What is Allulose?

What is Allulose?

Allulose, also known as D-psicose or D-allulose, is a rare monosaccharide sugar with the chemical formula C₆H₁₂O₆ — the same as glucose and fructose. It is classified as a C-3 epimer of D-fructose, meaning it differs from fructose only in the configuration of the hydroxyl group at the third carbon atom.

Despite being a "sugar" in chemical terms, allulose behaves very differently from conventional sugars in the human body. It provides approximately 0.4 kcal/g (about 1/10 the calories of sucrose) and has a near-zero glycemic index.

This page is the definition-level companion to the full Allulose Guide. The guide page explains benefits, safety, side effects, FDA labeling, baking, and applications in more depth; this page focuses on what allulose is and why it behaves differently from ordinary sugar.

Chemical Classification

Allulose belongs to the rare sugar family — monosaccharides that exist in extremely small quantities in nature. Unlike abundant sugars such as glucose (in starch) or fructose (in fruit), rare sugars like allulose are found only in trace amounts.

As a ketohexose (6-carbon ketose sugar), allulose shares the same molecular weight as glucose (180.16 g/mol) but has distinctly different biological properties due to its unique stereochemistry.

History of Discovery

• 1940s: Allulose was first isolated from wheat bran by researchers studying rare sugars
• 1994: Professor Ken Izumori at Kagawa University (Japan) discovered the enzymatic pathway for converting fructose to allulose, later known as the Izumori Ring
• 2011: The enzyme D-tagatose 3-epimerase (DTEase) enabled industrial-scale bioconversion of fructose to allulose
• 2014: FDA accepted allulose as Generally Recognized as Safe (GRAS) in the United States
• 2019: FDA ruled that allulose does not need to be counted as "added sugar" on Nutrition Facts labels
• 2020s: Major food companies worldwide began incorporating allulose into commercial products

Natural Sources

Allulose occurs naturally in small quantities in several foods:

Source	Approximate Allulose Content
Figs (dried)	~150 mg/100g
Raisins	~100 mg/100g
Maple syrup	~80 mg/100g
Jackfruit	~50 mg/100g
Wheat	~40 mg/100g
Molasses	~30 mg/100g

Due to its extremely low natural abundance, commercial allulose is produced via enzymatic conversion from fructose (typically derived from corn starch).

Commercial Production

Modern allulose production uses the enzymatic epimerization process:

1. Feedstock preparation: Fructose solution derived from corn starch
2. Enzymatic conversion: D-tagatose 3-epimerase (DTEase) or D-psicose 3-epimerase (DPEase) converts fructose → allulose
3. Separation and purification: Chromatographic separation, filtration, crystallization
4. Drying and packaging: Final product as crystalline powder

Baolingbao Biology operates one of the world's largest allulose production lines with an annual capacity exceeding 10,000 metric tons.

What Makes Allulose Different in the Body?

The main difference between allulose and sucrose is not only sweetness. It is metabolism. Human and animal studies indicate that most consumed allulose is absorbed and excreted largely intact, so it contributes very little usable energy compared with ordinary carbohydrates.

For nutrition labeling in the United States, FDA guidance allows manufacturers to use 0.4 kcal/g for allulose when calculating calories on Nutrition and Supplement Facts labels. The same guidance states that FDA intends to exercise enforcement discretion for excluding allulose from Total Sugars and Added Sugars, while allulose still needs to be declared in the ingredient statement and included in Total Carbohydrate.

From a food science perspective, this creates a rare combination:

• It is chemically a sugar.
• It tastes and processes more like sugar than high-intensity sweeteners.
• It contributes far fewer calories than sucrose.
• It can support reduced-sugar label strategies in markets where the regulatory status permits.

Research Evidence: Blood Sugar, GLP-1, and Metabolism

The Tencent-hosted paper project used for this site tracks allulose literature from PubMed and PMC. The current allulose literature database includes 119 curated records, while the broader allulose and rare-sugar index contains about 226 related papers.

Several themes are especially relevant:

• Postprandial glucose: controlled studies and systematic reviews suggest that small doses of allulose may modestly attenuate post-meal glucose and insulin responses when consumed with carbohydrate.
• GLP-1 signaling: preclinical research reports that D-allulose can stimulate GLP-1 release and activate vagal afferent GLP-1 receptor signaling. This is mechanistically interesting, but it should not be described as equivalent to GLP-1 drug therapy.
• Digestive tolerance: allulose is generally well tolerated at typical serving sizes, but high intakes can cause gastrointestinal symptoms in sensitive individuals.
• Safety and toxicology: available safety studies support food-use safety at evaluated levels, while microbiome and long-term intake questions should continue to be monitored.

These findings are useful for explaining allulose as a food ingredient. They should not be used to claim that allulose treats, prevents, or cures diabetes, obesity, or other diseases.

Benefits and Limitations

The clearest benefit of allulose is sugar reduction with better sensory performance. It can replace part of sugar while keeping bulk, body, and a cleaner sweet profile than many high-intensity sweeteners alone.

Allulose also has limitations:

• It is less sweet than sucrose, so blends may be needed.
• It is usually more expensive than commodity sugar and some sugar alcohols.
• Digestive tolerance depends on serving size and total formulation.
• Regulatory treatment varies by market.
• It should be positioned as a food ingredient, not as a medical intervention.

Comparison with Other Sweeteners

Property	Allulose	Sucrose	Erythritol	Stevia
Calories (kcal/g)	0.4	4.0	0.2	0
Sweetness (% of sucrose)	70%	100%	60-70%	200-300x
Glycemic Index	~0	65	0	0
Maillard Reaction	Yes	Yes	No	No
Mouthfeel	Full body	Full body	Cooling effect	Thin
Digestive Tolerance	High	High	Moderate	High
FDA Added Sugar Label	Not counted	Counted	Not counted	Not counted

Allulose is unique among low-calorie sweeteners in that it participates in Maillard browning reactions — enabling proper browning in baked goods, something that erythritol, stevia, and monk fruit cannot achieve.

Where Allulose Is Used in Real Products

GNPD-derived application data reviewed for this project shows allulose appearing across a wide range of commercial foods and beverages. The published application library on this site currently includes 52 product case analyses, with the largest groups in snack bars, confectionery, beverages, bakery, frozen desserts, and dairy.

Common use cases include:

• Snack bars: bulk sweetness, texture, and low-sugar positioning.
• Confectionery: sugar-like sweetness and bulk without strong cooling.
• Beverages: clean sweetness, solubility, and acid stability.
• Bakery: Maillard browning, humectancy, and softer texture.
• Frozen desserts: sweetness, body, and freezing-point control.
• Dairy: sweetness and mouthfeel in yogurts, flavored milk, and protein drinks.

For a category-by-category view, see Allulose Applications and the Application Examples library.

Sources

• Izumori K. Bioproduction strategies for rare hexose sugars. Naturwissenschaften. 2002;89(3):120-124. (Discovery of the Izumori Ring — enzymatic pathway for rare sugar production)
• FDA GRAS Notice No. 498 (2014): Generally Recognized as Safe determination for allulose
• FDA Guidance for Industry (2019): The Declaration of Allulose and Calories from Allulose on Nutrition and Supplement Facts Labels
• Iwasaki Y, et al. GLP-1 release and vagal afferent activation mediate the beneficial metabolic and chronotherapeutic effects of D-allulose. Nature Communications. 2018.
• Braunstein CR, et al. Effect of fructose and its epimers on postprandial carbohydrate metabolism: a systematic review and meta-analysis. Clinical Nutrition. 2020.
• Noronha JC, et al. Rare sugars and their health effects in humans: a systematic review and narrative synthesis. Nutrition Reviews. 2021.
• O'Donnell K, Kearsley M, eds. Sweeteners and Sugar Alternatives in Food Technology. 2nd ed. Wiley-Blackwell; 2012. (Natural occurrence data)