What Is a Silk Sleep Mask? Mulberry Silk and Momme Explained

This guide is about what you are actually buying: where mulberry silk comes from, why "satin" is not the same thing, what the momme number means, and how to look after the mask once you have it. Curious why people choose silk for sleep in the first place? That is covered in a separate post on silk mask benefits.

What Is a Silk Sleep Mask Made Of?

Silk is a protein fibre that comes from the cocoon of the Bombyx mori silk moth. Textile researchers at Queensland University of Technology describe it as the only natural filament fibre used in textiles on a large scale. A filament is one long, continuous strand, rather than lots of short fibres twisted together like cotton.

Why It Is Called Mulberry Silk

Most of the world's commercial silk comes from domesticated silkworms raised on mulberry leaves, which is where the name comes from. So "mulberry silk" is not a special finish or a brand name. It tells you the silk comes from cultivated Bombyx silkworms rather than from wild silk moths, a background covered in Britannica's history of silk.

Silk Is a Fibre, Satin Is a Weave

This is the mix-up that catches most shoppers. Silk is what the fabric is made from. Satin is how it is woven. Britannica explains that satin was first made from silk but is now made from other fibres too, which is why a "satin sleep mask" is often polyester. It can look glossy and feel smooth, but it is not silk.

UK labelling rules back this up. Trading Standards guidance on labelling textiles says the word "silk" must not be used to describe the texture of any other fibre. A product described as "silky" or "silk-feel" is telling you it is something else.

What Does Momme Mean on a Silk Sleep Mask?

Momme (pronounced "mummy") is the standard way of measuring how heavy and dense a silk fabric is. The word started life as a Japanese unit of weight. In silk it works like grams per square metre does for other fabrics: the higher the number, the more silk is packed into the cloth.

A guide from scales maker Adam Equipment puts 8 momme at roughly 35 grams per square metre and groups silk into three bands: lightweight under 20 momme, midweight from 20 to 28, and heavyweight above 28. Working from those figures, 19 momme comes to around 80 grams per square metre.

Where 19 Momme Sits

The 3D mulberry silk mask from Nyla Rest is 19 momme, which puts it at the top of the lightweight band. We say that plainly because momme is often used as a selling point without being explained. Heavier silk uses more fibre and feels thicker in the hand. Lighter silk is thinner and less bulky against the face. Neither is right or wrong. What matters is that the number is stated, so you can compare like with like.

How to Read a Silk Sleep Mask Label

Here is what the most common label wording actually tells you.

Flat or 3D: Which Shape Is Right?

A flat silk mask is a single soft panel that rests directly on your closed eyelids. A 3D silk sleep mask has moulded cups that curve away from the eyes, so the fabric sits on your brow bone and cheeks instead.

• Choose 3D if you dislike anything touching your eyelids, wear lash extensions, or like to open your eyes under the mask.
• Choose flat if you are a side sleeper and want the thinnest possible profile against the pillow.
• Either way, check for gaps at the bridge of the nose, which is where light most often gets in, and pick an adjustable strap so you can wear it loosely.

The Nyla Rest mask is the 3D style, with an adjustable strap.

Do You Need a Sleep Mask at All?

Start with the room. The NHS Every Mind Matters sleep advice suggests a quiet, dark and cool bedroom, closing curtains fully, and keeping clocks and phones out of sight. It then suggests wearing an eye mask if light is still a problem.

That is the right way to think about a mask: a simple answer to light you cannot otherwise control. Early summer sunrises, a partner reading late, a streetlight through thin curtains, a hotel room or a long flight are all good reasons. A silk mask is not a sleep treatment, and it will not fix poor sleep on its own. If light is only one of several things keeping you up, the Deep Rest Set pairs this mask with a Steam Eye Mask and a pack of Sleep Patches.

How to Wash a Silk Sleep Mask

Always read the care label first. As a general rule, silk is a delicate protein fibre, and the QUT textile researchers mentioned earlier suggest a gentle approach:

1. Use cool or cold water. Hand washing is the safest option for a small item like a mask.
2. Choose a mild wash. A detergent made for silk or wool, or a very mild shampoo such as baby shampoo.
3. Do not wring it. Twisting can damage the fibres and leave creases.
4. Press out the water. Lay the mask between two towels and press gently, then let it dry flat or hanging.
5. Keep it out of the sun. Store silk away from direct sunlight. If you need to iron it, use the lowest setting with a cloth in between.

Between washes, keep the mask in a pouch so it stays clean and does not snag. The Nyla Rest mask comes with its own matching mulberry silk pouch for this.

Before You Buy

Is a silk sleep mask the same as a satin sleep mask?

No. Silk is a natural fibre and satin is a type of weave. A satin mask can be made from silk, but most are polyester. Check the fibre content on the label.

Is mulberry silk the same as pure silk?

Not quite. "Mulberry" tells you where the silk came from. "Pure" is a labelling term that, in the UK, may only be used when a product contains one fibre.

What momme is best for a sleep mask?

There is no single best number. Lighter silk feels thinner, and heavier silk feels denser. The important thing is that the momme is stated so you can compare masks fairly.

Can a silk sleep mask go in the washing machine?

Follow the care label for your mask. When in doubt, hand washing in cool water with a mild silk or wool detergent is the gentlest option.

Will a silk sleep mask help me sleep?

A sleep mask blocks light. The NHS lists an eye mask as one option when light is keeping you awake, alongside a dark, quiet and cool room. Long-term sleep trouble is something to raise with your GP.