Methyl methacrylate crosspolymer is a copolymer of methyl methacrylate crosslinked with glycol dimethacrylate. In cosmetics and personal care products, methyl methacrylate crosspolymer functions as a film former and viscosity increasing agent. It is used in various types of makeup, particularly eye makeup, as well as skin, hair, and nail care products.

As a film former, methyl methacrylate crosspolymer leaves a thin, pliable film on the surface of skin or hair after application. The film has strong hydrophilic properties and provides a smooth feeling to the skin/hair. Methyl methacrylate crosspolymer also functions as a viscosity increasing agent. The term viscosity corresponds to the concept of “thickness”, for example, honey has a higher viscosity than water. Therefore, as a viscosity increasing agent, methyl methacrylate crosspolymer works to thicken formulations in order to make a product less runny and easier to spread.

Methyl methacrylate crosspolymer is too large to penetrate the skin and the polymer contains low levels of monomer, which means that it is unlikely to cause dermal sensitization. Therefore, methyl methacrylate crosspolymer is considered to be safe as used in cosmetics and personal care products.