Everybody and their mom is posting sheet mask selfies on Instagram these days. (Seriously, stop mom.)
, D.O., a New York-based dermatologist, explains what you need to know before you shell out any cash on them.
Sheet masks shouldn’t replace traditional masks.
Don’t let the name fool you: They’re called masks because of their resemblance to thePhantom of the Opera’s go-to accessory, not because they deliver the same benefits as other kinds of face masks. The cotton sheets are doused in a serum-based formula and then placed on top of the skin, so they won’t exfoliate or cleanse deeply.
However, most are packed full of vitamins, amino acids, and minerals—so they do come with their own set of benefits (more on that in a sec). They also won’t dry out the skin like a clay mask formula often does.
They’re best at hydrating. Other benefits…not so much
These liquid-based formulas come in many variations that claim different results—lifting, preventing acne, hiding fine lines—but Palmer says you should only count on them for hydration.
“When you put a mask on your skin, you can increase the water content,” she says. Basically, the paper in the mask seals the ingredients to prevent them from evaporating, letting them better penetrate into the skin (although Palmer says it’s not clear if sheet masks are better than serums at this).
Unless you’re made of $$, don’t use them every day.
“These masks are more of a luxury, used for special events or flying when you have a lot of dryness,” says Palmer. “Used every day, they can get expensive—over $90 a week.” Prices range from a little less than $3 per mask to $20 a mask.
Palmer recommends using a face sheet mask once a week. And since the hydration won’t last more than one day, they won’t completely replace a hydrating serum—so use your serum like you normally would, and think of the mask as a special treatment for added glow.
They’re not always great for people with acne
The occlusion (sealing of the skin) that happens with sheet masks can increase the temperature of your skin, from an average of 89.6 to 98.6 degrees. That’s not ideal if you are prone to breakouts. “Increasing the temperature can increase the bacteria count on the surface of the skin, causing acne,” says Palmer. Certain ingredients in some masks (like eggs or coconut oil) might also clog your pores.
If you have acne-prone or oily skin, Palmer suggests testing the mask on a section of your face, preferably the side of your cheek. Check for new blemishes the next day before proceeding with a full mask. And look for ingredients that are better suited for your skin’s needs, like redness-reducing aloe vera or oil-absorbing charcoal.
Expect to get a little messy
The masks are one-size-fits-all, but not every face is the same size or even the same shape—making fit really damn tricky.
To cover all corners of the face, Palmer suggests beginning at one end: “Start at the forehead, and line up with the eyes so you don’t get an air pocket.”
Pat the mask onto the cheeks, moving down toward the chin. And they don’t always stay on if you’re sitting upright (unless you splurged for the kind with loops that go over your ears), so think of sheet masking as the perfect time to Netflix and chill.
They’re actually pretty sanitary
Despite some scary reports in 2016 that some sheet masks are infested with bacteria(eek!), most masks are totally sanitary because they’re vacuum sealed. And their single-serve packaging makes them super-convenient. Unlike traditional masks that require you to wash your face after using, you can leave the sheet mask’s serum on as your moisturizer for the day—no rinsing required.