A hydrating primer is a cosmetic product applied to the skin before makeup. Its primary purpose is to provide moisture and create a smooth base, helping makeup to apply more evenly and last longer. Hydrating primers often contain ingredients like glycerin or hyaluronic acid, which attract and retain moisture in the skin. In addition to hydration, a hydrating primer can also help to minimize the appearance of pores and fine lines. This makes it a popular choice for individuals with dry or dehydrated skin, as it enhances the overall look and feel of the complexion while preparing it for foundation and other makeup products.