Solution: Overplucked brows can simply stop growing, says Fredric Brandt, MD, a New York City dermatologist. "Damage to the follicle caused by years of overtweezing and waxing can actually halt hair growth," Brandt explains. Aging and hormones may also be a factor: Just like the hair on your head, brows often thin once you hit perimenopause. So do they sell Miracle-Gro for brows yet? Alas, no-but they’re close. Many dermatologists now prescribe the eyelash-enhancing drug Latisse for off-label use on brows. (Note: A "Latisse for brows" product is reportedly in development but won’t be available for at least a year.) If going the Rx route doesn’t interest you, there are over-the-counter brow conditioners that have been shown to jump-start growth. One cited by several experts: RevitaBrow ($110; revita?lash?.com), which is said to produce results in as little as four weeks. For a strictly cosmetic approach, we like Dalton Brow Fix Natural Brow Gel ($28; qvc.com), a waterproof, tinted gel packed with micronized fibers that cling to the hair you do have, imparting a fuller, natural look that won’t budge or smudge.

Solution: The truth is, most women have slightly asymmetrical brows, says Petrescu, who points out that this problem has become more widespread with the advent of Botox. "Forehead muscles are not predictable, and sometimes injections will cause one brow to spring higher than the other or to become more arched than its mate," she says. The key to making them match again is to work on the lower or less-arched brow. Using a powder or a soft, waxy formula is best, says Paula Dorf, a celebrity makeup artist. "A traditional eyebrow pencil can look cartoonish if applied incorrectly," she says. She also suggests using a stencil that matches your higher or more arched brow to reshape the other. Try: Eliza’s Eyes Brow Definer in Blonde ($28; elizaseyes?shop.com) and Paula Dorf 2+1 for Brows in Brunette ($25; pauladorf.com).