Sugar alcohols are a type of sweetener used in candy labeled “sugar-free” or “no sugar added.” Despite the name, they contain no ethanol (the alcohol in drinks) and aren’t exactly sugar either. They’re a category of carbohydrate called polyols, created by chemically modifying sugars so your body absorbs them differently. The result is a sweetener with fewer calories, a smaller blood sugar spike, and a distinct cooling sensation in your mouth.
Why They’re Called “Sugar Alcohols”
The name comes from chemistry, not from anything you’d find at a bar. Sugar alcohols have a molecular structure that resembles both a sugar and an alcohol at the atomic level, with a specific arrangement of hydrogen and oxygen atoms. But they behave nothing like either one. They don’t ferment into ethanol, and your body doesn’t process them the way it processes table sugar. Think of it as an unfortunate naming convention that confuses nearly everyone who reads a candy wrapper.
Common Types Found in Candy
Walk down the sugar-free candy aisle and you’ll see a handful of these ingredients appearing again and again:
- Maltitol is the most popular sugar alcohol in candy. It’s about 75% as sweet as regular sugar and gives chocolate and hard candies a creamy texture, which is why it dominates sugar-free chocolate bars and baked goods.
- Sorbitol occurs naturally in apples, pears, and peaches, though the version in candy is typically manufactured from corn syrup. It’s only 50% as sweet as sugar, so manufacturers need to use roughly twice as much to get a comparable sweetness.
- Xylitol matches the sweetness of regular sugar one-to-one. It’s most common in chewing gum and mints. Sometimes called “wood sugar,” it can be derived from corncobs, straw, and birch bark.
- Erythritol is the least sweet of the group, at roughly 60 to 80% of sugar’s sweetness. It occurs naturally in small amounts in fruits, mushrooms, and fermented foods like wine and soy sauce.
- Isomalt shows up frequently in hard candies and lollipops, especially artisan or decorative ones, because it resists crystallization and stays clear when melted.
How Your Body Processes Them
Regular sugar gets absorbed quickly and completely in your small intestine, sending glucose straight into your bloodstream. Sugar alcohols take a different path. Your small intestine absorbs them only partially. Research on sorbitol, for example, shows that roughly 64 to 79% gets absorbed in the small intestine depending on what else you’ve eaten. Whatever isn’t absorbed travels to the large intestine, where gut bacteria ferment it.
This partial absorption is exactly why sugar alcohols have fewer calories. The FDA assigns specific calorie values to each one: erythritol counts as 0 calories per gram, mannitol at 1.6, isomalt and lactitol at 2.0, maltitol at 2.1, xylitol at 2.4, and sorbitol at 2.6. Compare that to regular sugar at 4 calories per gram. Erythritol is the outlier because about 90% of it is absorbed in the small intestine and then excreted unchanged in urine, so your body extracts essentially no energy from it.
Blood Sugar and Glycemic Impact
One of the main reasons sugar alcohols end up in candy is their effect on blood sugar. Regular table sugar has a glycemic index of 65, meaning it raises blood glucose substantially. Xylitol’s glycemic index is just 12. Erythritol’s is near zero. This makes sugar-free candy a more manageable option for people monitoring their blood sugar, though it doesn’t make these products carbohydrate-free. Sugar alcohols still count under “Total Carbohydrate” on the nutrition label.
The Cooling Sensation
If you’ve ever eaten a sugar-free mint or hard candy and noticed an almost icy feeling on your tongue, that’s not menthol. Sugar alcohols absorb heat when they dissolve in your mouth, creating a genuine cooling effect. Erythritol and xylitol produce this sensation most noticeably. Candy makers sometimes use this property intentionally, and it also helps mask off-flavors that can come from other sugar-free ingredients.
Why They’re Better for Your Teeth
Sugar alcohols don’t cause cavities. The bacteria responsible for tooth decay, primarily Streptococcus mutans, feed on regular sugar and produce acid that erodes enamel. They can’t ferment sugar alcohols the same way. Xylitol goes a step further: the bacteria actually absorb it, mistaking it for a usable sugar, but once inside the cell, the xylitol gets trapped in a cycle that wastes the bacteria’s energy without producing anything useful. The bacteria essentially starve themselves trying to process it. This is why xylitol-sweetened gum is specifically recommended by many dental organizations.
Digestive Side Effects
The portion of sugar alcohol that reaches your large intestine undigested gets fermented by gut bacteria, producing gas and drawing water into the bowel. The result, for many people, is bloating, cramping, and diarrhea. You may have noticed that sugar-free candy bags carry a warning about “laxative effects,” and it’s not a joke.
How much it takes to trigger symptoms varies by the specific sugar alcohol and by the person. Sorbitol has one of the lowest thresholds: as little as 0.17 grams per kilogram of body weight for men and 0.24 grams per kilogram for women can cause diarrhea. For a 150-pound person, that’s roughly 12 to 16 grams of sorbitol, an amount easily found in a small bag of sugar-free gummy bears. Erythritol is far more forgiving, with laxative thresholds around 0.66 to 0.80 grams per kilogram of body weight, roughly 45 to 55 grams for the same person. Your tolerance also improves with repeated exposure, so occasional consumers are more likely to have trouble than regular ones.
Reading the Label
Under FDA rules, sugar alcohols are listed under “Total Carbohydrate” on the Nutrition Facts panel, but their specific gram amount is voluntary unless the product makes a claim about sugar content. If the packaging says “sugar-free” or highlights the sugar alcohol in any way, the grams of sugar alcohol must be declared separately, indented below total carbohydrate. They are not counted under “Total Sugars” because they’re chemically distinct from sugars like glucose, fructose, and sucrose. This means a candy can legitimately say “0g Total Sugars” while still containing significant carbohydrates from sugar alcohols.
Erythritol and Heart Health Concerns
Erythritol has drawn attention in recent cardiovascular research. Studies have found that higher blood levels of erythritol are associated with increased risk of major cardiovascular events, including heart attack and stroke. One study in a cohort of men found that elevated serum erythritol was linked to a 50% higher risk of overall mortality and an 86% higher risk of cardiovascular disease mortality after adjusting for other factors. Lab research suggests a possible mechanism: erythritol appears to make blood platelets more reactive and prone to clotting, and blood levels stay elevated for at least two days after consuming an erythritol-sweetened drink.
This research is still evolving, and the amounts consumed in studies often exceed what you’d get from a few pieces of candy. But if erythritol appears high on the ingredients list of products you consume daily, it’s worth being aware of.
Xylitol Is Toxic to Dogs
If you have a dog, this is the most important thing to know about sugar alcohols. Xylitol is extremely dangerous for dogs. A dose as low as 0.1 grams per kilogram of body weight can cause a dangerous drop in blood sugar, and doses above 0.5 grams per kilogram can trigger acute liver failure. For a 20-pound dog, that’s less than a gram to cause hypoglycemia, an amount found in a single piece of some sugar-free gums. Dogs that develop liver failure from xylitol have a poor prognosis. Keep all xylitol-containing candy, gum, and mints completely out of reach.