You know how with regular pillowcases you have to keep waking up to flip them onto the cool side? Yeah, that’s not a thing with silk pillowcases—the side you’re sleeping on is *always* cool, which helps you regulate your body temperature as you sleep.
The real selling point of silk pillowcases, though, is how good they are for your hair and skin. The smooth, silky texture reduces friction on your strands, leading to less snagage, breakage, tangling, and frizziness. As for your skin, silk absorbs less moisture than other fabrics, meaning your moisturizer and serum will sink into your skin instead of your pillowcase, which is especially helpful in the winter when your skin is drier.