Cetearyl Isononanoate

AKA: CETOSTEARYL ISONONANOATE (EP IMPURITY), CETOSTEARYL ISONONANOATE [EP IMPURITY], CETOSTEARYL ISONONANOATE (EP MONOGRAPH), CETOSTEARYL ISONONANOATE [EP MONOGRAPH], SABODERM CSN, TEGOSOFT CI, CETIOL SN, CETOSTEARYL ISONONANOATE
Synthetic
Emollient
Emulsifier
Synthetic
Clean
OriginDerived from cetearyl alcohol and isononanoic acid, both petroleum-derived synthetic compounds. Synthesized through esterification, combining cetearyl alcohol with isononanoic acid under catalytic conditions.
The CIR Expert Panel concluded that the alkyl esters, listed subsequently, are safe in the present practices of use and concentration described in this safety assessment when formulated to be non-irritating.
Formula
C25H50O2
Mol. Weight
382.70
CAS #
111937-03-2
Form
Liquid
Skin Types
●all-skin-types
Best For
Dryness
Pregnancy & Breastfeeding Safe
Yes
Functions
Emollient
Fills in the tiny cracks between skin cells to make everything feel smooth and soft. The "silky finish" ingredient.
Emulsifying
Forces oil and water to stay mixed instead of separating into layers. The unsung hero holding your lotion together.
Softens & Smooths
Conditions Hair
Conditions Skin
Smooths and softens skin
Softens and detangles hair
The paper trail
🔬Peer-reviewed1 paper →
⚖️Regulatory0 listings
🛡️Safety-assessed3 reviews →
Counts, not a verdict. A listing isn't a study. The trail, you decide.
EWG
1
CIR
Insufficient
Pregnancy
Yes
CIR Safety Findings
Not Comedogenic
Animal test found no comedogenicity in the CIR safety assessment (CIR 558 and 623)
Not an Eye Irritant
1 study / 1 not irritating (CIR 558)
Not a Sensitizer
3 studies / 3 not sensitizing / plus 1 case report (CIR 558)
Mixed Skin Irritation Results
5 studies / 1 irritating / 1 mixed / 3 not irritating / reactions slight (CIR 558 and 623)
Concentration Guide
Leave-on0.2–40%
Rinse-off1–4%
0%50%100%
CIR reported use · 2012 survey
Regulatory Agencies
Verified Jun 2026
Data: PubChem · CosIng · EWG · CIR
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