Xylitol vs. erythritol: Understanding and misunderstandings

Xylitol and erythritol are both sugar alcohols, or polyols, that are used as sugar substitutes. While both are known for their ability to inhibit Streptococcus mutans, reduce bacterial adhesion to teeth, and stimulate saliva flow, studies suggest erythritol may offer even greater protection by reducing plaque accumulation and delaying the onset of cavities.

Three clinical studies lasting two to six months, and one lasting three years,¹ have demonstrated that consumption of candy or chewable tablets containing erythritol (5–7.5 gm per day) inhibited formation of dental plaque in young children, teenagers, and adults.^2-4 In vitro studies suggest that erythritol, and also sorbitol and xylitol, inhibit bacterial growth due to an osmotic effect.⁵ However, erythritol causes more marked inhibition of bacterial growth than sorbitol and xylitol,² likely due to its ability to passively pass through the bacterial cell membrane where it interferes with growth pathways.⁶ The ability of erythritol compared with sorbitol or xylitol to slow the development of dental caries was demonstrated in two three-year studies in children 8 to 9 years old and 14 to 15 years old.^7,8 De Cock et al. concluded that the evidence demonstrates erythritol is more effective than sorbitol or xylitol at maintaining and improving oral health.⁵ In one study, Dr. John Burgess showed a hard candy (Dream Candy) provided significant protection to teeth.⁹

Although they share the same family and have some similar properties, xylitol and erythritol differ in many ways.

Source: Xylitol does not occur naturally and is obtained from birch wood pulp, while erythritol is naturally occurring in many fruits and vegetables; it is commercially obtained by fermenting dextrose from corn, wheat, or fruits.

Taste: Xylitol has a sweetness that is similar to sugar, while erythritol is about 60%–80% as sweet as sugar.

Glycemic index: Xylitol has a glycemic index (GI) of 7, while erythritol has a GI of 0 (zero); as such, it is a better option for diabetics.

Absorption: About 50% of the xylitol consumed is absorbed in the small intestine and metabolized in the liver, while erythritol is rapidly absorbed in the small intestine and excreted in the urine without much change.

Bloodstream: Xylitol is metabolized in the liver into xylose, which is then converted to glucose and released into the bloodstream, while erythritol is metabolized and excreted in the urine unchanged. Consequently, it does not affect the blood glucose or insulin levels.

Digestive effects: Xylitol can cause digestive upset in some people, such as bloating, gas, and diarrhea, while erythritol is generally well tolerated and does not cause digestive problems in most people.

Toxicity: The upper limits of tolerance for erythritol are much higher than xylitol and other polyols.

Maximum dose: Studies have suggested that the maximum dose for xylitol is 0.3 g/kg, while for erythritol it is 0.66 g/kg, which is more than double.¹⁰

Pets: Xylitol can be highly toxic to pets, while erythritol is safe.

Other health benefits: In a study, erythritol showed a considerable radical scavenging activity, antioxidant activity, alpha amylase and glucosidase enzyme inhibition property, improved antioxidant status, and ameliorated blood glucose, HbA1c, and glucose intolerance following diabetes.¹¹

Cost: The net cost of erythritol is higher than xylitol since erythritol is only 60%–80% as sweet; as such, you need to use a lot more of it to get the same level of sweetness.

Conclusion

Both xylitol and erythritol are healthy sugar substitutes. Erythritol is well tolerated, slightly less sweet, and may have some additional health benefits, including being an antioxidant, whereas xylitol can cause digestive upset in some people. Although xylitol is used and referenced extensively for dental products, erythritol may be a better option for many of our patients. The best choice for you depends on your personal preferences and any digestive sensitivities you may have.

Editor's note: This article appeared in the May 2025 print edition of Dental Economics magazine. Dentists in North America are eligible for a complimentary print subscription. Sign up here.