Xylitol

Xylitol is the sugar alcohol in sugar-free gum, toothpaste and many keto products, and it is sold as good for your teeth. The tooth benefit is real but small and mostly limited to gum, while people with high blood xylitol have about 1.6 times the risk of a heart attack, stroke or cardiovascular death — a signal backed by lab work on clotting, but not yet by any trial.

Xylitol gum is fine. Using xylitol as a bulk sweetener — in baking, drinks or sugar-free sweets by the handful — is best kept occasional, and avoided if you have heart disease, a past stroke, atrial fibrillation or a high risk of clots (including anyone on antiplatelet drugs). Keep it away from dogs.

What it is

Xylitol is a sugar alcohol (polyol) with a glycemic index of 13, against 65 for table sugar, so it raises blood sugar far less.^[1] It is used in chewing gum, toothpaste, sugar-free sweets and keto baking. It is toxic to dogs.

The heart signal

The Cleveland Clinic group behind the erythritol finding ran the same analysis for xylitol. People in the top third of blood xylitol had about 1.6 times the three-year risk of a heart attack, stroke or cardiovascular death, and in lab experiments xylitol made platelets more prone to clotting.^[2]

In August 2026 the same group reported the link in two general-population cohorts: about 57% more events over six years in a Canadian study of ageing, and about 18% more over 30 years in a study in Norfolk, England. That was a conference presentation with no published confidence ranges, from the same laboratory, so it is pending rather than independent confirmation.^[3]

A separate group found xylitol, along with erythritol and sorbitol, individually linked to faster decline in memory and thinking in a Brazilian study of 12,772 adults, in those under 60 only — a different population and outcome pointing the same way. The paper has since been corrected twice, once after a full re-analysis, so trust the direction more than any single number.^[4]

Where the case is weak

The human platelet study was tiny. Ten people took xylitol, with no placebo group and a single blood draw thirty minutes later. A later editorial argued that design cannot separate a real platelet change from ordinary short-term fluctuation.^[5]
The one trial of regular intake found nothing. Forty-two adults with obesity took 24 g of xylitol (or 36 g of erythritol) a day for five weeks, with no effect on artery stiffness, belly fat or glucose tolerance.^[6]
There is no trial on heart attacks or strokes. The caution rests on plausibility, not demonstrated harm.

Your teeth: a real but oversold benefit

Mouth bacteria can't turn xylitol into the acid that dissolves enamel, so swapping it for sugar helps your teeth. Xylitol is also sold as actively fighting decay, and that part is weaker. A Cochrane review found low-certainty evidence that a xylitol-fluoride toothpaste may cut cavities about 13% compared with fluoride toothpaste alone over 2.5–3 years — resting on two trials from one research group in one population.^[7] Later reviews find xylitol gum helps people at moderate or high risk of cavities, while xylitol sweets don't.^[8]

The gum dose is small and doesn't reach the blood levels behind the platelet effect, which is why the dental use and the cardiovascular caution don't collide.

Your gut

Like most sugar alcohols, xylitol is absorbed slowly and incompletely, and in bulk it ferments in the colon and causes gas, bloating and diarrhoea. EU law requires a laxative warning on any food with more than 10% added sugar alcohols.^[9]

What to do

Chew xylitol gum if you like it, especially if you're prone to cavities. Don't count on it beyond what fluoride toothpaste already does.
Don't use xylitol as an everyday bulk sweetener, and avoid it in that role if you have cardiovascular disease or a high clotting risk, or take antiplatelet drugs.
Store xylitol products out of a dog's reach.
For sweetness without the sugar alcohol signal, stevia and allulose are the better-evidenced options; the full comparison is on Sugar substitutes.