A: You're sounding mighty skeptical; have you been burned lately by hot marketing? A primer—which you apply to your whole face before foundation—can be very useful in helping makeup last. Silicone, one of the most common primer ingredients, provides an adhesive surface for pigment, says cosmetic chemist Ni'Kita Wilson, vice president at Cosmetech Laboratories in Fairfield, New Jersey. A primer also absorbs oil—so makeup is less likely to smear—and fills in fine lines and wrinkles.
Keep in mind: A primer's benefits are cosmetic; when you wash off the product, you also wash off the perfection.