Common Name(s): Polyethylene glycol 4000 stearate,peg-100 monostearate
CAS Number: 9004-99-3
DESCRIPTION
What It Does: Provides high-hlb o/w emulsification as a co-emulsifier partner in standard cream formulations.
Why It's Used: Standard high-hlb co-emulsifier for gms/fatty alcohol/peg-100 stearate classic cream formulation systems.
How It Works: High peg chain length provides hlb ~18 for strong water-phase affinity. combined with low-hlb gms (hlb ~3) at appropriate ratio achieves target hlb for stable o/w emulsification. high hydrophilicity also provides solubilization of oil-soluble ingredients.
Typically Found In: Classic creams and lotions
TECHNICAL DETAILS
Primary Category: Functional ingredient โ peg ester emulsifier
Secondary Functions: Skin conditioning
Application Areas:
Facial Skincare
Body Care
Hair Care
Beard Care
Color Cosmetics (Makeup)
Dietary/Oral Supplements
Typical Concentration Range: 0.5%โ5%
SOURCING & ETHICS
Vegan Status: Conditional - feedstock declaration required
Halal Status: Unverified - feedstock declaration required (plant, animal and petrochemical routes all exist)
Source Notes: Commercially produced for cosmetic use. verify vegan/halal status with supplier. [audit 2026-07-29 rev2: origin-dependent: the same inci exists in plant, animal and petrochemical versions and the name does not discriminate. determination requires shariah-panel sign-off.]
SKIN COMPATIBILITY
Irritancy Rating: 1/5 โ very low
Comedogenicity Rating: 0/5 โ non-comedogenic
Sensitivity Concerns: Well-tolerated by most skin types.
Safe for Sensitive Skin: Yes
SAFETY & COMPATIBILITY
Safety Profile: Eu cosmetics regulation: peg compounds may contain 1,4-dioxane impurity from peg manufacture. quality-grade peg-100 stearate should have <10ppm 1,4-dioxane.
Works Well With: Standard skincare actives
Avoid Combining With: No known significant incompatibilities
SCIENTIFIC NOTE
Peg-100 stearate's hlb value of ~18 paired with gms's hlb of ~3 provides the classic 'required hlb matching' for emulsification of common cosmetic oils. when combined at approximately a 1:3 gms:peg-100 ratio, the blended hlb (~7) matches the required hlb of most mineral and vegetable oils, providing the theoretical basis for one of the most widely used cream formulation systems.
Last Verified: 2026-03-12
Primary Sources: Cosing database,cir safety assessment