Trick question: silk is a fibre; satin is a weave. Silk satin is the real thing; polyester satin is shiny plastic. This is the most useful distinction to know before you buy.
Silk: the fibre
Silk is a natural protein fibre spun by silkworms. The finest grade, mulberry silk, gives long, strong, uniform strands. Because it is a protein - like your hair and skin - silk is breathable, temperature-regulating, moisture-wicking and naturally hypoallergenic. Every Lourel piece, from our silk pajamas to our slip dresses, is 100% mulberry silk.
Satin: the weave
Satin describes how threads are woven: floating warp threads create a glossy face and a matte back. Woven from silk, you get silk satin - the fabric of our heavy satin skirt. Woven from polyester, you get the inexpensive shine sold as "satin" sleepwear - a plastic fibre that traps heat and sparks static.
How to tell real silk from polyester satin
- The label: if it doesn't say silk (ideally 100% mulberry silk), it isn't.
- The price: real silk is never $15.
- The touch test: silk warms quickly against your skin; polyester stays cool and slippery.
- The lustre: silk has a soft, shifting sheen; polyester has a flat glare.
- The burn test (for the curious): silk smells like burnt hair; polyester melts. We suggest trusting the label instead.
Why it matters
The benefits people buy silk for - breathability, moisture-wicking, gentleness on skin and hair - come from the fibre, not the weave. Polyester satin imitates the look but delivers none of them. Read more in our guide to silk sleepwear benefits, and keep the real thing beautiful with our silk care guide.
Browse our silk sleepwear and dresses & skirts - all 100% mulberry silk.