Free shipping and returns on slip™ for beauty sleep 'Slipsilk™' Pure Silk Pillowcase at Nordstrom.com. This anti-aging, anti-sleep crease, anti-bed head pillowcase by slip for beauty sleep is like an eight-hour beauty treatment every night. Crafted from pure silk inside and out as recommended by dermatologists, plastic surgeons, hairdressers and beauty experts alike, this pillowcase elevates beauty sleep to a whole new level.We spend a third of our lives in bed, so what you sleep on is important. Silk fibers are significantly less absorbent than many other fibers, so they help keep your skin’s moisture and expensive face and hair products where they belong—on your face and hair, not your pillow. Ordinary pillowcases can cause hair to pull and tangle throughout the night, leading to bed head in the morning and potentially damaging hair. Slipsilk can help reduce friction, too, which also aids in reducing stretching and tugging on delicate facial skin.