The main difference between the two is that silk is a natural fibre and satin is a synthetic weave that can be made using combinations of threads, either from silk or from other materials, like nylon, polyester or rayon.
Silk is stronger than satin and harder to produce – one thread requires the silk from thousands of silk worms. This also makes it much more expensive to buy. A satin pillowcase made of polyester, for example, will be much cheaper, but will it have the same effects?
If you’re buying satin, you should check to see how many fillers or fabrics are in the weave. The higher the proportion, the less likely it is to protect your hair and skin in the same way as silk does. For satin to give similar benefits to silk, it has to be one of the better quality materials like charmeuse, a finely woven technique.
A fake silk or satin pillowcase will still feel smooth to the touch, but it won’t feel nearly as luxurious as Mulberry silk or be as beneficial as silk bedding. If you are going to buy satin, you won’t have to spend as much, but do make sure you buy the best.