Pe
PEG-40 Stearate
PEG-40 Stearate
A PEG emulsifier that keeps oil and water evenly blended.
What it does
It’s made by attaching about 40 links of PEG to stearic acid, a fatty acid. That long PEG part draws it toward water, so it suits light lotions and helps cleansers rinse off.
The evidence, graded
expert consensusUS safety reviewers’ 1983 report describes PEG stearates as stearic acid joined to polyethylene glycol, used mainly to help oil and water blend (as surfactants) and to soften skin, at up to 25%. Because they dissolve in both water and oil, the report says, they are very good at keeping the two mixed. The 2025 second look says their main jobs are as surfactants and skin softeners.Cosmetic 1983 · Journal of the American College of Toxicology 2(7):17-34 ↗
expert consensusIn studies on people in US safety reviewers’ 1983 report, PEG stearates did not irritate or cause allergy at 25% or more, and the reviewers judged them safe at the amounts and in the ways cosmetics use them. Their 2025 second look reached the same conclusion, and their index lists PEG-40 and PEG-100 stearate under it.Cosmetic 1983 · Journal of the American College of Toxicology 2(7):17-34 ↗
expert consensusUS safety reviewers’ 1983 report says trace 1,4-dioxane, a by-product of the process used to make PEGs (ethoxylation), may be present, and that industry uses extra purification steps to remove it. EU Regulation 1223/2009 bans dioxane (Annex II, entry 343). Article 17 allows a small unintended trace of a banned substance only if it is technically unavoidable. The product must still be safe (Article 3).Cosmetic 1983 · Journal of the American College of Toxicology 2(7):17-34 ↗
Graded per the methodology: strong · moderate · emerging · expert consensus. A weak source on a strong claim gets the weaker label.
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