The first time I ever experienced ultrasound during a facial was around six months ago, on aesthetician Mashell Tabe's table. She coated my skin in a thick layer of conductive gel solution, then ran the small, flat disc attached to a wand slowly around my face — yes, exactly as though she was searching for signs of a fetus in there. (Spoiler alert: She didn't find one.)When the device hit my temples, there was a faint ringing vibration in my ears, and when it was near my mouth, I experienced a slight tingling, but for the most part, it just felt like a smooth, cool stone was being rubbed all over my face. Only a smooth, cool stone wouldn't leave my skin with the crazy glow this device did.Since then, the two other facials I've received (most notably, the amazing one at the Erno Laszlo Institute ) have also harnessed the power of ultrasound — which isn't new, but certainly is trendy — and I don't think it's a coincidence that my complexion looked better after those treatments than after any other facial service I've ever received. What gives? I reached out to the pros to get the scoop.But first, let's back things up a bit: There are three levels of ultrasonic therapy popular in the beauty world. There's the facial add-on, which is the one I've been getting and is painless, works over time, and is something you could do every day with a handheld device. (Most at-home versions, like the Nurse Jamie ACELLerator Ultra cost around $200-300). Then there's Ultherapy, a non-invasive, FDA-approved treatment for tightening and lifting the brow, neck, and chin areas nearly instantly by heating up deep layers of tissue. (It's not-so-painless — and it's got a price tag in the thousands.) And finally there are treatments, like Liposonix and UltraShape , that use ultrasonic technology to destroy fat cells. (Also painful and expensive.) We're talking about the first one.Ultrasonic therapy uses high-level sound waves — far beyond the range audible to humans — to stimulate cells far beyond the superficial layers of skin, which jumpstarts collagen production, reduces inflammation, and promotes blood circulation (hence, the glow). "It’s a gradual process," says celebrity facialist Cecilia Wong , "but when combined with another therapy, like microcurrent, it targets both the skin tissue and muscles on a far deeper level, producing optimal results." Aesthetician Shani Darden , who uses ultrasound devices in all her treatments, is also a fan. She says that over time, it can smooth out fine lines and wrinkles and tighten the skin for a more youthful appearance.Collagen stimulation is nice and all, but far from instant — and that's where the immediate results come in. Tabe loves sonic-wave treatment for its exfoliation and peel-like properties, its power to push nutrient-rich serums deeper into the skin, and how it deep-cleans pores — all without irritating your skin. (Even those with rosacea and especially sensitive skin won't react or get red.) "The vibrations generate a reaction in the skin, which gently and thoroughly lifts dead surface skin cells and pigmentation, and cleans out follicles without the irritation and inflammation," she says. In other words: Think of it as microdermabrasion-lite. Plus, high-frequency waves have been shown to kill 99.9% of bacteria, so it's especially good for those with acne.After an intense facial in March that left me with painful cystic pimples for weeks, I've sworn off extractions, harsh chemicals, and even aggressive massage techniques. That's why I'm loving the results of the device: Post-appointment, my skin still feels clean, bright, and toned, but never attacked. Ultrasound: for looking at babies and looking like one.