What you need to know about these popular devices.

Long gone are the days when washing your face required just a good cleanser and washcloth. Now, no self-respecting beauty buff’s skincare arsenal is complete without a sonic facial cleansing brush, which employ an oscillating brush to deep-clean pores, exfoliate, and polish the skin’s outer later to a seemingly healthy glow. 

But in spite of the rising popularity of devices from reputable brands such as Clarisonic and Clinique, experts remain divided on their skin benefits. New York-based dermatologist Elisabeth Shim, MD, argues that these gadgets can worsen skin conditions in some patients. “Acne vulgaris patients with whiteheads or pimples can make their acne worse by stimulating inflammation with this type of device,” says Shim. 

An early adopter of the Clarisonic, facialist-to-the-stars Kate Somerville not only incorporates the handheld device into all facials out of her West Hollywood clinic (where the likes of Jessica Alba and Kate Hudson are regulars), but also uses it on her own eczema-prone complexion. “I love it, and see a lot of patient’s skin turn around—especially since it incorporates a level of exfoliation, so everything works better.” 

While Shim agrees that all the exfoliation makes active ingredients penetrate skin faster, she also points out that irritation from certain acne medications (like tretinoin, retinols, and benzoyl peroxide) can increase as well. “Rosacea is worsened by anything that brings flushing to the skin,” she adds. “It is a reactive condition, so I have seen problems with that as well.”

In addition, some aestheticians are wary of the brushes’ bacteria-prone nature. “I’m a huge germophobe,” says the Los Angeles-based facialist Alexandra Wagner, citing that bacteria problems can lead to further skin complications. The new Michael Todd Soniclear promises antibacterial protection but for other devices, Somerville recommends sanitizing after each use with witch hazel or alcohol, as well as proper storage in a dry place. “If you keep it in your shower, make sure it’s not sitting face down in a puddle of water,” she adds.

Like Shim, Somerville does caution against overuse, and recommends more gentle brush heads for patients with skin problems. Clarisonic’s Cashmere Cleanse face brush head was designed especially for sensitive skin types. Somerville also suggests using a gentle face wash, such as her own Detox Daily Cleanser (packed with anti-inflammatory phytic acid to keep skin from flaring up). “I teach my clients: If you’re having issues, cut down usage to just 3 times a week, don’t use it as long, and use it with a cleanser you know is not going to irritate your skin.”