The main reason is less friction. Silk is smooth, so hair is less likely to rub, tangle, or frizz, and hairstyles often stay neater for longer with a silk pillowcase. For skin, the gentle glide can feel more comfortable, and some people notice fewer sleep creases or less irritation.

Silk also often feels cool and luxurious, which can improve overall sleep comfort. It is mainly a comfort and hair care choice, not a guaranteed fix for acne or hair loss, but it can support your routine.

Pay attention to quality and care. Look for 100 percent silk with a suitable momme weight, and wash gently with mild detergent and not too hot water. If you want to see whether it helps you, start with just one pillowcase and compare for a few weeks.