What's the difference between Silk and Satin?
Stand in a homeware aisle and silk and satin look like twins. Both are smooth, both catch the light, both promise better hair and fewer creases by morning. They are not the same thing, though, and the difference is simpler than the marketing makes it sound.
The one distinction that explains everything
Silk is a fibre. Satin is a weave. Silk is a natural protein thread spun by the silkworm. Satin is just a way of weaving threads so the surface comes out glossy and smooth, and you can weave it from almost anything. These days it is usually polyester. So the word "satin" tells you how a fabric was made, not what it is made of. "Silk" tells you the actual material. That gap is why a satin pillowcase can cost a fraction of a silk one. Quite often it is polyester wearing a nicer word.
Where the difference actually shows up: your skin and hair
On looks alone, the two are close. Against your skin overnight, they part ways. Silk is a protein, much like your hair and skin, and it breathes. It wicks a little moisture, helps regulate temperature, and stays cool rather than clammy. Dermatologists point to silk's low friction too. Less drag on the pillow means less tugging on hair and less creasing pressed into skin, which is part of why silk gets recommended for sensitive and acne-prone skin. Polyester satin is smooth, but it does not breathe the same way. It tends to hold heat and moisture against you, which is the opposite of what you want at 3am in an Auckland summer.
The honest case for satin
Satin is not the villain here. It is cheaper, often by half or more. It machine-washes without a second thought. It is vegan, if that matters to you. And a good satin pillowcase still beats a rough cotton one for your hair. If budget is the deciding factor, satin is a reasonable place to start. You are trading breathability and longevity for price, and for some people that is exactly the right trade.
How to tell which one you are holding
Price is the first tell. If a "silk" pillowcase costs less than a takeaway dinner, it is almost certainly polyester satin. Then look for the word momme, the measure of silk's weight and density. Real silk lists it. Satin never does. Hold the fabric to the light: silk has a soft sheen that shifts colour as you turn it, while polyester shines the same flat way from every angle. For the full set of tests, our guide to silk momme goes deeper.
So which should you sleep on
If you want the cooler, gentler, longer-lasting option, and you are happy to hand-wash now and then, silk earns its keep. If you want most of the smoothness for a quarter of the price and would rather not think about laundry, satin is fair enough. Just buy it knowing what it is. "Satin" describes the weave, and the fibre underneath is usually polyester.
Comparing silk to polyester specifically, rather than to satin? We pull those two apart in silk, satin and polyester. And when you want to feel the difference, our silk pillowcases are 22 momme, 100% mulberry silk.
Source: dermatology research on pillowcase friction and skin, summarised in GoodRx's dermatology overview.