Sugar alcohols are a type of carbohydrate used as sweeteners in thousands of “sugar-free” and “no sugar added” products. Despite the name, they contain no ethanol and won’t make you intoxicated. Their chemical structure simply shares features with both sugar molecules and alcohol molecules, which is how they got the confusing name. You’ll find them in sugar-free gum, candy, ice cream, baked goods, and even toothpaste.
How Sugar Alcohols Differ From Sugar
Regular table sugar (sucrose) is fully absorbed in the small intestine, hits your bloodstream fast, and delivers about 4 calories per gram. Sugar alcohols take a different path. Your body only partially absorbs most of them, which means they provide fewer calories (roughly 0.2 to 3 calories per gram, depending on the type) and raise blood sugar far less dramatically.
The most common sugar alcohols you’ll see on ingredient labels are erythritol, xylitol, sorbitol, maltitol, mannitol, isomalt, and lactitol. Each one varies in sweetness, calorie content, and how your body handles it. None of them taste quite as sweet as sugar, gram for gram, though xylitol comes close at about 97% of sugar’s sweetness. Maltitol sits at roughly 87%, while others like lactitol and mannitol deliver only about a third to half the sweetness of sugar.
Where They Come From
Sugar alcohols aren’t purely synthetic. Many occur naturally in fruits and vegetables. Sorbitol is found in various fruits and is commercially manufactured from corn syrup. Mannitol shows up naturally in pineapples, olives, asparagus, sweet potatoes, and carrots, and is extracted from seaweed for food manufacturing. Xylitol, sometimes called “wood sugar,” occurs naturally in straw, corncobs, mushrooms, and several cereals and fruits.
For commercial use, these compounds are produced at industrial scale, typically by chemically modifying sugars derived from corn, wheat, or other plant starches.
Blood Sugar and Calorie Impact
This is the main reason sugar alcohols exist in so many products. Their effect on blood sugar is dramatically lower than regular sugar. Table sugar has a glycemic index (GI) of 65. For comparison, here’s how common sugar alcohols stack up:
- Erythritol: GI of 1
- Mannitol: GI of 2
- Isomalt: GI of 2
- Lactitol: GI of 3
- Sorbitol: GI of 4
- Xylitol: GI of 12
- Maltitol: GI of 35
Most of these barely register on the blood sugar scale. Even maltitol, the highest of the group, still sits at roughly half the GI of table sugar. This makes sugar alcohols a popular choice for people managing diabetes or trying to reduce blood sugar spikes.
One thing to be aware of: food packaging often uses the term “net carbs,” calculated by subtracting fiber and sugar alcohols from total carbohydrates. The FDA does not officially recognize this term, and the American Diabetes Association does not use it either. The assumption behind “net carbs” is that sugar alcohols aren’t absorbed or metabolized, but that’s not entirely accurate. Some are partially digested and still provide calories and some blood sugar impact. The FDA recommends using the total carbohydrate count on the nutrition facts label as your guide.
Digestive Side Effects
The same incomplete absorption that keeps sugar alcohols from spiking your blood sugar is also what causes their most common downside: digestive discomfort. When sugar alcohols aren’t fully absorbed in the small intestine, they travel to the large intestine, where they draw water in through an osmotic effect and get fermented by gut bacteria. The result can be gas, bloating, abdominal cramps, and diarrhea.
These symptoms are dose-dependent. A stick of xylitol gum is unlikely to cause trouble, but eating a whole bag of sugar-free candy in one sitting is a well-known recipe for stomach distress. Combining multiple types of sugar alcohols in one meal can make malabsorption worse. People with irritable bowel syndrome (IBS) tend to be more sensitive to these effects.
Erythritol is the notable exception. About 90% of it gets absorbed in the small intestine before it ever reaches the colon, so very little is left to cause osmotic effects or gas production. That’s why erythritol is generally the best-tolerated sugar alcohol and has become especially popular in low-carb and keto products.
Dental Benefits
Unlike regular sugar, sugar alcohols don’t feed the bacteria responsible for tooth decay. Xylitol goes a step further: it actively inhibits the growth of cavity-causing bacteria. These bacteria (Streptococcus mutans) cannot use xylitol as a fuel source, so when xylitol replaces sugar in your mouth, the bacterial population gradually shifts. Less plaque forms, and the level of acids attacking tooth enamel drops. This is why xylitol appears in so many sugar-free gums and mints, and why some dentists specifically recommend xylitol-containing products for cavity prevention.
Erythritol and Heart Health Concerns
A 2023 study highlighted by the National Institutes of Health raised questions about erythritol specifically. Researchers found that people with the highest blood levels of erythritol were about twice as likely to experience cardiovascular events over three years compared to those with the lowest levels. In lab experiments, exposing human platelets to erythritol increased their sensitivity to clotting signals. In mice, elevated erythritol levels sped up blood clot formation and artery blockage.
When healthy volunteers consumed erythritol, their blood levels of the sweetener rose 1,000-fold and stayed substantially elevated for several days. For at least two days, those levels were high enough to trigger changes in platelet function. The findings suggest that consuming erythritol could increase blood clot formation, which could in turn raise the risk of heart attack or stroke. This research is still being evaluated, and it doesn’t mean erythritol is definitively dangerous, but it’s worth knowing about, particularly if you consume erythritol-sweetened products regularly and have existing cardiovascular risk factors.
Xylitol Is Toxic to Dogs
This is one of the most important things to know about sugar alcohols if you have pets. Xylitol is extremely dangerous for dogs. In most mammals, xylitol has no notable effect on insulin, but in dogs it triggers a rapid, dose-dependent insulin release that can cause life-threatening drops in blood sugar. At higher doses, it can cause severe liver failure. Even a small amount of xylitol from a few pieces of sugar-free gum can be enough to poison a small dog. If your dog gets into anything containing xylitol, it’s a veterinary emergency. Keep xylitol-containing gum, candy, peanut butter, and baked goods well out of reach.