Sugar Alcohols: Xylitol, Diarrhea, Blood Sugar and Labels

Sugar alcohols are sweet carbohydrates such as sorbitol, xylitol, maltitol and erythritol that replace sugar in sugar-free gum, candy, protein bars and many fiber gummies. They carry fewer calories than sugar under FDA labeling rules and raise blood sugar much less, but the body absorbs them poorly, so eating a lot can cause gas, bloating and diarrhea. Despite the name, they contain no alcohol of the drinking kind. Xylitol also has a serious side: it is dangerous for dogs. Here is how each polyol compares, what the research on gut symptoms and heart health shows, and how to spot them on a label.

Peptide Labs sells fiber gummies that contain sugar alcohols, but this article does not recommend any of them. It is general information, not medical advice.

What are sugar alcohols?

For nutrition labeling, the FDA defines sugar alcohols as carbohydrate derivatives in which a hydroxyl group replaces the ketone or aldehyde group of a sugar. In plain terms, they are sugars that have been chemically reduced. Sorbitol, for example, is made by hydrogenating glucose or fructose solutions, according to its FDA regulation. Small amounts occur naturally in certain fruits and vegetables, and they are widely added to sugar-free foods, gum, mints, syrups, chewable vitamins and supplements.

The common ones on US labels are sorbitol, mannitol, xylitol, maltitol, erythritol, isomalt, lactitol and hydrogenated starch hydrolysates (sometimes listed as maltitol syrup or polyglycitol). Xylitol may also be sold as birch sugar or wood sugar, the FDA notes. They are sometimes called polyols, and in diet circles they are the “P” in the low-FODMAP diet.

The calorie column comes from the general factors in the FDA’s Nutrition Facts regulation, which companies may use when they calculate calories. The glycemic index column comes from a 2003 review by Geoffrey Livesey, a nutrition consultant, who pooled published studies; individual responses vary.

Do sugar alcohols raise blood sugar?

Most raise it only a little, and erythritol and mannitol barely at all. In the Livesey review, every polyol fell in the low to very low glycemic range, compared with 65 for table sugar and 100 for glucose. Maltitol and hydrogenated starch hydrolysates had the highest values in the group. So the honest answer to “do sugar alcohols raise blood sugar” is: somewhat, depending on which one and how much.

This matters most for people who manage diabetes. A product labeled sugar free can still contain carbohydrate from sugar alcohols, starch or fiber, and it all counts toward the Total Carbohydrate line. If you track carbohydrate for medical reasons, check that line rather than the front of the pack, and ask your diabetes care team how to count polyols. Our guide on how to stop sugar cravings covers other ways people cut back on sugar.

Sugar alcohols and diarrhea, gas and bloating

The link between sugar alcohols and diarrhea is well documented. Because much of a polyol is not absorbed in the small intestine, it draws water into the gut and reaches the colon, where bacteria ferment it into gas. A 2017 systematic review of 79 studies found that polyols cause flatulence, abdominal discomfort and laxative effects in both healthy people and people with irritable bowel syndrome, and that the effects grow with the amount eaten. Malabsorption also increased when two or more polyols were eaten together, which is common in sugar-free candy. Results in IBS were mixed, and the review called for more research.

FDA rules reflect this. Under 21 CFR 184.1835, any food whose reasonably foreseeable consumption may supply 50 grams of sorbitol a day must say “Excess consumption may have a laxative effect.” For mannitol, the same warning applies at 20 grams a day under 21 CFR 180.25. These are labeling thresholds, not safe-intake targets; many people notice symptoms with far less, especially with IBS.

• Start small: sensitivity varies a lot, so new sugar-free foods are easier to judge one at a time.
• Watch stacking: gum, mints, a protein bar and fiber gummies in the same day add up.
• Fiber plus polyols: many fiber gummies contain both, and either can cause gas; see our guide to fiber supplement side effects.
• Bloating: if you feel puffy after sugar-free snacks, our guide on how to debloat walks through common food triggers.

See a clinician for diarrhea that lasts more than a few days, blood in the stool, weight loss you cannot explain, severe pain or signs of dehydration. Do not assume sweeteners are the cause.

Xylitol: teeth, dogs and the heart research

Xylitol is one of the polyols named in an FDA-authorized health claim (21 CFR 101.80). Foods sweetened with eligible sugar alcohols, which also include sorbitol, mannitol, maltitol, isomalt, lactitol and erythritol, may state that the sweetener does not promote tooth decay, as long as the label also says that frequent between-meal eating of foods high in sugars and starches can promote it. That is why sugar-free gum often carries a tooth-friendly message.

Xylitol is dangerous for dogs

The FDA warns that xylitol does not trigger insulin release in people, but in dogs it can cause a rapid release of insulin and a dangerous drop in blood sugar within 10 to 60 minutes. Signs include vomiting, weakness, staggering, collapse and seizures, and some effects may not appear for 12 to 24 hours. Ferrets are also at risk. Xylitol turns up in gum, mints, baked goods, toothpaste, some peanut and nut butters, chewable vitamins and dietary supplements, including some fiber gummies. If a dog eats a product with xylitol, call a vet, an emergency clinic or an animal poison control center right away.

Xylitol, erythritol and heart health questions

Two studies from the Cleveland Clinic raised questions. In a 2023 Nature Medicine paper, people undergoing heart checkups who had the highest blood erythritol levels had a higher three-year rate of heart attack, stroke or death than those with the lowest levels. A 2024 European Heart Journal paper reported a similar association for xylitol in 2,149 people, and in 10 healthy volunteers a xylitol-sweetened drink raised blood levels sharply and made platelets more reactive in lab tests. These studies show associations in people who already had heart risk factors, and they cannot prove that the sweeteners caused heart events; the authors themselves called for further safety research. The senior author also reported patents and industry ties. If you have heart disease or clotting risks, it is reasonable to ask your clinician about sweeteners.

How to read sugar alcohols on a label

• Total Sugars counts only free mono- and disaccharides, such as glucose and sucrose, so sugar alcohols are not included there.
• Sugar Alcohol is an optional line, but the FDA requires it when the label makes a claim about sugar alcohols, total sugars or added sugars, such as “sugar free”.
• Total Carbohydrate includes sugar alcohols, because it is calculated from everything that is not protein, fat, water or ash.
• Net carbs does not appear in the FDA’s nutrition labeling rules. It is a marketing calculation, and companies do not all subtract polyols the same way.
• Ingredient list: look for names ending in -itol, plus isomalt and hydrogenated starch hydrolysates.

Sugar alcohols in gummy supplements

Sugar-free and no-sugar-added fiber gummies often rely on xylitol or other polyols for sweetness and texture. Two labels we carry show how it looks in practice:

• Vitafusion Fiber Well Fit gummies are sugar free and list 1 gram of sugar alcohol per two-gummy serving, from xylitol, alongside polydextrose fiber and sucralose. The label says to cut back on the daily serving if minor gas or bloating occurs.
• Metamucil Fiber Gummies with Vitamins C, D, B12 have no sugar added and are sweetened in part with xylitol. Their fiber comes from inulin and soluble corn fiber rather than psyllium, and the label suggests new users start slowly.

Because both fiber and polyols can cause gas, it can be hard to tell which one is behind it. Our comparison of Metamucil vs Benefiber explains how psyllium, wheat dextrin and gummy formats differ. If you have a dog at home, store xylitol gummies where it cannot reach them.

Frequently Asked Questions

Questions about a label? Contact us or read our Buyer’s Guide. Follow the label and ask a healthcare provider before starting any supplement, especially if you take medicines. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

Last reviewed October 2026.

Related guides: Erythritol: Side Effects, the Heart Attack Study and Is It Safe?, Fiber Supplement Side Effects: Gas, Choking Risk, Allergies and Medicine Timing, How to Debloat: Common Causes of Bloating, What Helps and When to See a Doctor, Low FODMAP Diet: What FODMAPs Are, FODMAP Foods and the 3 Phases.