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CAS number 23140-52-5 N
PubChem 90008
ChemSpider 81254 YesY
MeSH psicose
ChEBI CHEBI:27605 YesY
Jmol-3D images Image 1
Molecular formula C6H12O6
Molar mass 180.16 g mol−1
Melting point 58 °C (136 °F; 331 K) [1]
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 N (verify) (what is: YesY/N?)
Infobox references

D-Psicose (D-allulose, D-ribo-2-hexulose, C6H12O6) is an ultralow-energy monosaccharide sugar. It is a C-3 epimer of D-fructose, and is present in small quantities in agricultural products and commercially prepared carbohydrate complexes. It is known as a rare sugar because it is rarely found in nature, and even when found, only in small amounts. D-Psicose yields only 0.3% the metabolic energy of the equivalent amount of sucrose.[2] Its name derives from the antibiotic psicofuranine, from which it can be isolated.

Research is being conducted into how it can be used in diets to aid in combating hyperglycemia, hyperlipidemia, and obesity. The first mass production method for D-psicose was established when Ken Izumori at Kagawa University in Japan discovered the key enzyme, D-tagatose 3-epimerase, to convert fructose to D-psicose in 1994.[3][4] This method of D-psicose production has a high yield but suffers from a very high production cost, in the hands of the Kagawa research group. In 2012, Food and Drug Administration (FDA) issued a letter of no questions for the notification of D-psicose being generally recognized as safe (GRAS), paving the way for use in food in the US. [5][6]


  1. ^ David R. Lide, G.W.A. Milne, ed. (December 30, 1993). CRC Handbook of Data on Organic Compounds (3rd ed.). CRC Press. p. 4596. 
  2. ^ Matsuo T, Suzuki H, Hashiguchi M, Izumori K (2002). "D-psicose is a rare sugar that provides no energy to growing rats". J Nutr Sci Vitaminol(Tokyo). 48 (1): 77–80. PMID 12026195. 
  3. ^ Itoh H, Okaya H, Khan AR, Tajima S, Hayakawa S, Izumori K (1994). "Purification and characterization of D-tagatose 3-epimerase from Pseudomonas sp. ST-24". Biosci Biotechnol Biochem. 58: 2168–2171. doi:10.1271/bbb.58.2168. 
  4. ^ Itoh H, Sato T, Izumori K (1995). "Preparation of d-psicose from d-fructose by immobilized d-tagatose 3-epimerase." J Fermentation and Bioengineering 80(1): 101–103.
  5. ^ GRAS Notice Inventory
  6. ^ "GRAS exemption claim for D-psicose as an ingredient in foods.".