Myth 5: Wearing nail polish all the time will make your nails turn yellow.
This is true, but you can wear enamel all you like and still avoid discoloration. Nails are porous, and they absorb the pigment in polishes. "Darker colors, especially reds, have more pigment, so they often stain your nails," says Maria Salandra, the owner of Finger Fitness, in Cliffside Park, New Jersey. The solution: Before applying polish, paint on a clear base coat, such as Essie All in One Base Coat ($10, ulta.com), to prevent nails from absorbing pigment.
Myth 6: You can shrink your pores.
It's actually impossible to change the size of pores, but you can make them look smaller―and using egg whites, a beauty trick Grandma may have tried, does work. "Egg whites tighten the skin, giving the illusion of smaller pores, but it's a temporary effect," says Elizabeth McBurney, a clinical professor of dermatology at Tulane University School of Medicine, in New Orleans.