PEG-40 Hydrogenated Castor Oil
Reviewed by Rosie · Last updated 18 Aug 2026
Also known as: Castor Oil
Acts as an emollient, emulsifying agent, and solubility-enhancing ingredient | Imparts a soft feel on skin and minimises moisture loss
Addresses
EWG Safety Score
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What Is PEG-40 Hydrogenated Castor Oil?
PEG-40 hydrogenated castor oil is an emollient and emulsifying agent created from a mixture of synthetic polyethylene glycol (PEG) + natural castor oil. It also helps other ingredients solubilize in a formula which improves both aesthetics and performance. Essentially, it meshes water and oil substances, as well as allows other ingredients to dissolve cohesively for a pleasing result.
You can find PEG-40 hydrogenated castor oil in all kinds of personal care formulas including facial cleansers, serums, toners or hair care products. The weight and size of this ingredient is too large to penetrate beyond skin’s surface, but that’s fine—this type of emollient is needed on the surface to minimize moisture loss and impart a soft feel.
PEG-40 hydrogenated castor oil is considered non-sensitizing and safe for use in cosmetics with identified concentrations ranging from 0.00007% to 22% (according to a 2015 report). Safety assessments have shown that even higher concentrations are non-irritating.
Clinical Evidence & References
Published Research
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CosmeticsInfo.org, Accessed July 2021, ePublication [https://cosmeticsinfo.org/ingredient/peg-40-hydrogenated-castor-oil]
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Toxicological Research, June 2015, pages 105-136 [https://www.deepdyve.com/lp/pubmed-central/safety-evaluation-of-polyethylene-glycol-peg-compounds-for-cosmetic-dV2e45HAp7?articleList=%2Fsearch%3Fquery%3DPEG-40%2Bhydrogenated%2Bcastor%2Boil]
From the Clinic
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Take the skin quizOther forms of PEG-40 Hydrogenated Castor Oil
These appear on ingredients lists under different names but are the same substance. PEG-40 Hydrogenated Castor Oil is the common form.
Related Ingredients
PEG-60 Hydrogenated Castor Oil
Primarily used as a cleansing agent | Helps whisk away oil, dirt and other debris
PEG-100 Hydrogenated Castor Oil
A plant-derived emulsifier that helps oils and water blend seamlessly in formulations
PEG-10 Hydrogenated Castor Oil
A plant-derived emulsifier that helps bind water and oil in formulations
PEG-20 Hydrogenated Castor Oil
A plant-derived emulsifier that helps blend water and oil in skincare formulas
PEG
Versatile ingredient used as a cleansing agent, emollient, and emulsifier | Considered safe for skin when used in cosmetic formulations
PEG-33
Lightweight, skin-friendly polymer | Helps draw and hold moisture within skin
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