What Is Allulose? The Sugar That Doesn't Count as Sugar
Quick answer: What is allulose? A rare sugar found naturally in figs, raisins, and maple syrup, now produced at scale from corn, that the body absorbs but barely uses for energy. The U.S. Food and Drug Administration assigns it 0.4 calories per gram against 4.0 for table sugar and allows manufacturers to leave it out of Total Sugars and Added Sugars on the label. The limit is digestive rather than metabolic: research puts the comfortable ceiling near 0.4 grams per kilogram of body weight in one sitting.
Read the back of a new "zero sugar" syrup or frozen dessert and the arithmetic sometimes refuses to add up: 15 grams of total carbohydrate, 0 grams of total sugars, and an ingredient list whose second line is unmistakably a sugar. Nothing is being hidden. A small group of sugars are metabolized differently enough that regulators count them differently, and one of them has moved from lab curiosity to mainstream shelf ingredient faster than the rest. Here is what it is, why the label counts it the way it does, what the research supports, and the dose at which most people stop enjoying it.
What is allulose, and where does it come from?
Allulose, also written as D-allulose or D-psicose, is a monosaccharide with the same chemical formula as fructose and a different three-dimensional arrangement at one carbon. That single structural difference is the whole story: the enzymes that break fructose down for energy do not recognize it efficiently. It occurs naturally in figs, raisins, jackfruit, wheat, and maple syrup, but only in trace amounts.
Commercial allulose is made enzymatically, converting fructose from corn into its rare-sugar cousin. It is about 70 percent as sweet as table sugar, dissolves and browns much the way sugar does, and contributes bulk to a recipe. That last property is why formulators reach for it where stevia and monk fruit fall short: those sweeteners are hundreds of times sweeter than sugar by weight, so a recipe uses a pinch and loses all the structure sugar was providing.
Why allulose doesn't count as sugar on the label
In October 2020 the U.S. Food and Drug Administration finalized guidance stating it does not intend to object when manufacturers exclude allulose from the Total Sugars and Added Sugars lines, and when they calculate it at 0.4 calories per gram instead of the 4.0 used for traditional sugars. Allulose must still be declared inside Total Carbohydrate. That is why the carbohydrate number on a package can be large while the sugar number reads zero.
The reasoning is metabolic. Allulose is absorbed in the small intestine, but most of what is absorbed is excreted unchanged rather than burned for energy, which is why it produces only negligible increases in blood glucose and insulin. Worth knowing: this is enforcement discretion rather than a finished rule, issued pending a broader rulemaking on sugars that are metabolized differently. A front-of-pack "0 grams of sugar" claim on an allulose-sweetened product is accurate under current labeling policy while the product does, chemically speaking, contain a sugar.
What the blood sugar research actually shows
Consumed on its own, allulose does not appear to move blood glucose meaningfully. A 15-gram dose produced no glucose or insulin response in controlled testing, consistent across acute studies and a 48-week trial. More interesting is what happens in combination: a 2023 randomized controlled trial found that allulose added alongside sucrose flattened the post-meal glucose curve compared with sucrose alone.
These are short trials at modest doses in mostly healthy adults. They support the claim that allulose is a sweetener with a negligible glycemic footprint, and nothing beyond that.
The dose where allulose stops being comfortable
Every low-calorie sugar shares one constraint: what the small intestine does not absorb, the colon ferments. A 2018 dose-escalation study in Nutrients raised intake in increments of 0.1 grams per kilogram of body weight and recorded no severe gastrointestinal symptoms until 0.4 grams per kilogram in a single sitting, with severe symptoms appearing at 0.5. Its authors proposed a maximum single dose of 0.4 grams per kilogram, roughly 27 grams for a 150-pound adult, and a maximum daily intake of 0.9.
A 30-day randomized, double-blind trial published in Food Science & Nutrition in 2026 tested 24 and 36 grams per day in 50 healthy adults. Symptoms were reported by 48 percent of participants, but they were mild, transient, and clustered in the first three days, and the authors proposed a provisional safe intake of 0.4 grams per kilogram per day. Tolerance builds, in other words, but the ceiling is real, and it sits higher than the ceiling for most sugar alcohols.
How allulose compares to other sweeteners
Six sweeteners on the variables that decide a formulation, at nutrition-labeling calorie values.
| Sweetener | Calories per gram | Sweetness vs. table sugar | Effect on blood glucose | Counted in Total Sugars? |
|---|---|---|---|---|
| Allulose | 0.4 | ~70% | Negligible | No, by enforcement discretion |
| Erythritol | 0.2 | ~70% | Negligible | No, declared as a sugar alcohol |
| Xylitol | 2.4 | ~100% | Small rise | No, declared as a sugar alcohol |
| Maltitol | 2.1 | ~80% | Moderate rise | No, declared as a sugar alcohol |
| Coconut sugar | 3.8 | ~100% | Raises glucose | Yes |
| Cane sugar | 4.0 | 100% | Raises glucose | Yes |
Read the last two columns together and the trade-off is clear: the sweeteners that disappear from the sugar line are the ones carrying a digestive ceiling, and the ones that behave like sugar in the mouth and in the gut are the ones that get counted. Marmels sits deliberately on the counted side, using organic coconut sugar for 12 grams of sugar in a 60-gram bar rather than engineering that number to zero, because 12 grams of protein and 62% single-origin organic cacao are doing the work a lower sugar figure would otherwise be asked to justify.
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Frequently Asked Questions
Is allulose safe?
In the United States, allulose is generally recognized as safe, and it is approved in Japan, South Korea, Mexico, and Singapore. It is not authorized in the European Union or Canada. A June 2025 European Food Safety Authority opinion concluded that safety could not be established on the data submitted, because the applicant did not supply the information requested rather than because of an adverse finding.
Does allulose raise blood sugar?
Not meaningfully, according to the available trials. A 15-gram dose produced no measurable glucose or insulin response, and results have held in studies running up to 48 weeks. These are short studies at modest doses and should be read as sweetener research, not as guidance for any condition.
What are the side effects of allulose?
The reported effects are digestive: bloating, abdominal distention, gas, and diarrhea at higher intakes. A 2018 dose-escalation study found severe symptoms beginning at 0.5 grams per kilogram of body weight in one sitting. A 2026 trial at 24 to 36 grams per day found symptoms in 48 percent of participants, mild and mostly confined to the first three days.
Is allulose a sugar alcohol?
No. Sugar alcohols such as erythritol, xylitol, and maltitol are hydrogenated carbohydrates with their own line on the Nutrition Facts label. Allulose is a true monosaccharide, structurally a near-twin of fructose, and is declared inside Total Carbohydrate with no dedicated line. The practical similarity is that both are poorly metabolized, which is why both carry a digestive tolerance limit.
Is allulose better than erythritol?
They are close on sweetness and calories, and allulose is generally better tolerated at a given dose. Allulose also browns and caramelizes, which erythritol does not, and it avoids the cooling mouthfeel erythritol leaves behind. Erythritol has the longer use history. Neither is a whole-food ingredient, and both are chosen to engineer a nutrition panel.
Why does a product say zero sugar if it contains allulose?
Because U.S. labeling policy currently permits it. The Food and Drug Administration allows allulose to be excluded from Total Sugars and Added Sugars, so a product sweetened entirely with allulose can declare zero grams of sugar while still containing a sugar by chemistry. The allulose is accounted for in Total Carbohydrate, which is where the numbers reconcile.
Allulose is real food science rather than a gimmick, and the reason to understand it is that the sugar line on a label is no longer a complete description of what a product is sweetened with. For why we went the other direction, have a look at the science behind Marmels.
