Xylitol vs Erythritol

First, if there is a dog in the house: xylitol is life-threatening to dogs. In dogs it triggers a large insulin release and a dangerous drop in blood sugar within 10 to 60 minutes, and serious effects can be delayed 12 to 24 hours, so a dog that seems fine still needs a vet. It is also sold as birch sugar or wood sugar, and turns up in gum, mints, sugar-free candy, baked goods, some nut butters and toothpaste. Erythritol carries no such warning in our record. For a household with a dog, that settles the choice before anything below.

Beyond that, xylitol and erythritol are the two sugar alcohols people actually choose between, and they are less alike than the shared label suggests. Xylitol tastes about as sweet as sugar and carries real calories; erythritol is noticeably less sweet and is the only sugar alcohol with a zero calorie factor. Xylitol has the better-supported benefit, for teeth. Both carry an open cardiovascular question.

At a Glance

Every row below comes from our two sourced records, the same ones the cards at the foot of this page show. Each figure links to the document it came from and the date we last checked it; open “Note” for the qualifications that go with it. Where a record has nothing sourced for a row, the cell says so rather than filling the gap.

Sweetness and Calories

In a sensory study that compared 16 sweeteners, xylitol matched sugar almost exactly, at 98–112% of sugar’s sweetness across the concentrations tested, slightly sweeter at the highest. That is one panel’s measurement rather than an official specification, but it means xylitol can replace sugar by weight. Erythritol’s specification band is 60–80% of sugar’s sweetness, so a weight-for-weight swap under-sweetens.

The calorie gap is wide. FDA assigns xylitol 2.4 kcal/g, the highest of the sugar alcohols it lists and 60% of sugar’s 4 kcal/g. It assigns erythritol 0, the only sugar alcohol at zero. “Sugar alcohol” is not one low-calorie category.

Net Carbs and Blood Sugar

Erythritol’s glycemic index is 0, averaged across four studies, and it subtracts in full from net carbs. Our xylitol record has no sourced glycemic index, so it takes a deliberately conservative line: half of xylitol’s grams still count. Xylitol carries real metabolizable energy, and we would rather over-count than under-report carbohydrate to someone managing diabetes. That will be revisited when a glycemic index can be sourced.

On a US label, both count in Total Carbohydrate and neither counts in Total Sugars.

Teeth

Xylitol’s specific benefit is dental. A systematic review of controlled trials found xylitol gum lowered mutans streptococci counts in 12 of 14 studies, reduced plaque in 6 of 10 and reduced cavities in 3 of 5. The comparison was against sorbitol gum, not against no gum, so some of the effect is chewing, and xylitol is an addition to brushing, fluoride and dental care, not a substitute. Our erythritol record makes no dental claim.

Digestion and Texture

EFSA pooled ten human studies of erythritol and found diarrhea thresholds of 0.5–1 g per kg of body weight in a single dose. In 2023 it set erythritol’s acceptable daily intake at 0.5 g/kg a day, found children’s high intakes already exceed it, and kept the EU laxative warning on foods with more than 10% erythritol. Our xylitol record has no sourced tolerance figure, so we do not give one here.

In the kitchen, erythritol does not brown, has the strongest cooling effect of the common sugar alcohols, and recrystallizes as foods cool, which leaves a gritty texture. Our xylitol record has no sourced figures on browning, cooling or recrystallization, so this page does not compare them.

The Cardiovascular Question

Both polyols have the same kind of open question, and it should be stated plainly for both.

For xylitol: a 2024 study in the European Heart Journal found that people in the top third of blood xylitol had a higher risk of major adverse cardiovascular events (adjusted HR 1.57 in a validation cohort of 2,149), along with lab findings that xylitol made platelets more reactive. Larger data presented at the ESC Congress in August 2026, from two cohorts totaling 17,710 people, found higher risk in the top quarter of blood xylitol in both (adjusted HR 1.47 and 1.18). Those data are conference-stage and not yet peer-reviewed.

For erythritol: a 2023 study in Nature Medicine linked higher blood erythritol to a higher risk of major adverse cardiac events; the ARIC study linked it to heart-failure hospitalization, cardiovascular death and death from any cause; and three genetic studies published in 2025 and 2026 found higher genetically predicted erythritol going with higher odds of stroke or coronary disease.

The caveats apply to both. These studies measure the sweetener in the blood, not in the diet, and the body makes both itself: roughly 5–15 g of xylitol a day, and erythritol from glucose. In the Nurses’ Health Study, the same size of association showed up for mannitol and sorbitol, polyols almost nobody eats in quantity, which is what a shared metabolic explanation would look like; the erythritol association also faded once diabetes was accounted for. A 2025 review that concluded causation is lacking noted patients given up to 120 g a day of intravenous xylitol without attributable harm, though that review carries an industry conflict. Neither sweetener has been restricted by a regulator. Neither signal is settled.

Regulatory Status

Both are authorized in the EU under the same group authorization for polyols: xylitol as E 967, erythritol as E 968. In the US, xylitol is a permitted sugar alcohol named in FDA’s labeling rules, and erythritol is GRAS by notification, with six FDA “no questions” letters between 2001 and 2026.

Which Should You Choose

If there is a dog in the home, choose erythritol, or keep xylitol products where a dog cannot reach them under any circumstances. For teeth, xylitol gum or mints have the trial evidence. For replacing sugar by weight, xylitol’s sweetness is the closer match, at the cost of 2.4 kcal/g. For the fewest calories and carbs, erythritol, within its daily limit.

The Bottom Line

Xylitol is a sugar reducer rather than a sugar eliminator: as sweet as sugar, 60% of its calories, the only sweetener we cover with a specific, trial-supported benefit (dental, as an adjunct), and a household hazard for dogs. Erythritol is the zero-calorie, zero-GI option, with a digestive limit lower than most people assume. Both carry a cardiovascular association measured in the blood, not yet shown to come from diet, and worth knowing about if you already have heart risk factors.