Anhydroxylitol is a chemical compound obtained by synthesis from the dehydration of xylitol (a sugar alcohol with five carbon atoms) under acidic conditions. Highly soluble in water.

The name defines the structure of the molecule:

• Anhydro- comes from the Greek words 'an' meaning 'without' and 'hydro' meaning 'water'. In chemistry, it is used to indicate the removal of a water molecule during the formation of a compound.
• Xylitol is a five-carbohydrate sugar alcohol found in many fruits and vegetables used as a sugar substitute.

The synthesis of anhydroxylytol generally involves the dehydration of xylitol:

• Dehydration of xylitol. Xylitol is heated under acidic conditions to remove a water molecule, forming Anhydroxylitol .

It takes the form of a yellowish liquid.

What it is used for and where

Cosmetics

Used in creams and personal care products as a humectant and moisturising agent that maintains the water content of a cosmetic both in the packaging and on the skin. It is usually combined with Xylitylglucoside. It also has a skin-penetrating effect and allows the other components of the formulation to penetrate the skin more easily.

Humectant. Hygroscopic compound used to minimise water loss in the skin and to prevent it from drying out by facilitating faster and greater absorption of water into the stratum corneum of the epidermis.  The epidermis is the most superficial of the three layers that make up human skin (epidermis, dermis and hypodermis) and is the layer that maintains hydration in all three layers. In turn, the epidermis is composed of five layers: horny, the most superficial, granular, spinous, shiny, and basal. Humectants have the ability to retain the water they attract from the air in the stratum corneum and have the function of moisturising the skin. They are best used before emollients, which are oil-based.

Skin conditioning agent. It is the mainstay of topical skin treatment as it has the function of restoring, increasing or improving skin tolerance to external factors, including melanocyte tolerance. The most important function of the conditioning agent is to prevent skin dehydration, but the subject is rather complex and involves emollients and humectants that can be added in the formulation.

Safety

It is generally considered safe up to a concentration of 1.5% in cosmetic products. 

Anhydroxylitol studies

Typical commercial product characteristics 1,4-anhydro-D-xylitol

• Molecular Formula  C₅H₁₀O₄
• Molecular Weight     134.13
• Exact Mass   134.05800
• CAS  53448-53-6 491-19-0
• UNII    8XWR7NN42F
• EC Number   258-560-9
• DSSTox Substance ID  DTXSID70964160
• IUPAC  (2R,3R,4S)-2-(hydroxymethyl)oxolane-3,4-diol
• InChI=1S/C5H10O4/c6-1-4-5(8)3(7)2-9-4/h3-8H,1-2H2/t3-,4+,5+/m0/s1  
• InChl Key      KZVAAIRBJJYZOW-VPENINKCSA-N
• SMILES   C1C(C(C(O1)CO)O)O
• MDL number  
• PubChem Substance ID    
• ChEBI  
• RXCUI       1307762
• NSC   
• RTECS   
• UN   
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Synonyms:

• 1,4-anhydro-D-xylitol
• 1,4-anhydroxylitol
• 2-(hydroxymethyl)oxolane-3,4-diol