If you already make the effort to put on makeup, you might wonder whether you should use a primer. A primer is like a base coat for makeup. Apply it before putting on your makeup to help products go on more evenly and stay on longer. Primers -- worn under foundation, eye shadows or concealers -- have their benefits and some disadvantages.
Advantages
Primers create a smooth, even surface. They prep your face the way a painter preps a canvas. That smooth base makes it easier to apply foundation or eye shadow evenly, and prevents makeup from settling into fine lines and wrinkles. If you have blemishes or oily skin, a primer absorbs oil throughout the day to keep you from getting shiny.
Disadvantages
Foundation primer is not the best choice for a fresh, natural or dewy-looking complexion. It adds another layer of product to your face and maximizes your foundation, so none of your own natural skin shows through. A full-coverage foundation used with a primer can look very heavy. If you have good skin, you can probably skip the primer.