What it is
PEG-5 Phytosterol is made by ethoxylating phytosterols, the sterol fraction of plant oils, so the resulting molecule combines a lipid-like sterol portion with a short water-loving PEG chain. This amphiphilic structure lets it act as a nonionic emulsifier and solubilizer, helping oil and water phases blend into stable, smooth emulsions. In sunscreens and creams it also contributes light emollient and conditioning effects that improve spreadability.
Safety & warnings
PEG-5 Phytosterol is generally well tolerated in rinse-off and leave-on products at typical use levels. As with other PEG-based ingredients, trace impurities such as 1,4-dioxane and ethylene oxide can be present from the ethoxylation process, which reputable manufacturers control through purification. It is not a recognized fragrance allergen.
Origin & sourcing
Semi-synthetic: the phytosterol backbone is derived from plant sources such as soybean or other vegetable oils, then chemically reacted with ethylene oxide to add the polyethylene glycol chain.
Questions everyone asks
What does PEG-5 Phytosterol do in a sunscreen?
It works mainly as an emulsifier and solubilizer, helping the oil and water portions of the formula stay blended while adding a light conditioning feel.
Is PEG-5 Phytosterol natural or synthetic?
It is semi-synthetic: a plant-derived phytosterol that has been chemically modified with a polyethylene glycol chain.