What it is
This is a high-molecular-weight copolymer of partially neutralized acrylic acid and a maleic-type comonomer, supplied in its sodium salt form. In a sunscreen it builds viscosity and helps suspend or stabilize the emulsion so the product stays uniform and spreads evenly. As a film former it can also contribute to a smooth feel and help the formula deposit a more even layer on skin.
Safety & warnings
Acrylate copolymers of this type are large molecules that remain on the skin surface and are generally well tolerated, with a low likelihood of irritation or sensitization at typical use levels. They are not associated with comedogenicity or known fragrance allergens.
Origin & sourcing
Synthetic, produced by polymerizing petrochemically derived acrylic acid and a co-monomer, then neutralizing with sodium.
Questions everyone asks
What does this ingredient do in a sunscreen?
It acts as a thickener and stabilizer, helping the formula reach the right consistency and keeping the emulsion uniform so it applies evenly.
Is it a natural ingredient?
No. It is a synthetic acrylate copolymer made by polymerization, supplied as the sodium salt.