Researched by Helena DeMaria-Williams
Formula IngredientEmulsifierPEG-100 Stearate
INCI: PEG-100 Stearate
PEG-100 Stearate is a polyethylene glycol ester of stearic acid, formed by reacting stearic acid (a fatty acid from plant or animal fats) with 100 moles of ethylene oxide. It functions as a water-loving (hydrophilic) emulsifier and surfactant that stabilises the oil-water interface in creams, lotions, and serums. It is most commonly used alongside glyceryl stearate, which is oil-loving, to create a highly stable emulsifier pair that performs across a wide pH range and tolerates salts and acidic actives.
Category
Emulsifier
Irritation Risk
Low
Skin Types
all skin types, sensitive, acne-prone, oily, dry, combination
What does this do in a formula?
emulsification, product stabilisation, improved texture and spreadability, mild cleansing
Is PEG-100 Stearate safe? Key considerations
Can PEG-100 Stearate cause irritation?
Low RiskINCIDecoder assigns an irritancy rating of 0. PEG-100 Stearate is not listed under EU CosIng Annex II (banned substances) or Annex III (restricted substances). As with all PEG-derived ingredients, there is a theoretical concern about trace 1,4-dioxane contamination from the ethoxylation manufacturing process; however, reputable manufacturers purge this byproduct and it is not considered a risk at typical cosmetic use levels under EWG or EU regulatory frameworks. No significant irritation is expected at any standard cosmetic concentration.
Does PEG-100 Stearate increase sun sensitivity?
No RiskPEG-100 Stearate is an emulsifier with no photosensitising properties. It does not increase UV sensitivity and no sun protection precautions are required based on its presence in a formulation.
Is PEG-100 Stearate safe during pregnancy?
SafePEG-100 Stearate is a high-molecular-weight topical emulsifier with negligible dermal absorption. No reproductive or developmental toxicity concerns are noted in available cosmetic safety databases. The trace 1,4-dioxane contamination concern that applies to PEG ingredients generally is considered managed by good manufacturing practice. It is widely used in mainstream skincare products with no pregnancy-specific restrictions. MANUAL REVIEW: No specific MotherToBaby entry was found at time of research.
How does PEG-100 Stearate work?
PEG-100 Stearate is a polyethylene glycol ester of stearic acid, formed by reacting stearic acid (a fatty acid from plant or animal fats) with 100 moles of ethylene oxide. It functions as a water-loving (hydrophilic) emulsifier and surfactant that stabilises the oil-water interface in creams, lotions, and serums. It is most commonly used alongside glyceryl stearate, which is oil-loving, to create a highly stable emulsifier pair that performs across a wide pH range and tolerates salts and acidic actives.
Individuals with MANUAL REVIEW: Individuals with specific PEG allergies (rare) should patch test. Those avoiding ethoxylated ingredients for personal or clean-beauty reasons may prefer PEG-free formulations. should review the considerations above before use.
Which products contain PEG-100 Stearate?
Shop products that contain PEG-100 Stearate
