We all know fiber is a critical part of a good diet—but is it also part of a good makeup regimen? Some mascara manufacturers are making "fiber enriched" claims, though the fibers they're talking about are tiny strings of silk, nylon, or rayon, says Ni'Kita Wilson, an independent cosmetic chemist. They cling to the lashes, making them look longer and thicker. Some fiber-rich mascaras (like Lorac Lotsa Lash Fiber Mascara, $19.50, or Lancôme L'Extrême, $24) have these filaments mixed right into the formula—you apply them like any other mascara. Others (such as Talika Lash Extender, $28) are simply dry fibers that come in small glass jars; you brush them on top of your regular mascara (while it's still wet), then lock them in with one more coat. And the newest, ModelCo Fiber Lash ($32, left), is a set: one regular mascara and one tube of linty white fibers to layer in between coats. So far we've been impressed by all the high-fiber lash enhancers we've tried—they give us the kind of length we'd achieved only with professional (and expensive) lash extensions. One warning, however (take special note, contact lens wearers and the sensitive eyed): The dry fibers can start to flake and fall into your eyes by the end of a long day, so you might want to save these products for special (and time-limited) occasions.