What is it?
An emulsifier and skin-softening ingredient made by joining capric acid, a 10-carbon fatty acid, to diglycerin, which is two glycerin molecules linked together. The “-2” counts glycerin units; it has nothing to do with ethylene oxide. It helps oils mix with water in skin care products and leaves skin feeling soft.
Key information
- Polyglyceryl-2 caprate is made from glycerin and capric acid; it is not ethoxylated and is not a PEG.
- The number in its name counts glycerin units, not ethylene oxide units.
- The CIR Expert Panel concluded in 2016 that polyglyceryl fatty acid esters are safe as used when formulated to be non-irritating.
- Polyglycerol esters of fatty acids are approved food emulsifiers (E 475 in the EU).
More information
Polyglyceryl esters are made in two steps. First, glycerin is heated with an alkaline catalyst so that glycerin molecules join together, releasing water. Diglycerin, the backbone of this ingredient, is two glycerin units joined by an ether link. Second, the polyglycerin is esterified with a fatty acid, here capric acid. Like PEGs, polyglycerins are polyethers, but they are built by linking glycerin molecules, not by adding ethylene oxide, so these are not ethoxylated ingredients. The CIR report notes that routes using epichlorohydrin or glycidol exist but are less economical than the glycerin route, and in 2022 EFSA reported that suppliers of food-grade polyglycerol confirmed they do not use epichlorohydrin.
The Cosmetic Ingredient Review (CIR) Expert Panel assessed 274 polyglyceryl fatty acid esters in 2016, including this one, and concluded they are safe as used when formulated to be non-irritating. It added that proviso because some esters in the group, such as certain isostearates and oleates, irritated rabbit skin. Close relatives of this ingredient, polyglyceryl-3 caprate and polyglyceryl-4 caprate, did not irritate rabbit skin or eyes and did not cause allergic sensitization in guinea pigs. In 2016 polyglyceryl-2 caprate was reported in only six products.
As food emulsifiers (E 475), polyglycerol esters were re-evaluated by EFSA in 2017. It found that very little is absorbed intact and that they are rapidly broken down into polyglycerols and fatty acids in the gut, and it concluded there was no safety concern at reported uses and no need for a numerical acceptable daily intake.
On labels, look for “polyglyceryl-” followed by a number and a fatty acid name. The “poly” refers to glycerin, not to ethylene oxide.
Sources: Cosmetic Ingredient Review: Safety assessment of polyglyceryl fatty acid esters as used in cosmetics (2016); EFSA: Re-evaluation of polyglycerol esters of fatty acids (E 475) as a food additive (2017); EFSA: Follow-up of the re-evaluation of polyglycerol esters of fatty acids (E 475) (2022)
