What is it?
A waxy ester of ethylene glycol and stearic acid, made up of a mix of the monoester and the diester. It is best known for giving shampoos, soaps, creams and lotions an opaque, milky look, and it also helps emulsify, thicken and stabilize creams and makeup. Its close relative glycol distearate is used mainly in hair care products.
Key information
- The CIR Expert Panel concluded in 1982 that glycol stearate is safe as used, reaffirmed that in 2003 and confirmed it again in a re-review published in 2023.
- In 2022 it was reported in 602 cosmetic products, at up to 5 percent.
- The CIR says ethylene glycol and/or ethylene oxide are used to make it and that trace 1,4-dioxane is possible, but no measurements were available.
- The known danger of ethylene glycol comes from swallowing it; in this ingredient it is bound up in a waxy ester.
More information
Glycol stearate is a mix of mono- and diesters of ethylene glycol with commercial stearic acid, which is itself roughly equal parts stearic and palmitic acid. According to the Cosmetic Ingredient Review (CIR), ethylene glycol and/or ethylene oxide are used to make it, and impurities can include free stearic acid and ethylene glycol. The CIR also noted that ethylene glycol can carry traces of 1,4-dioxane, so traces could appear in glycol stearate, but no measurements were available to the panel.
The CIR Expert Panel concluded in 1982 that glycol stearate is safe as used, reaffirmed that in 2003 and confirmed it again in a re-review published in 2023. Reported use grew to 602 products in 2022, at up to 5 percent. It had low acute toxicity in animals and was at most slightly irritating to rabbit skin; human tests of products with 2 to 5 percent found no irritation or allergy. The original panel noted that longer-term animal studies were lacking. In a 1989 rabbit-ear survey, ethylene glycol monostearate scored 0 of 5 for both pore clogging and irritation.
We rate ethylene glycol Red Light. Its well-known danger is swallowing: the ATSDR says larger amounts, as in antifreeze, can cause serious illness or death, as the body turns it into compounds that harm the kidneys. In glycol stearate the glycol is bound in a large waxy ester used at a few percent, so we would not expect that concern to carry over. The open questions are residual free ethylene glycol and possible manufacturing traces such as 1,4-dioxane.
Reality check: glycol stearate is not ethylene glycol, and its safety record at the levels used is good. Because it can be made with ethylene oxide and residue data are lacking, people who avoid ethoxylated ingredients may choose to avoid it too.
Sources: Cosmetic Ingredient Review: Re-review of glycol stearate and glycol stearate SE, with the 1982 final report and 2003 re-review (2022); International Journal of Toxicology (2023), PubMed record: Glycol stearate and glycol stearate SE; ATSDR: ToxFAQs for ethylene glycol; Journal of the Society of Cosmetic Chemists (1989): Comedogenicity and irritancy of commonly used ingredients in skin care products