 13% in low-quality trials. Large doses caused watery stools, and higher blood xylitol tracked more heart events.
Add to Bio HackChecked 2026-11-12
- Status
- Sugar alcohol sold in the US as a sweetener and in gum, mints, lozenges and toothpaste. Not approved by the FDA as a drug for any use.
- Also called
- xylitol gum, xylitol mints, xylitol lozenges, xylitol syrup, xylitol candy, xylitol gummy bears, birch sugar, sugar alcohol, polyol, E967
- Taken for
- cavities, tooth decay, teeth, preventing cavities in children, cavity bacteria, passing cavity bacteria to babies
Strong several reviews agree · Moderate one review or consistent trials · Limited one or a few small studies · Untested no study in people, listed with what it rests on
Shown to help2
Reported risks2
- ModerateShown to raise gas, bloating and watery stools at single doses of 35 to 50 g. Cavity trials found similar side effect rates between groups.
- LimitedLinked to more heart events in people with the highest blood xylitol levels. Lab studies found xylitol raised clotting. A 5-week trial found no arterial change.
What people take it for, and what was found
Shown to help2
Cavities: xylitol in fluoride toothpaste (topical)
Limited evidence: children using fluoride toothpaste with xylitol had 13% fewer new cavities than with fluoride alone, in two studies by the same authors.
The numbers and sources
- Effect
- Over 2.5 to 3 years, children using fluoride toothpaste with 10% xylitol had 13% fewer new cavities than those using fluoride-only toothpaste (prevented fraction -0.13, 95% CI -0.18 to -0.08) [5].
- Population
- 4,216 children [5].
- Sources
- [5]
- Caveats
- Low-quality evidence. Both studies were run by the same authors in the same population [5].
Passing cavity bacteria from mother to child
Shown to lower cavity bacteria in children by about half when mothers chewed xylitol gum. Cavities themselves were not measured.
The numbers and sources
- Effect
- When mothers chewed xylitol gum, their children were less likely to carry mutans streptococci, the main cavity-linked bacteria, at 12 to 18 months (RR 0.54, 95% CI 0.39 to 0.73) and at 36 months (RR 0.56, 95% CI 0.40 to 0.79) [9].
- Population
- 601 mothers in 11 RCTs from 5 research teams [9].
- Sources
- [9]
- Caveats
- This measures bacteria, not cavities. The authors describe the long-term effect on the children's cavities as controversial [9].
Mixed results2
Cavities in children: gum and candies
Mixed results: xylitol gum lowered cavities in children where cavities were common, candies mostly did not, and reviews differ about tenfold in effect size.
The numbers and sources
- Effect
- In 10 chewing gum studies, xylitol gum lowered new cavities against no treatment or a placebo polyol gum, and the effect was clinically meaningful where cavity levels were high or moderate at baseline. In 5 of 6 candy studies, no effect was found [1]. A review of xylitol candies and lozenges found lower cavity increments in 2 of 3 studies, with no apparent effect on surfaces between teeth [2]. Pooled across products, one meta-analysis found fewer decayed, missing and filled teeth with xylitol than with all controls (SMD -1.09, 95% CI -1.34 to -0.83) [3]. Another found a much smaller effect (fixed-effect SMD -0.099, 95% CI -0.149 to -0.049), and its random-effects interval included no difference [4]. The Cochrane review found the evidence on lozenges, sucking tablets and wipes in children insufficient, with intervals compatible with both fewer and more cavities [5].
- Population
- Children and adolescents up to 18 in 15 trials of fair or low quality [1]. Children in 3 trials of at least 1 year [2]. Children and mother-child pairs in 16 studies [3]. 10 studies with 5,903 participants [5].
- Sources
- [1], [2], [3], [4], [5]
- Caveats
- The reviews differ roughly tenfold in effect size [3][4]. Daily dose and baseline cavity level confounded the results [1]. Most Cochrane trials were at high risk of bias [5].
Cavities in babies and young children: syrup and gummy bears
Limited evidence: xylitol syrup lowered decay in babies in one trial, while gummy bears did not change cavities in kindergarten children in another.
The numbers and sources
- Effect
- In 100 children aged 9 to 15 months, xylitol syrup at 8 g a day split into 2 doses lowered decayed teeth against a control syrup with 2.67 g xylitol (RR 0.30, 95% CI 0.13 to 0.66), and 8 g in 3 doses lowered them by half (RR 0.50, 95% CI 0.26 to 0.96). 24.2% and 40.6% of children in the xylitol groups had decay, against 51.7% on control [6]. In 562 kindergarten children given xylitol gummy bears at 7.8 g a day or placebo gummies for 9 months, new decayed, missing and filled surfaces did not differ in baby teeth (mean 5.0 against 4.0) or permanent teeth (0.38 against 0.48) by second grade [7].
- Population
- Children in the Marshall Islands, followed a mean 10.5 months [6]. Inner-city school children in East Cleveland, Ohio, randomized by classroom [7].
- Sources
- [6], [7]
- Caveats
- The Cochrane review rated the syrup trial low quality [5]. In the gummy bear trial both groups also received fluoride toothpaste, fluoride varnish and sealants, which the authors say may have masked an effect [7].
Not shown to help1
Cavities in adults: lozenges
One trial found xylitol lozenges lowered cavities 10% in adults at higher risk, not a significant difference.
The numbers and sources
- Effect
- In 691 adults at elevated risk of cavities, five 1 g xylitol lozenges a day for 33 months lowered the cavity increment by 10% against placebo lozenges. This was less than one third of a surface per year and was not statistically significant. There was no sign of a dose response [8].
- Population
- Adults aged 21 to 80 at three sites [8].
- Sources
- [8]
- Caveats
- One trial in adults with adequate fluoride exposure [8].
Doses studied
The syrup trial gave 8 g a day [6], the gummy bear trial 7.8 g a day in 3 servings [7] and the adult trial 5 g a day as five 1 g lozenges [8]. The toothpaste trials used fluoride toothpaste with 10% xylitol [5]. One review describes the products with effects in trials as 100% xylitol taken 3 to 5 times a day for 5 to 10 g a day [4].
Risks
Reported risks2
Gas, bloating and watery stools
Shown to raise gas, bloating and watery stools at single doses of 35 to 50 g. Cavity trials found similar side effect rates between groups.
The numbers and sources
- Effect
- Against 45 g sucrose, a single 50 g dose of xylitol in water raised the number of people reporting nausea, bloating, rumbling, colic and watery stools, and raised bowel movement frequency. 35 g raised watery bowel movements. At every dose tested, xylitol caused more watery stools than erythritol [10]. In 42 adults with obesity taking 24 g xylitol, 36 g erythritol or nothing daily for 5 weeks, a few diarrhea-related symptoms were reported [11]. Cavity trials listed mouth sores, cramps, bloating, constipation, flatulence and loose stools or diarrhea, and the trials that reported usable data found similar rates between groups [5].
- Population
- 70 young adults, 64 completing [10]. 42 adults with obesity [11]. Cavity trials in children and adults [5].
- Sources
- [10], [11], [5]
- Caveats
- The tolerance trial reported p values, not the size of the changes [10]. Many cavity trials did not report adverse effects [5].
Heart events and blood clotting
Linked to more heart events in people with the highest blood xylitol levels. Lab studies found xylitol raised clotting. A 5-week trial found no arterial change.
The numbers and sources
- Effect
- In 2,149 people having elective heart evaluations, those in the top third of fasting plasma xylitol had more major cardiovascular events over 3 years than those in the bottom third (adjusted HR 1.57, 95% CI 1.12 to 2.21). In isolated human platelets and in animals, xylitol raised platelet reactivity and clot formation. In 10 healthy volunteers, a xylitol-sweetened drink raised plasma xylitol and platelet responsiveness in every subject [12]. In 42 adults with obesity, 24 g a day for 5 weeks did not change arterial stiffness against no substance [11].
- Population
- A discovery cohort of 1,157 and a validation cohort of 2,149, plus 10 volunteers [12]. 42 adults with obesity [11].
- Sources
- [12], [11]
- Caveats
- The cohort finding is an association with blood levels, which also reflect xylitol the body makes, and does not show xylitol caused the events. The volunteer study measured platelet function, not clinical events, and the abstract describes no control group [12]. The 5-week trial was a small pilot [11].
Claims tested and not found
- That xylitol lozenges prevent cavities in adults. Cavities did not differ significantly from placebo over 33 months [8].
- That xylitol gummy bears add to other prevention in school children. New decayed, missing and filled surfaces did not differ from placebo [7].
- That xylitol candies prevent cavities in children. Five of six candy studies found no effect [1].
Sources
- Pienihäkkinen K, Hietala-Lenkkeri A, Arpalahti I, Söderling E. The effect of xylitol chewing gums and candies on caries occurrence in children: a systematic review with special reference to caries level at study baseline. European Archives of Paediatric Dentistry. 2024. https://doi.org/10.1007/s40368-024-00875-w
- Antonio AG, Pierro VS, Maia LC. Caries preventive effects of xylitol-based candies and lozenges: a systematic review. Journal of Public Health Dentistry. 2011. https://doi.org/10.1111/j.1752-7325.2010.00208.x
- Janakiram C, Deepan Kumar CV, Joseph J. Xylitol in preventing dental caries: A systematic review and meta-analyses. Journal of Natural Science, Biology and Medicine. 2017. https://doi.org/10.4103/0976-9668.198344
- ALHumaid J, Bamashmous M. Meta-analysis on the Effectiveness of Xylitol in Caries Prevention. Journal of International Society of Preventive and Community Dentistry. 2022. https://doi.org/10.4103/jispcd.jispcd_164_21
- Riley P, Moore D, Ahmed F, et al. Xylitol-containing products for preventing dental caries in children and adults. Cochrane Database of Systematic Reviews. 2015. https://doi.org/10.1002/14651858.CD010743.pub2
- Milgrom P, Ly KA, Tut OK, et al. Xylitol pediatric topical oral syrup to prevent dental caries: a double-blind randomized clinical trial of efficacy. Archives of Pediatrics & Adolescent Medicine. 2009. https://doi.org/10.1001/archpediatrics.2009.77
- Lee W, Spiekerman C, Heima M, et al. The effectiveness of xylitol in a school-based cluster-randomized clinical trial. Caries Research. 2015. https://doi.org/10.1159/000360869
- Bader JD, Vollmer WM, Shugars DA, et al. Results from the Xylitol for Adult Caries Trial (X-ACT). Journal of the American Dental Association. 2013. https://doi.org/10.14219/jada.archive.2013.0010
- Lin HK, Fang CE, Huang MS, et al. Effect of maternal use of chewing gums containing xylitol on transmission of mutans streptococci in children: a meta-analysis of randomized controlled trials. International Journal of Paediatric Dentistry. 2016. https://doi.org/10.1111/ipd.12155
- Storey D, Lee A, Bornet F, Brouns F. Gastrointestinal tolerance of erythritol and xylitol ingested in a liquid. European Journal of Clinical Nutrition. 2007. https://doi.org/10.1038/sj.ejcn.1602532
- Bordier V, Teysseire F, Drewe J, et al. Effects of a 5-week intake of erythritol and xylitol on vascular function, abdominal fat and glucose tolerance in humans with obesity: a pilot trial. BMJ Nutrition, Prevention & Health. 2023. https://doi.org/10.1136/bmjnph-2023-000764
- Witkowski M, Nemet I, Li XS, et al. Xylitol is prothrombotic and associated with cardiovascular risk. European Heart Journal. 2024. https://doi.org/10.1093/eurheartj/ehae244