Silk for sleep: the complete guide

A silk pillowcase costs anywhere between €15 and €120. The photographs look alike, so do the descriptions, and nothing on the page explains the gap.

That gap is real. It comes down to three things — the nature of the fibre, its density, and how the fabric is put together — none of which is visible in an image. Here is how to read them.

Momme: the only number that matters

Momme measures the density of silk. Technically it is the weight in pounds of a piece 45 inches by 100 yards. What matters is simpler: the higher the momme, the denser, thicker and more durable the silk.

The usual benchmarks:

Below 16 momme — too thin for bedding. It is translucent, snags, and tears after a few months of washing. This is the €15-20 range.

19 to 22 momme — the useful zone. At 19, silk holds up properly. At 22, it has the drape, opacity and longevity you expect from quality bedding. This is the standard for premium pillowcases, and the best balance between durability and softness.

25 momme and above — denser still, but the comfort difference becomes marginal while the price climbs sharply. You are mostly paying for weight.

If momme is not stated, it is because it is low. A maker who reaches 22 always says so: it is their argument. A seller who stays vague about density is telling you something without saying it.

Mulberry silk, and the rest

Not all silks are equal, and the word alone guarantees nothing.

Mulberry silk comes from the Bombyx mori worm, farmed and fed exclusively on mulberry leaves. The filament is long, even, and uniformly white. It is the smoothest silk, and the one suited to bedding.

Wild silks — tussah, eri, muga — come from undomesticated worms. The filament is shorter, more irregular, naturally beige. They are beautiful materials, but their surface is less smooth: they lose most of what you are looking for at night.

Above all, be wary of the word "satin". Satin is not a material, it is a weave — a way of constructing fabric. Satin can be silk, but it is far more often polyester. "Satin pillowcase" says nothing about the fibre, and that ambiguity is exactly the point.

The cotton-backing trap

Here is the most widespread trick, and the hardest to spot in a photograph.

Many pillowcases described as "silk" are silk on one side only. The front is silk, the back is cotton or polyester — which halves or thirds the cost.

The problem is not only commercial. You turn over thirty times a night. Every other night, your cheek is resting on cotton, and the whole benefit disappears.

Look for "silk on both sides". If it is not stated, assume it is absent for a reason.

The four tests, once it arrives

Touch. Real silk warms almost instantly against the hand. Polyester stays cool, then turns clammy.

Light. Tilt the fabric. Silk shifts in tone with the angle, with highlights that travel. Polyester shines evenly, slightly metallic.

Crushing. Crush a corner in your hand. Silk keeps a faint crease and a warmth. Synthetics spring back with no memory and stay cool.

Flame, on a thread pulled from a seam — the most reliable test, and the only destructive one. Silk is a protein: it burns like hair, smells of burnt horn, and leaves a black ash that crumbles between your fingers. Polyester melts, smells of plastic, and leaves a hard bead.

What silk actually does

Two things, measurable and modest.

It reduces friction. Silk is a continuous filament — the worm produces it in one unbroken length, over hundreds of metres — so its surface is smooth, without the catch points of cotton spun from short fibres. Hair glides instead of snagging, skin does not drag.

It absorbs little. Cotton can hold a substantial share of its weight in moisture. It draws water and oils out of skin and hair all night. Silk, far less: your evening skincare stays where you put it.

And what it does not do

Silk marketing is saturated with unverifiable promises. Let us set them aside.

Silk does not erase wrinkles. It reduces friction, not compression — the weight of your head against the pillow, which is identical whatever the fabric. And compression is what creates most sleep creases.

It does not make hair grow. Growth happens in the follicle, and no fabric reaches it.

It repairs nothing. Hair is a dead structure: what is broken stays broken. Silk limits future damage; it does not undo past damage.

It treats no skin or scalp condition. If you are losing hair unusually, or your skin reacts, that is a medical matter.

Care, where most silk dies

This is where people ruin their purchase, having never been warned.

Hand wash in cold water, or machine wash on a silk programme at 30 °C, inside a mesh bag. Mild detergent with no enzymes — the enzymes in ordinary detergents break down proteins, and silk is one. It is the most common and most destructive mistake.

No fabric softener, no bleach, no tumble dryer. Dry flat, out of direct sun, without wringing. Iron on low, inside out, if needed.

A well-cared-for 22 momme silk lasts years. The same piece through a tumble dryer once is finished.

Pillowcase or bonnet?

Both act on the same mechanism, in different places.

The pillowcase treats the contact surface: it protects hair and facial skin, and changes none of your habits. It is the simpler choice, and the more effective one for short to mid-length hair.

The bonnet contains the hair. It no longer rubs against anything — not the pillow, not itself, which is the main cause of tangling on long hair. On curly, coily and textured hair it is a long-established practice, precisely because those textures are the most vulnerable to friction.

The two are complementary: the bonnet for hair, the pillowcase for skin.

In short

Insist on momme, and aim for 22. Check it is mulberry silk, and that it is present on both sides. Be wary of the word "satin". And wash cold, without enzymes, never in a tumble dryer.

Our answers

Silk Pillowcase — 100% mulberry silk, 22 momme, on both sides, 51 × 76 cm, invisible zip.

Silk Sleep Bonnet — soft elasticated edge that holds without marking your forehead.

Read more

Tangled hair in the morning: what eight hours of friction does to it
Why you wake up with lines on your face
How to choose a pillow: the complete guide