The beauty secret of celebrity hairstylists, dermatologists and beauty experts. We spend a third of our lives in bed. In laboratory testing, Slip pure silk pillowcases were shown to absorb significantly less face cream than cotton pillowcases, so they can help keep your skin's moisture and valuable face and hair products where they belong — on your face and hair. Made using Slipsilk, it was also shown to create 43% less friction on average, which can reduce stretching and tugging on delicate facial skin.