At a glance
- CAS number
- 9004-99-3
- INCI name
- PEG-100 Stearate
- Function
- emulsifier, solubilizer, surfactant
- Typical use level
- 1%–5%
- Solubility
- water
- Stable pH
- 4–8
CAS number and synonyms are sourced from PubChem. Function, usage levels, pH and compatibility are AI-assisted formulation guidance — verify against your supplier's technical data sheet and applicable regulations before use.
Also known as
Polyethylene Glycol 100 Stearate POE (100) Stearate PEG 4000 Monostearate Polyoxyethylene (100) Stearyl Ether
Compatibility
Works well with:
Glyceryl Stearate Cetyl Alcohol Stearic Acid Niacinamide Glycerin Dimethicone
Use caution with:
Strong acids Strong alkalis High concentrations of electrolytes
PEG-100 Stearate is frequently paired with Glyceryl Stearate to form a robust self-emulsifying system for oil-in-water emulsions. High electrolyte concentrations can cause salting-out and reduce emulsification efficiency. Avoid prolonged exposure to extremes of pH, which can hydrolyze the ester bond over time.
Formulation notes
PEG-100 Stearate is a high-HLB (approximately 18) nonionic emulsifier derived from stearic acid and polyethylene glycol with 100 ethylene oxide units, making it highly hydrophilic and well suited for stabilizing oil-in-water emulsions. It is widely used in lotions, creams, and serums to provide a smooth, non-greasy skin feel. It has a good safety profile at typical use levels, though formulators should be aware that PEG-based ingredients may carry trace levels of 1,4-dioxane if not purified, so sourcing from suppliers using ethoxylation distillation processes is advisable.
Related ingredients
- Cetearyl GlucosideEmulsifier
- Polysorbate 20Emulsifier
- Polysorbate 80Emulsifier
- Behenyl PEG/PPG-20/20 DimethiconeEmulsifier
- Cetyl PhosphateEmulsifier
- LecithinEmulsifier