What it is
This copolymer is a hydrophobically modified acrylic polymer that thickens the water phase of a formulation while its fatty beheneth-25 chains associate to build structure. It helps suspend pigments and other particles, stabilize emulsions, and give products a smooth, even flow. In sunscreens it can contribute to a uniform layer that helps keep UV filters evenly distributed.
Safety & warnings
As a high-molecular-weight polymer, it remains on the surface of the skin and is generally regarded as well tolerated, with a low likelihood of irritation or sensitization at typical use levels. It is not considered comedogenic.
Origin & sourcing
It is a synthetic polymer made by copolymerizing acrylic acid esters with a beheneth-25 methacrylate monomer.
Questions everyone asks
Why is this polymer used in sunscreens?
It thickens and stabilizes the water phase, helping suspend UV filters and pigments evenly so the product applies in a smooth, consistent layer.
Is it the same as a simple thickener?
It is an associative thickener, meaning it builds viscosity both by swelling in water and through its fatty side chains, which can give a distinctive light texture.