A mattifying primer is a cosmetic product designed to create a smooth base for makeup application while controlling shine. It typically contains ingredients that absorb excess oil, helping to reduce the appearance of pores and create a matte finish on the skin. This makes it particularly beneficial for those with oily or combination skin types. When applied before foundation or other makeup products, a mattifying primer can enhance the longevity of the makeup, preventing it from sliding off or becoming shiny throughout the day. Many brands offer mattifying primers, often formulated with silica or kaolin clay to achieve the desired effect.