Do Sweeteners Raise Blood Sugar? Allulose vs Sugar Alcohols

“Blood drop, sugar cubes and a stevia leaf illustrating whether sweeteners raise blood sugar

It depends on the sweetener, and just as often on the food it is sitting in. Artificial sweeteners such as aspartame, sucralose and stevia do not directly raise blood sugar. Sugar alcohols can, and by very different amounts: maltitol has a far bigger effect than erythritol. Allulose has the cleanest blood sugar record of the group. But a "sugar-free" label never guarantees a flat glucose curve, and this guide shows why.

Key Takeaways

Allulose offers the most favorable glycemic profile, while different sugar alcohols vary widely from zero impact (erythritol) to significant glucose elevation (maltitol).
Non-nutritive sweeteners do not cause a direct glucose spike, though individual glycemic responses can still be influenced by gut microbiome shifts or co-ingested ingredients.
"Sugar-free" does not mean carbohydrate-free or calorie-free; always check the ingredient list and total carbohydrate count rather than relying on front-of-pack claims.

Quick comparison: which sweeteners raise blood sugar?

Glycemic index (GI) figures below come from a published review of sugar alcohols, where table sugar (sucrose) scores 69. Exact values differ a little between studies, but the order stays the same.

Sweetener	Type	Effect on blood sugar	Watch out for
Allulose	Rare sugar	Minimal. Trials in type 2 diabetes link it to lower post-meal glucose	Long-term data is still limited
Erythritol	Sugar alcohol	GI about 0	Heart-health signal in observational and small platelet studies
Xylitol	Sugar alcohol	GI about 13	Digestive upset in larger amounts
Sorbitol / mannitol	Sugar alcohol	GI about 9 / 0	Digestive upset in larger amounts
Maltitol	Sugar alcohol	GI about 35, the highest of the common ones	Used in some "sugar-free" sweets and chocolate
Aspartame, stevia	Non-nutritive	No direct rise; no significant effect on glucose tolerance in one major trial	Other ingredients in the product
Sucralose, saccharin	Non-nutritive	No direct rise; impaired glucose tolerance in one 2-week trial of healthy adults	Effect varies from person to person

Allulose: the closest thing to a blood-sugar-neutral sugar

Allulose is a rare sugar found in small amounts in some fruits, with a structure similar to fructose. Unlike regular sugar, the body does not significantly metabolise it, so it adds few calories and has a negligible effect on blood glucose and insulin. To maintain overall metabolic stability when managing daily nutrition, pairing sweet foods thoughtfully as part of a low-glycemic meal prep routine helps flatten overall glucose responses.

The clinical evidence is encouraging. A 2024 meta-analysis pooled six randomised trials (126 people with type 2 diabetes) and found that allulose significantly reduced post-meal glucose and the time spent above the target glucose range. Fasting glucose did not change significantly, and the authors say longer-term research is still needed. Six small trials is a useful signal, not a final verdict.

One label detail matters here. The FDA has said it will not object if allulose is left out of the "Total Sugars" and "Added Sugars" numbers, and it accepts a figure of 0.4 calories per gram instead of 4. But allulose still has to be included in Total Carbohydrate. So a bar that says "1 g sugar" can still contain meaningful allulose, and the ingredient list is the only place that shows it.

Sugar alcohols: same family, very different effects

Sugar alcohols (also called polyols) are carbohydrates that the body only partly absorbs. Mayo Clinic notes that, unlike other sweeteners, they can raise blood sugar. Diabetes UK adds that they contain carbohydrate and calories, though fewer than sugar, and that it is not exactly clear how people who dose insulin by carbohydrate should count them.

Erythritol and mannitol: GI of about 0, the lowest effect on glucose.
Sorbitol, xylitol, isomalt, lactitol: low GIs, roughly 6 to 13 in the review table.
Maltitol: GI of about 35. That is still half of sugar, but it is the one most likely to show up on a glucose meter.

Large amounts of polyols can also have a laxative effect, causing bloating, gas and diarrhoea, according to Diabetes UK.

The erythritol question

Erythritol is popular in keto and "zero sugar" products because of its zero glycemic index, but its heart-health record is under review. A 2023 Nature Medicine study found that people with the highest blood erythritol levels (top 25%) were about twice as likely to have a heart attack, stroke or death over three years as those with the lowest. A follow-up study in healthy volunteers found that a typical serving of erythritol, but not glucose, made platelets more reactive, which could raise clotting risk.

These findings do not prove that eating erythritol causes heart attacks. The first study was observational and the platelet study measured a short-term lab effect. They are good reasons to treat large daily servings with caution, especially if you already have heart disease risk factors.

Artificial sweeteners: no direct spike, but not necessarily inert

Mayo Clinic's position is straightforward: artificial sweeteners, including aspartame, sucralose, saccharin, stevia and monk fruit, do not affect blood sugar directly. Used instead of sugar, they cut carbohydrate and calories.

The more complicated question is whether they change how your body handles glucose indirectly. A 2022 randomised trial published in Cell gave 120 healthy adults saccharin, sucralose, aspartame or stevia for two weeks, at doses below the acceptable daily intake. Saccharin and sucralose significantly impaired glucose tolerance, while aspartame and stevia did not. The changes were linked to shifts in gut bacteria, differed a lot from person to person, and faded after the sweeteners were stopped. Exploring how your microbiome interacts with food components can be further understood through a targeted gut microbiome and incretin hormone guide.

Independent experts also pointed out limits: the groups were small, the volunteers were healthy and had avoided sweeteners for six months, and the trial lasted only two weeks. It does not show that these sweeteners are worse than sugar.

The World Health Organization took a cautious line in 2023. It issued a conditional recommendation against using non-sugar sweeteners for weight control or to reduce the risk of non-communicable diseases. A BMJ analysis noted that the guideline did not cover people with diabetes, who often use these sweeteners to manage blood glucose.

The bigger catch: the food around the sweetener

The sweetener is often not what raises your glucose. A dietitian quoted by Houston Methodist explains the point well: anything with calories, whether from carbohydrate, protein or fat, can raise blood sugar, just by different amounts. A sugar-free cake still contains flour and usually a lot of fat, and keto-style products often add fat to make up for the missing sugar. Understanding how macronutrients interact with blood glucose can be supported by adopting a structured macro tracking framework for beginners.

Diabetes UK makes a similar warning about foods sold as "diabetic" or "suitable for diabetics": they can be as high in fat and calories as standard products, so it does not recommend them. It also reminds readers that "sugar-free" does not mean low-calorie.

How to read a "sugar-free" label in 60 seconds

Check the ingredient list first. Look for allulose, maltitol, erythritol or other "-ol" words. The sugar line alone will not show them.
Compare Total Carbohydrate, not just sugar. Allulose is left out of Total Sugars but still counts as carbohydrate.
Spot maltitol early. If it is high on the list in chocolate, bars or sweets, expect more of a glucose rise than with erythritol.
Look at the base food. Refined flour, starch and fat can raise glucose regardless of the sweetener.
Remember tabletop sachets. Some are bulked out with other ingredients. In the Cell trial, the sweetener sachets were bulked with glucose.

Practical rules for steadier blood sugar

Use sweeteners to replace sugar, not to justify extra portions of the same dessert.
Pair sweet foods with protein, fibre or fat from whole foods rather than eating them alone. Incorporating smart food sequencing principles—such as those found in a guide to flattening blood sugar spikes through food sequencing—can further blunt any post-meal glucose response.
If you wear a glucose monitor or test with a meter, check your own response. Individual reactions to sweeteners vary.
Start with small amounts of sugar alcohols and build up slowly to avoid digestive upset.
If you have diabetes or take glucose-lowering medicines, ask your healthcare team before changing your sweetener routine.

Frequently Asked Questions

Does allulose raise blood sugar?

Not meaningfully. The body does not significantly metabolise it, and a meta-analysis of six trials in type 2 diabetes found lower post-meal glucose with allulose. It still counts as a carbohydrate on the label.

Do artificial sweeteners raise blood sugar?

Not directly, according to Mayo Clinic. Some research, such as the 2022 Cell trial, suggests saccharin and sucralose may affect glucose tolerance in some people, but that evidence is short-term and limited to healthy adults.

Does sugar alcohol raise blood sugar?

It can, but by much less than sugar. Erythritol is close to zero, maltitol is the highest of the common ones at about half the GI of sugar.

What is the best sweetener for blood sugar?

There is no single winner. Erythritol and allulose have the lowest direct glucose effect, and aspartame and stevia showed no significant effect in the Cell trial, but each has its own caveat. The best choice is the one that keeps your total intake of sweeteners and sweet foods modest and that you tolerate well.

Is "sugar-free" the same as low-carb?

No. Sugar-free products can still contain starch, flour, sugar alcohols and fat. Always read Total Carbohydrate and the ingredient list.

The bottom line

For blood sugar, allulose, erythritol, stevia and aspartame have the least direct impact, maltitol has the most among the common sweeteners, and saccharin and sucralose carry a question mark for some people. But the food around the sweetener usually matters more than the sweetener itself, so read the whole label rather than the "sugar-free" claim.

Disclaimer: this article is for general information and is not medical advice. If you have diabetes, prediabetes or a heart condition, talk to your doctor or dietitian before changing what you eat.