Thicker eyebrows are making a comeback for fall, but there is a fine line between a Brooke Shields-style arch and heavy brows that look, simply, unkempt. To help amateurs achieve the former, a host of brow-specific products have recently hit the market.

Several of those items promise to give the illusion of a fuller brow. Bare Escentuals’ A-List Brows kit ($45) contains brow color, a highlighter, brow gel, tweezers, and an angled brush, as well as instructions. Lorac’s Take a Brow kit ($22) includes two powder brow colors, a clear wax, and a mini-angle brush. And later this year, Anastasia Beverly Hills will launch its Best in Brow grooming kit ($44), which includes brow stencils, a brow pencil, wax, and a cream highlighter.

To help truly sparse brows, Anastasia recently came out with a brow enhancing serum called Nú Brow ($35) that vows to restore, reshape, and condition overplucked eyebrows. According to the company, it is selling an average of 1,000 units a week at Sephora stores.

The right tools can also help to achieve the look. A makeup artist and eyebrow-shaping expert at Slope Suds Salon in Park Slope, Elke Von Freudenberg, said her favorite brow product is an angled brush — “the tiniest, smallest angle brush you can find.” Two of the best, she said, are Benefit’s Hard Angle Brush ($14) and Sephora’s Professionnel Platinum Angle Brush #22 ($18). She prefers powders to pencils, but adds that if your eyebrows are balanced in color and shape, neither is needed.

Estée Lauder model Hilary Rhoda, known for her prominent, expressive arches, is able to pull off the look. And the actress Sienna Miller appears on the cover of the September edition of Vogue with darker, heavier brows, but experts say that not every woman should follow the trend.

“Brows should suit your face,” a makeup artist for Benefit, Arianne Damboise, said. “You don’t want to have a brow arch that doesn’t complement you — it’s like wearing a color of clothing that clashes with your skin tone.”

Earlier this year, Benefit opened a “brow bar” at its counter in Bloomingdale’s, offering browshaping services to go along with its extensive collection of brow products. On a recent visit, my brows were treated to a gentle waxing and tweezing to even out my arches, then finished with a swipe of High Brow highlighter pencil ($18) and clear Speed Brow gel ($16). Benefit is one of several cosmetics companies that are taking eyebrow grooming of the salon and into stores.

Despite some new competition, brow specialty salons say business is booming. “Magazines and television have heightened awareness of eyebrow grooming,” the owner of three Shobha threading-specialty salons, Shobha Tummala, said. “From the Gotti brothers to makeover shows, images in the media have illustrated that simple and quick eyebrow grooming can improve anyone’s entire appearance.”