We spend a third of our lives asleep, but pillows can be the enemy. Cotton...

https://sierra-wiki.win/index.php/Is_Silk_Worth_It_for_Hair_or_Is_It_Just_a_Luxury_Thing%3F

We spend a third of our lives asleep, but pillows can be the enemy. Cotton causes friction, leading to breakage and frizz. Try a silk pillowcase, or simply secure your hair in a loose, low plait before bed to minimise overnight damage