Curious about what LED red light therapy does? Us too! Luckily, celebrities who have long used the treatment in-office and at home have spilled on some of the benefits, and there’s plenty of research to back up the claims.

Wellness pioneer Kourtney Kardashian posted a photo of herself wearing a $2,000 glowing mask on Instagram way back in 2016, at an appointment with celebrity aesthetician Shani Darden. (Another client of Darden’s? She-of-the-most-glow, Jessica Alba.) Since Kardashian shared that pic, plenty of other stars, including Chrissy Teigen, Kelly Rowland, Lena Dunham, Emma Stone and Real Housewives of New York City’s Carole Radziwill have posted images of similar red and blue light facial therapy sessions. Others, including Olivia Munn, have told Us they have their own equipment set-ups at their houses.

Since Kardashian and Alba shared their first photos, at-home LED light therapy devices have hit the market in growing numbers and at different price points. As Arizona-based aesthetician Cherie Callahan, who’s long used LEDs in her practice tells Us, red light therapy penetrates the skin and works by “increasing blood flow and oxygen, the food of cells.” This speeds up cellular processes including cell turnover while helping to decrease inflammation and enhance collagen. Translation: Reduced fine lines and wrinkles as well as more supple skin. (The spectrum doesn’t include UV light, so exposure is safe.)

Workout warriors are in luck too. The technology has expanded past visage-focused masks to handheld devices and house-friendly hanging panels, which means that you can also direct the light elsewhere on your body to help treat inflammation, joint soreness and muscle aches. To that point, we’re partial to the Red Light Therapy Panel, a $295 rechargeable, wireless device we recently tested out. (Pro-tip: It’s easy to combine a morning face-plumping session with a daily meditation practice.)

The benefits that red light and near infrared light (NIR) therapy have on the body work in a similar way, as many pro athletes have discovered. “The two most important are the effects on increasing energy within the cell, which in turn allows the cell and the organ to have more energy to perform its function and repair,” Ara Suppiah, M.D., an assistant professor at the University of Central Florida Medical School and an emergency and sports medicine physician, tells Us Weekly. “For example,” he adds, “increased energy within a muscle cell allows it to contract harder and repair itself after training.” Treatments done in-office tend to be more powerful, but at-home devices can help you maintain between session or just give a little boost on their own.

Scroll through to see the celebrities who have used LED light therapy and hear what they have to say about how it helps them!

She’s a real glow-getter! “I have my own facial set up, I’ve got the professional-grade products and machines, and any girlfriend that comes over to the house, I love doing facials with them,” the Rook actress told Us in October 2018. “But one of the best things is the red and blue light mask. The [red] light helps develop collagen and repair things inside, and the [blue] light is good for killing bacteria and things like that. And I keep a zapper with me whenever I go anywhere, because if you get a little pimple here or there, just zap it off.”

In October 2018, the Cravings cookbook author Tweeted a video of herself doing an at-home LED session. In classic Teigen fashion, the video turned comical, as she tried and failed to drink wine from a straw through the mouth hole of her mask.

The Victoria’s Secret Angel likes to get a facial from aesthetician Tracie Martyn before big events. “It just makes my skin feel tighter and more lifted,” Hunt told Us in September 2018. “Whatever that red light therapy is, I don’t know if it’s placebo, but I feel great afterwards.” The model added it helps her zen-out too: “I feel so calm during their facial, afterwards too. I could just go to sleep.”

In May 2018, the RHONY star and journalist told Into the Gloss that red light therapy is part of her skincare routine. “I have the red light from LightStim, and I binge all those crime dramas so whenever I do that, I’ll just sit there with it on for an hour,” she said. “It’s kind of awkward if your boyfriend’s over, but really if he’s not into red light I’m not into him.”

In January 2017, the Hills alum told Us she stays away from Botox, but has another anti-aging trick. “I use red light therapy twice a week to prevent lines and wrinkles,” she said.

The Girls creator got into light therapy in December 2016. “Saw the ad for the light therapy acne mask and became obsessed so when we got home from our journey it was waiting on my side of the bed. Thank you @jackantonoff, even if you just did it to amuse yourself,” she wrote on Instagram. (The Neutrogena mask she was using in her Instagram photo was later recalled due to the risk of eye damage.)

The Oscar winner shared a photo of herself with the later-recalled Neutrogena LED light therapy mask (and reportedly gave them to friends as gifts!).

The Fabletics founder was an early adopter of LED light therapy, as her Pilates trainer Nicole Stuart shared on Instagram in May 2016. When Stuart texted that she was caught in traffic before their appointment, Hudson simply texted back a photo of herself in pajamas with a glowing red visage with the text “All good.” Quipped Stuart, “This is what I walk into when I’m running late for @katehudson.”

The eldest Kardashian sis posted an LED light treatment photo to her Instagram in March 2016, using aesthetician Shani Darden’s $2,000 at-home device, which wasn’t yet available to the public. “The [red] light helps to reduce fine lines and wrinkles and boost collagen in the skin,” Darden told Us at the time. “It also has blue light, which kills acne bacteria.”

After taking over the Instagram account for O: The Oprah Magazine in December 2015, Rowland signed off with a photo of her in a light therapy session. This is how I’m winding down my day,” she wrote.

In September 2015, Alba let her Instagram followers know, via a glowing facial photo, that she was into LED light therapy.