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Most pillowcases are made from cotton or microfiber, and come included in a set of sheets. You can also buy silk or satin pillowcases, both of which have a smoother texture than cotton and microfiber and are meant to help give you better hair or skin.

Silk pillowcases are made from, well, silk, a natural protein fiber from silk worms that's soft and breathable, meaning it allows air to pass through. Silk is more expensive than cotton and other kinds of fibers, which is why silk pillowcases are likewise more expensive than others.