Is ice silk real silk? What it's made of, and how to tell real silk

In short: no, ice silk is not real silk. It is a trade name for a fabric that feels cool to the touch, and the fiber inside varies: rayon (viscose), polyester or nylon, often blended with spandex. The textile firms that make and sell it describe it first as rayon. The listings we opened say polyester: on 27 September 2026 we checked eight products sold as soie glacée, French for ice silk, on Amazon France. Seven declared polyester or polyamide (nylon), the eighth named no fiber at all. None declared silk. To know what you are buying, read the fiber content, not the product name.

On a product page, "ice silk" sounds like a kind of silk: cooler, lighter, made for summer. You find it on underwear, motorcycle balaclavas, UV gloves, cooling mats for dogs, summer blankets and sleep masks. The word "silk" is there. The silk is not.

What is ice silk fabric made of?

"Ice silk" is not a fiber name. It is a selling name that describes a feeling: a thin, smooth fabric that feels cool when you touch it, sold as "cooling" or "breathable".

What is actually inside depends on who you ask.

• The textile trade says rayon. Chinese textile trader Yutai writes (in French) that ice silk was originally just a trade name for a modified viscose fiber, and that today's fabric is often blended with modified polyester, nylon or spandex. Starketex, a Chinese fabric maker, writes that most ice silk fabrics are made from viscose, that is, regenerated cellulose.
• The listings we read say polyester and nylon (table below).

Testex, a Chinese maker of textile testing equipment, puts it plainly: "'Ice silk' is not a fabric component, but a product that merchants use to promote fabrics or clothing". It lists polyester, viscose, spandex, nylon, modal and cotton blends as possible materials.

So, is ice silk polyester? Often, but not always. Rayon or polyester, the answer changes from one label to the next. One thing does not change: it is not silk.

What the Amazon France listings declared, 27 September 2026

Product sold as "ice silk"	Declared composition
Motorcycle balaclava	Polyester
Boxer briefs, pack of four	85% polyamide, 15% elastane
Mesh boxer briefs	Polyester
UV-protection gloves	Polyester
Cycling caps	92% polyester, 8% elastane
Boxer briefs sold as "luxury"	78% polyamide, 22% elastane
Night caps and an eye mask	Polyester, nylon
Sleep mask	"Ice silk, fabric": no fiber named

Polyamide is nylon: EU law lists both names for the same fiber. Elastane is the European name for spandex. Rayon, also called viscose, is a semi-synthetic fiber made from regenerated cellulose, from sources such as wood. None of them is silk.

Why ice silk feels cool

The cool feeling can be measured. Textile labs press a plate heated to skin temperature onto the fabric and record how much heat it draws away in the first moment: that peak is called q-max, in W/cm². Intertek, which runs the test under the Chinese standard GB/T 35263, sums it up: the higher the q-max, the cooler the fabric feels.

Testex gives the reasons. On first contact, the fabric is cooler than your skin and draws heat from it. Some fibers, such as nylon, conduct heat well and carry it away faster. Regenerated cellulose fibers, such as rayon or modal, pull sweat to the outside of the garment, where it evaporates.

Polyester, on the other hand, takes up very little moisture. The conventional values in ASTM D1909, the standard used to trade fibers, are 0.4% of their weight for polyester and 11% for silk.

Testex adds two limits. The chill is not permanent: "it lasts up to 3-5 seconds". And polyester "performs awfully in breathability", which is why polyester ice silk sheets can end up feeling hot. Treated cooling fabrics, it adds, can in many cases weaken noticeably after 5 to 10 washes.

Ice silk vs rayon vs real silk

Criterion	Polyester or nylon ice silk	Rayon ice silk	Silk
Fiber origin	Synthetic	Semi-synthetic: regenerated cellulose	Protein spun by the silkworm
Moisture regain (ASTM D1909)	0.4% (polyester)	Highly absorbent, no figure checked here	11%
Burn test (one thread)	Melts, hard black ash, sour smell	Flares up, almost no ash, paper smell	Burns slowly, self-extinguishes, crumbly ash, burnt-hair smell
What the label says	"Polyester", "polyamide" or "nylon"	"Viscose" or "rayon"	"Silk", sometimes "mulberry silk"

What EU law says about the word "silk"

We are a French brand, so our reference is EU law: textile labeling falls under Regulation (EU) No 1007/2011. Four passages are enough to understand the issue.

• Annex I defines silk, under number 4, as "fibre obtained exclusively from silk-secreting insects", in other words from silkworms.
• Article 5(1): "Only the textile fibre names listed in Annex I shall be used for the description of fibre compositions on labels and markings of textile products."
• Article 5(2): "The names listed in Annex I shall not be used for other fibres, whether on their own or as a root or as an adjective." And, more specifically: "The term 'silk' shall not be used to indicate the shape or particular presentation in continuous filament yarn of textile fibres."
• Article 16: the fiber composition "shall be clearly visible to the consumer before the purchase, including in cases where the purchase is made by electronic means".

The word "satin" does not appear once in the regulation. Satin is a weave, not a fiber: a satin can be silk, polyester or viscose.

Article 16 is the one to remember. On a shopping site, the composition must be shown before you buy. That line is what counts, not the product name.

How to tell real silk

1. Read the fiber content, not the title

Look for the "composition" or "material" line on the listing, or the sewn-in label. Silk states itself in plain words: "100% silk", sometimes "mulberry silk". Words in a title, "silky", "silk touch", "satin", "ice silk", do not describe a fiber. If the composition is missing, ask the seller before you buy.

2. The burn test, on a single thread

It is one of the simplest tests you can do at home. Take a loose thread from an inside seam or an offcut, never from the visible fabric. Hold it with tweezers over a sink, away from anything flammable. Burn a warp thread and a weft thread separately: a fabric can mix two fibers, silk and viscose for instance, without it showing.

• Silk burns slowly, with a small flame that goes out on its own very quickly. Its greyish ash crushes easily between the fingers and smells of burnt hair or feathers. That makes sense: silk is a protein, like hair.
• Rayon (viscose) catches all at once, with a yellow flame, like cotton, and leaves almost no residue. The smell is faint, like burning newspaper.
• Polyester seems to melt and crackles a little. It leaves a black ash that is hard and shiny once cooled, and a sour, slightly vinegary smell that catches in the nose.

These descriptions come from the French-language Wikipedia article on silk, which details how to identify fibers by burning them.

3. Weigh it, if a momme is stated

Momme is a unit of weight: 1 momme equals 4.34 g/m², so 22 momme is 95 g/m². A stated momme can be checked on a kitchen scale, on a simple piece whose surface you know, a pillowcase or a scarf, allowing for the seams. Momme does not tell you everything about a silk's quality (here is what momme actually measures), but a figure you can check beats a promise.

What proves nothing

• The OEKO-TEX label. Its STANDARD 100 certifies that a textile has been tested for more than 1,000 harmful substances. It says nothing about fiber content: polyester can be certified.
• The price. A mask or a pillowcase contains little silk: a low price is not enough to give away a fake, and a high price does not guarantee the real thing.
• The feel. A well-finished polyester satin is smooth and cool under the fingers. Touch points you in a direction; it does not decide.

Ice silk or real silk: what changes for sleep?

This is not a moral question. A cool synthetic can feel pleasant on a hot night, and it costs little. The difference lies elsewhere.

How long it lasts. Ice silk's chill is a contact chill: a few seconds, according to Testex. A night lasts hours.

Moisture. Silk has a moisture regain of about 11%: it takes up part of what your skin gives off at night. Polyester, at 0.4%, barely does.

Glide. For friction against skin and hair alone, a smooth synthetic does much of what silk does, for far less money. If that is all you are after, it is a fair choice.

What you pay for. Silk costs more because the fiber costs more. That is only worth it if it really is silk. Hence the one rule that matters: read the fiber content before you buy.

Ice silk sleep masks

A sleep mask is where this matters most: it sits on your eyelids all night, and two of the eight ice silk listings we checked included a mask. One declared polyester and nylon, the other no fiber at all. Before you buy a "silk" sleep mask, check three things: the fiber content of each side, the momme if one is stated, and what actually touches your skin.

Ours fits in one line: both sides are 100% 22 momme mulberry silk, and it says so on the product page. It comes with a mulberry silk pouch. See the Noctya silk sleep mask. To compare it with others, here is our comparison of eleven silk sleep masks, and what Amazon reviews say about fourteen sleep masks.

Already own real silk? Here is how to wash it without damaging it.

Frequently asked questions

What is ice silk fabric?

A trade name, not a fiber: a thin, smooth fabric that feels cool to the touch, sold as "cooling" or "breathable". Depending on the label, it is rayon (viscose), polyester or nylon, often blended with spandex. You find it on underwear, summer blankets, cooling mats and sleep masks.

Is ice silk real silk?

No. It is a trade name for fabrics that feel cool. Mills describe it as rayon (viscose), often blended with polyester, nylon or spandex; on the Amazon France listings we checked, the declared fiber was polyester or polyamide. Only the fiber content tells you the material.

Is ice silk polyester?

Often. Seven of the eight listings we checked declared polyester or polyamide (nylon). Chinese textile firms Yutai and Starketex describe it mainly as rayon. The label decides, product by product.

What does "ice silk" mean?

The word describes a cool feel, which listings push with words like "cooling" or "breathable". It does not name any fiber.

Does ice silk stay cool all night?

No. Testex, a maker of textile testing equipment, writes that the cool-to-the-touch feeling "lasts up to 3-5 seconds", and that polyester breathes poorly, so polyester ice silk sheets can end up feeling hot.

Is an ice silk sleep mask a silk mask?

No, unless its fiber content says "silk". Of the two ice silk masks we checked, one declared polyester and nylon, the other named no fiber at all.

Are satin and silk the same thing?

No. Satin is a weave, silk is a fiber. Silk satin is silk; a product described as "satin" can also be polyester or viscose. Only the composition tells you.

Does the burn test damage the garment?

No, as long as you burn a single thread taken from an inside seam or an offcut, never the visible fabric. Do it over a sink, holding the thread with tweezers.

Does an OEKO-TEX label prove it is silk?

No. OEKO-TEX's STANDARD 100 certifies that the textile has been tested for harmful substances. It says nothing about its fiber content.