The best keto sweeteners are allulose, erythritol, and monk fruit, all of which have 0 net carbs and a glycemic index of 0, so they do not raise blood sugar or break ketosis. Allulose is about 70% as sweet as sugar and caramelizes like the real thing, erythritol is roughly 70% as sweet and the cheapest to buy, and monk fruit is 100 to 250 times sweeter than sugar, so it is almost always sold in a 1:1 blend with erythritol or allulose. Stevia rounds out the zero-carb group but carries a bitter edge. The rest of this guide covers how each one bakes, a conversion cheat sheet, and the marketing traps (maltitol, “natural” sugars, and hidden bulking agents) that quietly spike blood sugar.
Keto sweetener comparison table
Net carbs and glycemic index are what decide whether a sweetener fits keto. Use our net carbs calculator to check any label yourself.
| Sweetener | Sweetness vs sugar | Net carbs | Glycemic index | Baking behavior | Aftertaste |
|---|---|---|---|---|---|
| Allulose | ~70% | 0g | 0 | Browns, caramelizes, keeps things soft, no crystallizing | Clean, none |
| Erythritol | ~70% | 0g | 0-1 | Crystallizes and recrystallizes, does not brown, cooling effect | Cooling, faint |
| Monk fruit blend | 1:1 (blended) | 0g | 0 | Behaves like its carrier (erythritol or allulose) | Slight fruity note |
| Stevia | 200-350x | 0g | 0 | No bulk or browning, needs a filler to bake | Bitter, licorice-like |
| Xylitol | ~1:1 | ~3-4g per tsp | 7-13 | Browns lightly, cooling effect, bakes near 1:1 | Minimal, toxic to dogs |
| Tagatose | ~90% | ~1.5g per tsp | 3 | Browns and caramelizes well | Minimal |
| Sucralose (Splenda) | 600x pure | 0g pure, ~24g/cup bagged | 0 pure | Bulked version bakes, can turn bitter at high heat | Slight, can be metallic |
| Aspartame | ~200x | ~0g | 0 | Breaks down with heat, not for baking | Slight |
| Maltitol | ~90% | Counts, high | 35-52 | Browns and bakes like sugar | Minimal, but spikes blood sugar |
| Honey | ~1.3x | ~17g per tbsp | 58 | Bakes and browns, but not keto | None |
| Maple syrup | ~0.9x | ~13g per tbsp | 54 | Bakes, but not keto | None |
| Agave | ~1.4x | ~15g per tbsp | 15 | Low GI but very high carb, not keto | None |
| Coconut sugar | ~1:1 | ~4g per tsp | 54 | Bakes like brown sugar, but not keto | Caramel note |
The three best keto sweeteners
Allulose
Allulose is a rare sugar that your body does not metabolize for energy, so it delivers a clean, sugar-like taste with 0 net carbs and a glycemic index of 0. It is about 70% as sweet as table sugar, which means you use a little more to match. What sets allulose apart is how it behaves in the kitchen: it browns and caramelizes, holds moisture, and lowers the freezing point of anything you make, which is why it is the single best choice for keto ice cream, syrups, caramel, and soft, chewy cookies that would go rock-hard with erythritol. It also dissolves fully, so it will not leave grit in cold drinks. Small human studies even suggest it may slightly blunt the blood sugar rise from a meal. For the full breakdown, see our guide to allulose on keto.
Where it shines: syrups, caramel, ice cream, brownies, anything that should stay soft.
Erythritol
Erythritol is the workhorse of keto baking and the cheapest sweetener to buy in bulk. It is a sugar alcohol that is absorbed but not metabolized, so it passes through with 0 net carbs and a glycemic index of essentially 0. At about 70% the sweetness of sugar, it measures much like allulose. Its two quirks are worth knowing. First, it produces a distinct cooling sensation on the tongue, similar to mint, that stands out in frostings and no-bake recipes. Second, it recrystallizes as baked goods cool, which can leave a gritty or crunchy texture in soft cookies and cakes. Grinding it to a powder first, or blending it with allulose, largely fixes both problems. It is the most widely stocked keto sweetener and forms the base of most monk fruit blends like Swerve and Lakanto Classic.
Where it shines: crisp cookies, cheesecakes, budget baking, granulated blends.
Monk fruit
Monk fruit extract comes from a small gourd and is 100 to 250 times sweeter than sugar, with 0 net carbs and no glycemic impact. Because it is so concentrated, a pure extract is impractical to bake or measure with, so nearly every granulated “monk fruit sweetener” on the shelf is really erythritol or allulose carrying a small amount of monk fruit extract for sweetness. Read as a blend, monk fruit’s job is flavor: it has no cooling effect of its own and no digestive downside, so it softens the harsher notes of the bulking sweetener it rides on. A monk fruit and allulose blend is the closest thing to a true 1:1 sugar replacement that browns, stays soft, and has no aftertaste. Our monk fruit on keto article goes deeper on the extract itself.
Where it shines: as the flavor half of a 1:1 granulated blend for everyday baking.
Baking conversion cheat sheet
Because most keto sweeteners are less sweet by volume than sugar (or wildly more sweet, in the case of extracts), you cannot swap them blind. Here is what replaces 1 cup of sugar.
| To replace 1 cup sugar | Use |
|---|---|
| Allulose | 1 1/3 cups |
| Erythritol | 1 1/3 cups |
| Monk fruit + erythritol blend (1:1) | 1 cup |
| Monk fruit + allulose blend (1:1) | 1 cup |
| Xylitol | 1 cup |
| Pure stevia extract | 1 tsp (or check the package) |
| Pure monk fruit extract | 1/2 to 1 tsp (check the package) |
Two rules save most keto bakes. Powder your granulated sweetener in a blender before making frostings, glazes, or anything no-bake, so it dissolves instead of turning gritty. And when a recipe depends on sugar staying soft or caramelizing, such as brownies or salted caramel, reach for allulose rather than erythritol, because erythritol recrystallizes hard as it cools. Sweeteners do nothing for structure, so pair them with the right base from our low carb flour guide.
Sweeteners that spike blood sugar despite the marketing
Maltitol, the sugar-free trap
Maltitol is the most misleading sweetener on the shelf. It is a sugar alcohol, so products made with it are legally labeled “sugar-free,” and it appears in a huge share of sugar-free candy, chocolate, and protein bars. But unlike erythritol, maltitol is largely metabolized. Its glycemic index sits around 35 to 52, roughly half that of table sugar, which means a “sugar-free” chocolate bar sweetened with maltitol can still raise your blood glucose and stall ketosis. It also counts toward net carbs: you cannot subtract maltitol the way you subtract erythritol. If a keto bar or candy lists maltitol high in the ingredients, treat it as a partial sugar, not a free food.
Honey, maple, agave, and coconut sugar
These get marketed as natural or healthy, but on keto they behave like sugar because they are sugar. Honey runs about 17g net carbs per tablespoon with a glycemic index of 58. Maple syrup is roughly 13g per tablespoon at GI 54. Coconut sugar is around 4g per teaspoon, and despite the “low glycemic” branding it lands near 54, essentially the same as table sugar. Agave is the sneakiest: its glycemic index is low, around 15, so it gets a health halo, but that is because it is mostly fructose, and at about 15g of carbs per tablespoon it will blow your daily budget in one drizzle. None of these belong on keto. Check the keto food list when in doubt about any so-called natural sweetener.
Hidden bulking agents
Even a genuinely keto sweetener can betray you through its filler. Bagged sucralose (Splenda) and many “measures like sugar” products are bulked with maltodextrin or dextrose so a cup of the product weighs and pours like a cup of sugar. Maltodextrin has a glycemic index higher than table sugar. The amount per serving is small, but it adds up fast when a recipe calls for a full cup. Scan the ingredient list, not just the front label, and prefer erythritol- or allulose-based blends where the bulk itself is keto.
How much you can eat before digestive upset
Sugar alcohols draw water into the gut and ferment in the colon, which is why too much causes bloating, gas, and loose stools. Tolerance is individual, but general thresholds help.
- Erythritol is the best tolerated of the sugar alcohols because most of it is absorbed before it reaches the colon. Most people handle 20 to 30g a day, or about 0.5g per pound of body weight in a single sitting, before symptoms appear.
- Xylitol ferments more, so the comfortable ceiling is lower, often around 15 to 20g at once. It also bakes and tastes closest to sugar, so it is easy to overdo.
- Maltitol is the worst offender for gut symptoms and the reason “sugar-free” candy has a laxative reputation. Even 10 to 20g can trigger cramping in sensitive people.
- Allulose is technically not a sugar alcohol and is generally the gentlest, though large servings can still cause discomfort.
Whichever you choose, introduce it gradually and split servings across the day rather than eating a whole batch of cookies in one go.
A critical warning: xylitol is toxic to dogs
Xylitol is a perfectly good keto sweetener for humans, with a glycemic index of only 7 to 13 and a near 1:1 sugar swap, but it is extremely toxic to dogs. Even a small amount triggers a rapid insulin release in dogs that can cause life-threatening hypoglycemia and liver failure. If you bake with xylitol or keep it in the pantry, store it well out of reach and never share xylitol-sweetened treats with pets. Many sugar-free gums and peanut butters also contain it, so check labels before giving a dog any human food. If you have dogs in the house, erythritol or monk fruit blends are the safer choice.
Stevia and the artificial sweeteners
Stevia is a zero-carb, zero-glycemic extract from the stevia leaf that is 200 to 350 times sweeter than sugar. It is excellent in coffee, tea, and drinks as a few drops or a pinch, but its signature bitter, licorice-like aftertaste gets stronger the more you use, which limits it in baking. Like monk fruit, it needs a bulking agent to bake with, and it is often blended with erythritol for that reason. See stevia on keto for the full picture.
Sucralose (Splenda) is 600 times sweeter than sugar in its pure form and does not raise blood sugar, but the bagged granulated version is bulked with carbs, and it can develop an off, slightly bitter flavor at high baking temperatures. Aspartame is about 200 times sweeter, has negligible carbs, and does not affect ketosis, but it breaks down under heat, so it is a tabletop sweetener, not a baking one. Tagatose is a lesser-known option that is about 90% as sweet as sugar, browns and caramelizes nicely, and has a low glycemic index of 3, though it carries a small carb count and is harder to find.
Why blends exist
If you have wondered why so many keto sweeteners are blends, it is because no single sweetener does everything. Erythritol is cheap and bulks like sugar but has a cooling effect and recrystallizes. Monk fruit and stevia are intensely sweet and clean-tasting but have no bulk to bake with. Allulose browns and stays soft but costs more and is only 70% as sweet. Blends stack their strengths: a monk fruit and allulose blend gets allulose’s browning and moisture plus monk fruit’s rounded sweetness at a manageable price, while a monk fruit and erythritol blend gets cheap bulk with the harsh notes masked. This is why the top-rated products are almost never a single ingredient. When you shop, match the blend to the job: allulose-based for anything soft or caramelized, erythritol-based for crisp cookies and everyday baking on a budget.
The bottom line
For keto and general sugar reduction alike, start with a monk fruit and allulose blend as your do-everything sweetener, keep straight allulose for syrups and soft bakes, and buy plain erythritol for cheap, high-volume baking. Use stevia or monk fruit drops for coffee. Steer clear of maltitol, watch for maltodextrin in the fine print, and remember that honey, maple, agave, and coconut sugar are sugar no matter how they are marketed. For a broader look at where sugar hides in a keto diet, see how much sugar you can have on keto.
