Castor Oil/IPDI Copolymer
Reviewed by Daisy · Last updated 18 Aug 2026
Also known as: Castor Oil, Acetylated Castor Oil, Hydrogenated Castor Oil, PEG-60 Hydrogenated Castor Oil, PEG-40 Hydrogenated Castor Oil, Ricinus Communis (Castor) Seed Oil, Hydrogenated Castor Oil/Sebacic Acid Copolymer
Synthetic polymer | Comprised of castor oil + isophorone diisocyanate
EWG Safety Score
What Is Castor Oil/IPDI Copolymer?
Castor oil/IPDI copolymer is a synthetic polymer consisting of Ricinus communis (castor) seed oil and the synthetic solvent isophorone diisocyanate.
In cosmetics, castor oil/IPDI copolymer is used as a film-forming agent, oil thickener, and a suspending agent, particularly in gels where it’s known to form thick, stable gels. This copolymer is used in lipsticks to impart solidity, structure, and gloss. In emulsions, it imparts a light, silky feeling at dry-down, aiding product aesthetics. It’s also sometimes used in combination with dilinoleic acid/butanediol copolymer to help with pigment dispersion in formulas.
While the independent Cosmetic Ingredient Review panel has not yet assessed this ingredient for its safety, similar polymers have been ruled safe in their current use in cosmetics.
Castor oil/IPDI copolymer is also part of an ingredient blend known as EstoGel® M along with caprylic/capric triglyceride. When used alone, the use levels range from 1–30%, depending on formulary goals.
Clinical Evidence & References
Published Research
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CoSmile Europe, Website, Accessed March 2025 [https://cosmileeurope.eu/inci/detail/2755/castor-oil-ipdi-copolymer]
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ULProspector, Website, Accessed March 2025 [https://www.ulprospector.com/en/na/PersonalCare/Detail/117630/5291313/EstoGel-M]
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Global Substance Registration System, Website, Accessed March 2025 [https://gsrs.ncats.nih.gov/ginas/app/beta/substances/GSA2TXZ34G]
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