"Silk pillowcase" has been a wellness-shop staple for long enough that it is easy to assume the claims are marketing. Some of them are. A few of them are not, and the difference comes down to friction and moisture.
What it genuinely does
- Less friction on hair. Cotton grips hair and drags it as you move; silk lets it slide. Over weeks that means less breakage at the ends and fewer mornings waking up with a bird's nest. If you go to bed with damp hair, or a blow-dry you want to keep, this is the real benefit.
- Fewer sleep creases. The same low friction means your skin is pushed around less overnight, so the lines you sometimes see on your cheek at 7am fade faster.
- It stays cool. Silk does not trap heat the way cotton flannel or polyester does, so if you sleep warm, it helps.
What it does not do
It will not fix acne, it is not skincare, and it will not do much if your hair routine is the actual problem. It is a small, pleasant upgrade, not a treatment.
The bit that matters when buying
Momme (mm) is the weight of the silk. Below about 16mm it is thin and wears out fast; 22mm and up is heavy and expensive. 19 momme is the sweet spot: substantial enough to last, still cool all night. Ours is 100% mulberry silk at 19 momme, OEKO-TEX certified, with a hidden zip so nothing catches.
If you would rather have linen
Linen does the opposite job: matte, textured, breathable, and it looks better a little rumpled. We wrote about the choice in silk or linen. Plenty of people keep a silk one and a linen one and switch by season. Both ship free worldwide, and there is a wind-down routine that uses one in a wind-down routine that actually sticks.