What is it?
A self-emulsifying grade of glyceryl stearate, the ester of glycerin and stearic acid. “SE” means it also contains some sodium and/or potassium stearate, a soap that lets it bring oil and water together without help from other emulsifiers. It is widely used in creams, lotions, makeup and hair products, where it thickens, stabilizes and softens the feel of the formula.
Key information
- The CIR Expert Panel has concluded that glyceryl stearate SE is safe in the present practices of use and concentration.
- In 2015 it was reported in 1,420 cosmetic products, at up to 10 percent.
- It is not an ethoxylated ingredient; the SE grade gets its extra emulsifying power from added sodium or potassium stearate.
- Closely related mono- and diglycerides are food emulsifiers (E 471), which EFSA found to be of no safety concern in 2017.
More information
Monoglycerides such as glyceryl stearate are made by reacting glycerin with a fatty acid, or by reacting fats and oils with glycerin, which gives a mix of mono-, di- and triglycerides. The self-emulsifying grade adds some sodium and/or potassium stearate. No ethylene oxide is used, so it is not one of the PEG or ethoxylated emulsifiers.
The Cosmetic Ingredient Review (CIR) Expert Panel concluded in 1982 that glyceryl stearate and glyceryl stearate SE are safe for topical application. In an amended review of the monoglyceryl monoesters, published in 2020, it concluded they are safe in the present practices of use and concentration. Glyceryl stearate SE was then reported in 1,420 products at up to 10 percent. In rabbits, concentrations up to 100 percent were at most mildly irritating, and 0.1 percent did not cause allergic sensitization in guinea pigs. The panel noted that monoglycerides can help other ingredients pass into the skin.
Similar esters are used in food. In its 2017 re-evaluation of mono- and diglycerides of fatty acids (E 471), the European Food Safety Authority (EFSA) expected them to be broken down in the gut into glycerol and fatty acids, saw no need for a numerical acceptable daily intake and found no safety concern at reported uses. It recommended EU limits for processing contaminants such as glycidyl esters and 3-MCPD.
Glyceryl stearate SE appears on some pore-clogging lists. In a 1989 survey that applied ingredients to the sensitive inner ear of rabbits, it scored 3 of 5 for comedogenicity, against 1 for the non-self-emulsifying grade; the author linked the difference to the added soap. He also called the model extremely sensitive, noting that not everything that irritates it irritates human skin. If you are acne-prone, how a finished product behaves on your skin is the better guide.
Sources: Cosmetic Ingredient Review: Safety assessment of monoglyceryl monoesters as used in cosmetics (draft final amended report, 2015); Cosmetic Ingredient Review: Quick reference table of safety conclusions (September 2022); EFSA Journal (2017): Re-evaluation of mono- and di-glycerides of fatty acids (E 471) as food additives; Journal of the Society of Cosmetic Chemists (1989): Comedogenicity and irritancy of commonly used ingredients in skin care products
