Sleeping Cool in Silk: Thermoregulation Explained

In short: mulberry silk doesn't “cool” the way air conditioning does, but it regulates temperature and doesn't trap moisture — the result is less clammy summer nights and a surface that stays cool to the touch. Here is how it works, and how to choose well.

Is silk really “cool”?

Yes, but not by magic. Silk is a natural, thermoregulating fibre: it helps the body keep a stable temperature, limiting both overheating and chills. Above all, it absorbs very little moisture (around 11%), whereas cotton soaks up perspiration and ends up clinging to the skin. It is this combination — regulating heat and staying dry — that gives that sense of coolness, night after night.

Why silk helps you sleep better when it's hot

Natural thermoregulation

The structure of the silk fibre lets the skin breathe and follows the body's changes in temperature. You are less inclined to search for the “cool side of the pillow”: the surface stays pleasant for longer.

Less sticky perspiration

Because it doesn't store moisture, silk avoids the “damp fabric” effect of warm nights. Sweat isn't held against the skin, which limits discomfort and waking in the night.

A smooth, cool touch

Silk's slippery feel gives an immediate sensation of coolness as you settle into bed — a small detail that changes everything on sweltering evenings.

Silk, cotton or linen in summer?

Let's be honest: for pure ventilation, linen, with its loose weave, lets plenty of air through. Cotton breathes, but absorbs perspiration and warms up. Silk plays a different card: thermal regulation and softness, without the clammy effect — with the added benefits for skin and hair that neither linen nor cotton offer. For many, the ideal summer combination is a silk pillowcase (in contact with the face and hair) on a lightweight bedding set.

Which weight (momme) should you choose for summer?

The momme measures the density of silk. In summer, we favour lightness: 19 momme for bedding remains ideal — dense enough to last, fluid enough to stay airy. For nightwear, 16.5 to 19 momme offers the coolness you are looking for. To understand it all in three minutes, read our momme guide.

Our pieces for cool nights

Begin with the piece that makes the biggest difference on a summer night: the silk pillowcase. Complete it with light silk pyjamas or a nightdress, and discover our full range of mulberry silks. For summer care (more frequent washing), follow our silk care guide.

Discover our silk pillowcases

Frequently asked questions

Does silk really stay cool all night?

Silk regulates temperature and doesn't trap moisture, which reduces the sensation of heat and clamminess. It doesn't actively cool like a fan, but it avoids the “hot, damp fabric” effect of cotton.

Silk or linen for summer sleep?

Linen ventilates more thanks to its loose weave; silk relies on thermal regulation, softness and care for skin and hair. A silk pillowcase on a light bedding set combines both advantages.

Which momme of silk for summer?

19 momme for bedding, 16.5 to 19 momme for nightwear: we look for lightness and fluidity rather than maximum density.

How do you care for silk when you wash it often in summer?

Gentle wash at 30 °C in a laundry bag, mild detergent, dry flat away from the sun. Never in a tumble dryer.