In short, if you want to avoid an ugly-bed head, then switching to the satin pillow covers might be the best idea. More good news – there's another reason why they keep your hair healthy, and that is; they do not suck out all the natural moisture in the hair. Besides, their smooth structure makes sure that your hair doesn't get tangled up while sleeping on them. This is indeed bad news for those who prefer cotton pillow covers. But, you could always go for satin.