PEG-4 Diisostearate
AKA “Polyethylene glycol 4 diisostearate
Synthetic
Ingredient Facts
Peg-4 diisostearate
AKA: Polyethylene glycol 4 diisostearate
Synthetic · Emollient · EWG: 4
Plant-Derived Synthetic
Emollient
Cleanser
Emulsifier
Skin Conditioner
Synthetic
Clean
Poly(oxy-1,2-ethanediyl), .alpha.-(1-oxoisooctadecyl)-.omega.-[(1-oxoisooctadecyl)oxy]- (4 mol EO average molar ratio) Science: Origin: Botanic/Natural | Process: Ethoxylation | Functions: Surfactant - Emulsifying Safety Ratings: CIR: Safe as used
Form
Liquid
See origin →
Functions
Emulsifying
Forces oil and water to stay mixed instead of separating into layers. The unsung hero holding your lotion together.
Emollient
Fills in the tiny cracks between skin cells to make everything feel smooth and soft. The "silky finish" ingredient.
Skin Conditioning
A catch-all term for ingredients that improve how skin looks and feels — softer, smoother, more supple. The workhorse behind most moisturizers.
Emulsifier
Locks In Moisture
Wound Healing
Antioxidant Protection
Mixes Oil & Water
Traditional Use
Modern synthetic ester combining isostearic acid with polyethylene glycol, developed as an emollient and emulsifier for stable, luxurious cosmetic textures.
Skin Types
all-skin-types
Best For
General
Melanin-Rich Skin
Suitable
Pregnancy & Breastfeeding Safe
Yes
EWG
4
CIR
Safe w/Qualifications
Pregnancy
Yes
CIR Safety Findings
Not a Sensitizer
medical-approval
all-shades-safe
Regulatory Status
USApermitted
EUrestricted
JAPANrestricted
CANADArestricted
Verified Feb 2026
Data: CosIng · EWG · CIR