Diglycerin is a highly pure polyol with four hydroxyl groups produced through reaction, distillation, glycerine refining and a dimer of Glycerin.

It appears as a colourless liquid.

What it is used for and where

Cosmetics

Diglycerin is widely used as a moisturizer and humectant in cosmetics and as a raw material for fatty acid esters and other substances.

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.

It is always the desire of a formulator of personal care products to identify materials that will provide cost-advantageous sensory qualities to those products. Often, materials are identified for certain uses in products but can be used in other applications to create unique qualities.Humectants are hygroscopic materials that act as moisturizers by binding water. They are important ingredients in cosmetic formulations, as moisturizers and also to prevent formulations such as creams from drying out. The ability of humectants to moisturize the skin is a function of their propensity for water absorption as well as water retention.  Humectants play an important role in toothpaste and deodorant sticks. It is in these two areas that we shall discuss the incorporation of a unique material: diglycerol (INCI: diglycerin) (1).

• Linear Formula  O(CH₂CHOHCH₂OH)₂  
• Molecular Formula  C₆H₁₄O₅
• Molecular Weight 166.173 g/mol
• CAS    59113-36-9     25618-55-7
• EC number   261-605-5

Synonyms : 

• Diglycerol
• Glyceryl ether
• 3-(2,3-dihydroxypropoxy)propane-1,2-diol
• Diglycerine
• 1,2-Propanediol, 3,3'-oxybis-
• EINECS 211-013-8
• Tetrahydroxydipropyl Ether
• 4-Oxaheptane-1,6,7-tetrol
• 3-glyceryloxypropane-1,2-diol

References____________________________________________________________________

(1) Roger E. Stier and Jacqueline Lucia  Diglycerol: a humectant with unique sensory qualities  Noville Inc.2009