What it is
Ammonium Acryloyldimethyltaurate/VP Copolymer is a copolymer of ammonium acryloyldimethyltaurate and vinylpyrrolidone (VP) monomers that controls viscosity and stabilizes emulsions. In water, the polymer chains swell and entangle to build a clear gel network, which lets formulators create light, gel-like textures that are not tacky or sticky and can also texturize and thicken oil-in-water emulsions. It is supplied pre-neutralized, so it can be cold-processed and works across a broad pH range, and it tolerates high alcohol content better than many other thickeners. Because it is an ammonium salt it is sensitive to electrolytes, and conditions above roughly pH 9 can release ammonia.
Safety & warnings
It is a high-molecular-weight polymer used at low levels (typically around 0.5 to 1.2 percent), and on intact skin it is generally regarded as well tolerated with no specific irritation or allergen warnings noted by ingredient references. People with reactive skin rarely have issues attributable to the polymer itself rather than other components of a formula.
Origin & sourcing
It is a fully synthetic, petrochemically derived polymer made by copolymerizing two monomers, ammonium acryloyldimethyltaurate and vinylpyrrolidone (VP). The commercial material is sold as a pre-neutralized white powder that hydrates directly in the water phase.
Questions everyone asks
What does this ingredient do in a sunscreen?
It thickens the water phase and stabilizes the emulsion, giving the product a smooth, gel-like feel that spreads easily and does not separate.
Is it the same as an active sunscreen filter?
No. It is a texture and stability agent. It does not absorb or reflect UV light and provides no sun protection on its own.
Will it feel sticky on skin?
References note it is chosen specifically because it builds gel texture without leaving a tacky or sticky residue.