With cold weather and holiday-party makeup wreaking havoc on complexions, revelers might find themselves reaching for sheet masks to soothe their skin and provide a bit of relaxation. The face-shaped, serum-soaked sheets – which typically come one to a pouch and promise hydration, exfoliation or detoxification, among other benefits – have exploded in popularity, linked to a rising interest in Korean beauty products and appearances on Instagram.

“A sheet mask has become an important element of the self-care ritual,” says Larissa Jensen, a beauty industry analyst at market research firm NPD Group who confirmed that, within the prestige category, skin-care face masks have nearly doubled in volume over the past five years, reaching $205 in million sales in 2019.

Along the way, they have also turned into a mainstay within various avenues of wellness culture: Once the purview of high-end and luxury lines and Asian markets, these products now regularly turn up in the checkout aisles of Old Navy and Walmart. “It used to be more unique,” Jensen adds. “Now you can buy them anywhere.”

Ubiquity aside, it’s not clear whether they deliver on the hype. Sheet masks haven’t been the subject of much medical research, and dermatologists see limited benefit.

“The ingredients that are in a sheet mask are often very similar to those in a cleanser, toner, serum or moisturizer,” says dermatologist Arash Akhavan, founder of the Dermatology and Laser Group in Manhattan. As with those products, a sheet mask can have an obvious effect on the appearance of your skin.

For example, a mask containing hyaluronic acid, which draws in moisture, is anti-inflammatory and can diminish the look of fine lines and leave your visage with a glow. The effects, however, are ephemeral. “[Your skin] is hydrated so it appears better, but that’s a short-lived improvement that will fade with time as your skin goes back to its more natural hydration state,” Akhavan says.

In other words: Sheet masks with moisturizing ingredients are like a drink of water for your skin. A glass now doesn’t mean you won’t be thirsty again later.