Ammonium acryloyldimethyltaurate/VP copolymer is a synthetic polymer and film-forming agent that also serves to thicken cosmetic formulas. It is used in small amounts in a number of products due to its stabilizing abilities and aesthetically pleasing feel. https://www.paulaschoice.com/ingredient-dictionary/ingredient-ammonium-acryloyldimethyltaurate-vp-copolymer.html?q=Ammonium%20Acryloyldimethyltaurate%2FVP%20Copolymer&fdid=ingredients