Allulose and erythritol are both low-calorie sweeteners used on keto, but they are different kinds of ingredients. Allulose is a rare sugar that browns, stays soft and dissolves easily. Erythritol is a sugar alcohol that bakes up drier and crisper. Both are a little less sweet than table sugar. Neither is a drop-in replacement for the other in every recipe.
Quick comparison
| Allulose | Erythritol | |
|---|---|---|
| Type | Rare sugar (monosaccharide) | Sugar alcohol |
| Sweetness vs sugar | About 70% (estimate) | About 60 to 70% |
| US label calories | 0.4 kcal per gram | Varies by label; check the product |
| Counted in total carbs? | Yes | Yes |
| Counted in “sugars” line? | FDA allows it to be excluded | No; may appear as sugar alcohol |
| Browning | Browns readily | Browns little |
| Texture in bakes | Soft, moist | Drier, can feel crisp or gritty |
| Common complaint | Over-browning, softness | Cooling taste, recrystallizing |
Sources: FDA allulose labeling update and final guidance; Lakanto help center for erythritol sweetness.
What allulose is, and how it is labeled
Allulose has the same chemical formula as fructose but a different arrangement. The FDA’s final guidance lets manufacturers leave allulose out of the “Total Sugars” and “Added Sugars” lines, but it still counts in Total Carbohydrate. The FDA also allows a label calorie value of 0.4 calories per gram, compared with 4 for sugar (FDA guidance).
Allulose is not simply “undigested.” Much of it is absorbed and then excreted largely unchanged, which is part of why it contributes so few calories. For more background, read our full guide to allulose on keto.
What erythritol is
Erythritol is a sugar alcohol found in small amounts in some fruits and made commercially by fermentation. On US labels it may appear under “Sugar Alcohol” below Total Carbohydrate. Lakanto describes erythritol as about 60 to 70% as sweet as sugar (Lakanto help center).
Brand blends: read the bag, not the name
Many sweeteners on store shelves are blends. For example, Lakanto Classic combines monk fruit extract and erythritol and is designed to measure cup-for-cup like sugar. That is very different from pure monk fruit extract, which is far more concentrated and used in tiny amounts.
Because blends differ, there is no universal “monk fruit to sugar” ratio. Practical steps:
- Read the ingredient list. The first ingredient is usually the bulk sweetener (erythritol or allulose).
- Look for the brand’s own measuring guidance, such as “cup for cup” or “use half.”
- Use our sweetener converter as a starting point, then follow the brand’s instructions when they differ.
Baking behavior
These differences are described in Wholesome Yum’s pure-allulose product guidance and Icon Foods’ baking application sheet. They are ingredient guidance from manufacturers, rather than results from our own recipe testing.
Browning. Allulose takes part in browning reactions, so baked goods can darken faster than with sugar. Watch the color, and consider tenting with foil or following a recipe written for allulose. Erythritol browns very little, so bakes can look pale.
Moisture and texture. Allulose tends to keep cookies and cakes soft. That is useful for sauces, caramel and ice cream, less useful when you want a crisp cookie. Erythritol produces a drier, crisper result and can recrystallize as it cools, which some people notice as grit.
Taste. Many people notice a cooling sensation with erythritol, similar to mint without the flavor. Allulose tastes closer to plain sugar to many people.
Blending. Some home bakers combine the two to balance browning, softness and cooling. If you try that, change one variable at a time and note the results.
Label arithmetic
Net carbs on keto are usually calculated as total carbs minus fiber, and many people also subtract sugar alcohols and allulose. Labels do not always make that easy. Here is a hypothetical example to show the math:
| Label line (hypothetical bar) | Grams |
|---|---|
| Total Carbohydrate | 20g |
| Dietary Fiber | 9g |
| Total Sugars | 1g |
| Sugar Alcohol (erythritol) | 6g |
| Allulose (listed on a separate line) | 4g |
- Total carbs minus fiber: 20 minus 9 = 11g
- Also subtracting erythritol: 11 minus 6 = 5g
- Also subtracting allulose: 5 minus 4 = 1g
If the label does not list allulose separately, you cannot tell how much of the total carbs it accounts for. In that case, count the higher number. Run your own label through our net carbs calculator.
Also check the serving size. A sweetener packet or small spoonful may show 0 calories because of rounding, even though larger amounts add up.
Which should you choose?
- Pick allulose for sauces, syrups, caramel, frozen desserts and soft baked goods.
- Pick erythritol or an erythritol blend for crisp cookies, or when a recipe was developed with it.
- Pick the one your recipe was written for when in doubt.
Tolerance varies. Large amounts of either can cause digestive discomfort in some people, so start with modest portions. For a wider look at options, see our keto sugar substitutes guide.