"Um, aren't you going to get that all over your pillow?" asked my boyfriend with a raised eyebrow. I had just emerged from the bathroom with a face slathered in cream à la Mrs. Doubtfire's Cool Whip pie incident. Not my sexiest look. But I was on a mission for baby-soft skin and more than willing to endure a little goop.

Let me explain. This latest beauty craze comes from South Korea. Forget Psy (if I hear “Gangnam Style” one more time…). This trend has nothing to do with K-pop. The Asian beauty buffs who popularized BB creams have spearheaded an entirely new skin-care trend: the sleep mask. Not to be confused with the flimsy satin eye covers you get on transatlantic flights, these unique gel and cream masks are made to work with your skin’s natural rhythm at night.

“The trend originated in Asia because, for Asian women, hydration is key,” explains Sarah Gora, medical and scientific relations leader for Vichy Canada. Skin hydration is also a big concern for Canadian women, especially during winter months when indoor heating and cold outdoor air strip the skin’s hydrolipid film, says Gora. After our conversation, I test-drove Vichy’s Aqualia Thermal Night Spa sleeping mask, and the blue gel quickly absorbed into my tired, moisture-sapped skin. The formula is made of Vichy’s thermal spa water and a trademarked hydrating ingredient called Aquabioryl. Most importantly, it contains a high concentration of hyaluronic acid, a substance that’s naturally present in the body and can hold up to 1,000 times its weight in water, making it the perfect ingredient for hydrating sleep masks.

But why do you need to leave it on all night? Reached by phone from Zurich, Daniel Stangl, director of innovation for La Prairie, gives me the lowdown on the underlying science.

“During the night, you’re not exposed to environmental aggressors,” says Stangl. “In the last 20 or 30 years, we’ve learned much more about this day-and-night shift between skin functions.” Like the rest of your body, the skin has a circadian rhythm—a 24-hour cycle of physiological processes. During the day, you’re in protective mode against the environment, with increases in oil and sweat, whereas at night, oil production slows and blood flow and skin temperature increase. Nighttime is regeneration mode, when cells grow and renew themselves. This might explain why recent research suggests that troubled sleepers age faster and have slower recovery times when exposed to environmental stressors like sun damage—they’re not giving their bodies (or skin cells) enough time to rest and recharge.

Your skin also loses moisture at night. Or, to put it in scientific terms, you suffer higher trans-epidermal water loss because there’s more of an exchange between the skin and the air that Stangl describes as a form of breathing. With active ingredients such as caviar extract, sunflower seed oils, peptides, Carica papaya, Salicornia extract and cupuaçu seed butter, products like La Prairie Skin Caviar Luxe Sleep Mask can help lock in moisture and make the most of your skin’s nocturnal renewal. Stangl recommends using a sleep mask one to three times per week, depending on your skin’s needs.

How do you avoid gunking up your sheets and pillow? “That’s a very good question,” laughs Stangl. But I needn’t have worried. Minutes after applying an ample layer of creamy La Prairie mask, it had fully absorbed, aside from an almost invisible film that didn’t get on my pillow or my boyfriend, and left me with more supple skin upon waking.

Dream creams:

1. Clinique Moisture Surge Overight Mask, $38, clinique.com.
2. SkinCeuticals Hydrating B5 Masque, $64, skinceuticals.com/canada.
3. Vichy Aqualia Thermal Night Spa, $44, vichy.ca.
4. Korres Greek Yoghurt Advanced Nourishing Sleeping Facial, $59, korres.ca.
5. La Prairie Skin Caviar Luxe Sleep Mask, $365, holtrenfrew.com.


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