PEG-150/Stearyl Alcohol/SMDI Copolymer

INCI: PEG-150/Stearyl Alcohol/SMDI Copolymer | Function: Thickener, Film Former | Type: Polymer

What Is PEG-150/Stearyl Alcohol/SMDI Copolymer?

PEG-150/Stearyl Alcohol/SMDI Copolymer is a high-molecular-weight synthetic polymer composed of PEG-150, stearyl alcohol, and saturated methylene diphenyl diisocyanate (SMDI). It functions as a thickener, film former, and emulsion stabilizer in cosmetic formulations. It builds viscosity without the tackiness of traditional carbomer thickeners.

Key Skin Benefits

+ Viscosity building — thickens aqueous and emulsion systems
+ Film forming — creates a light, flexible film on skin/hair
+ Emulsion stabilization — prevents phase separation

Pros

+ Clear gel formation — ideal for transparent formulations
+ Non-tacky feel at effective concentrations
+ Compatible with high electrolyte systems
+ Temperature-stable viscosity profile

Cons

− Synthetic — petrochemical and isocyanate-derived
− Higher cost than commodity thickeners (carbomer, xanthan)
− SMDI component raises manufacturing complexity concerns

Specifications

Property	Value
Usage Areas	Face, Body, Hair
Product Type	Leave-On, Rinse-Off
Source	Synthetic
Natural Level	Synthetic

Safety Ratings

Metric	Rating
Skin Sensitivity	2/5
Comedogenic Rating	1/5
EWG Score	3/10

Regional Regulatory Limits

Region	Leave-on %	Rinse-off %	Status
EU (CosIng)	No limit	No limit	Allowed
US (CIR/FDA)	No limit	No limit	Allowed
Japan (MHLW)	No limit	No limit	Allowed
ASEAN	No limit	No limit	Allowed
China (NMPA)	No limit	No limit	Allowed

Typical Usage % by Product Type

Product Type	Typical %
Facial serums	0.5 - 2%
Gel moisturizers	0.5 - 1.5%
Hair styling gels	1 - 3%

References

CIR (2010) — Safety Assessment of PEGs. https://www.cir-safety.org/
CosIng (2025) — European Commission Cosmetic Ingredient Database. https://ec.europa.eu/growth/tools-databases/cosing/

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