Beauty asked me the following question yesterday:

Thanks for answering my question! What is primer exactly? I thought using moisturizer was enough.

A primer is usually silicone-based, and forms an invisible barrier between your skin and makeup. It can fill in large pores or fine lines, giving you a smoother finish. Its useful for oily skin types because it prevents their foundation and blush from fading, and good for dry skin types because it prevents their makeup from creasing. If you're worried about fine lines and wrinkles but have a fairly even skin tone, you can even use a primer on its own for a more natural look. And, you can also find primers to be used before applying other types of makeup, such as eyeshadows and liners.

Have any of you used a primer? I use them just in the summertime, when my makeup likes to melt off in the hundred degree heat, and it seems to keep me from looking like an oil slick :)