What it is
Phenylpropyldimethylsiloxysilicate is a branched silicone resin in which a portion of the methyl groups carry phenylpropyl substituents, giving it greater compatibility with phenyl silicones and certain organic emollients than standard trimethylsiloxysilicate. In sunscreens and color cosmetics it deposits a continuous, cohesive film that helps hold pigments, UV filters, and other actives in place on the skin surface and improves wear time. It is typically supplied predispersed in a volatile silicone or other carrier and contributes to a smooth, non-tacky finish.
Safety & warnings
Silicone resins of this type are large, inert film formers that are generally well tolerated, with low irritation and sensitization potential and a low likelihood of penetrating skin. They are considered non-comedogenic in typical use. As with any film-forming silicone, thorough cleansing helps avoid buildup.
Origin & sourcing
Synthetic. It is a silicone (polysiloxane) resin manufactured by polymerizing siloxane units, with phenylpropyl groups introduced to modify solubility and compatibility.
Questions everyone asks
What does phenylpropyldimethylsiloxysilicate do in a sunscreen?
It forms a flexible silicone film that binds pigments and UV filters to the skin, improving the evenness and longevity of the applied layer.
Is it a UV filter?
No. It does not absorb or scatter UV light itself; it is a film-forming resin that helps carry and hold the actual UV filters in place.