What it is
Acrylic acid is the simplest unsaturated carboxylic acid and the chemical precursor to the large family of acrylate polymers, carbomers, and crosspolymers that are widely used as thickeners and film formers in skincare and sunscreens. In a finished product it is not used as the free monomer; instead it is polymerized and neutralized to form the gel-forming and stabilizing networks that give lotions and creams their texture. Its presence on an ingredient list typically reflects the polymer family derived from it rather than the reactive monomer itself.
Safety & warnings
In cosmetics, acrylic acid is encountered as polymerized acrylate derivatives rather than as the free monomer, and these polymers are generally well tolerated and non-sensitizing on intact skin. Residual free monomer is controlled to low levels during manufacture. It is not a recognized fragrance allergen and is not a comedogenic oil.
Origin & sourcing
Synthetic. Acrylic acid is produced industrially, most commonly by the catalytic oxidation of propylene, and is a high-volume petrochemical building block.
Questions everyone asks
Is acrylic acid the same as the thickeners on my sunscreen label?
Not exactly. Acrylic acid is the monomer; the thickeners are polymers made from it, such as carbomers and acrylate crosspolymers, which behave very differently from the reactive monomer.
Does acrylic acid have any skincare benefit on its own?
It is used as a formulation building block rather than an active. Its value comes from the gel-forming and texture-stabilizing polymers it produces.