For skin, “smooth with low friction” is often the most important factor, which is why many people choose a silk pillowcase. Real silk is naturally smooth, can feel cool, and may help reduce friction on the face, something some people like if they are prone to sensitivity, redness, or sleep creases.

Satin can also feel smooth, but if it is polyester satin it can feel warmer and regulate moisture less well, which may be less comfortable for some skin types. Cotton satin is softer than regular cotton but it is still absorbent. If your skin irritates easily or you mainly want comfort and temperature regulation, 100 percent silk is often considered the most “luxurious” option.