Search for a silk pillowcase online and you'll find hundreds of listings under £20. Here's the uncomfortable truth: most of them aren't silk at all. They're polyester satin, photographed beautifully, described with words like "silky" and "luxurious", and sold to people who have no easy way of checking. If you've ever wondered how to tell if silk is real, you're asking exactly the right question — and the good news is you don't need a laboratory to answer it. A few simple tests, some done in seconds, will expose most fakes.
Below are seven tests, roughly in order of convenience. The first four you can do in a shop or with a delivery in your hands. The last three take a little more effort but are close to conclusive.
How to Tell if Silk Is Real: Tests You Can Do in Seconds
1. The touch and warmth test
Real silk is a natural protein fibre, and it behaves like one. Press it against your cheek or hold it between your palms for ten seconds. Genuine silk warms to your skin almost immediately — it takes on your body temperature the way wool or hair does. Polyester satin stays cool and slick no matter how long you hold it. It feels smooth, yes, but it's a slippery, almost plasticky smoothness, and it never quite feels alive.
Rub silk gently against itself and you may also hear a soft, dry rustle — sometimes called "scroop". Synthetics tend to be silent or squeaky.
2. The lustre test
Hold the fabric up to a window and tilt it. Real silk has a layered, almost pearlescent shimmer: the colour appears to shift as the angle changes, because silk's triangular fibre structure refracts light like a prism. A white silk pillowcase might flash faintly ivory, then silver, then warm.
Polyester satin shines too — but it's a flat, uniform, white-ish sheen that looks the same from every angle. Once you've seen the two side by side, you'll never confuse them again. (Satin, remember, is a weave, not a fibre — anything from silk to polyester can be woven as satin. We've written a full breakdown in our guide to the difference between silk and satin pillowcases.)
3. The ring test
An old silk merchant's trick: pull the fabric through a plain ring. Fine silk is so smooth and supple that it glides through in one motion, while most synthetics bunch, snag or squeak.
An honest caveat, though. This test works well for scarves and other lightweight silks. For a hemmed, double-sided pillowcase with a zip, it's far less useful — the construction gets in the way long before the fibre does. Use it where it makes sense, and don't read too much into it elsewhere.
4. The price sense-check
This one requires no fabric at all, just arithmetic. Mulberry silk is expensive to produce: silkworms must be raised on mulberry leaves, and it takes thousands of cocoons to make a single pillowcase. Raw silk trades as a genuine commodity with a real floor price.
So when a listing offers a "100% mulberry silk" queen pillowcase for £12, something has to give. Either it isn't silk, or it's a whisper-thin fabric far below a usable weight. A properly made 22 momme pillowcase simply cannot be produced, shipped and sold at that price. As a rough guide, genuine 22 momme pillowcases in the UK tend to sit between £45 and £110. If a price looks too good to be true, it very reliably is. (If "momme" is new to you, our guide to momme silk weight explains it in plain English.)
The More Thorough Tests
5. The burn test
The classic. Take a single loose thread — from an inside seam, never the fabric itself — hold it with tweezers over a sink or plate, and touch a flame to the end.
- Real silk burns slowly, smells distinctly of burnt hair (it's protein, chemically similar), self-extinguishes when you remove the flame, and leaves a brittle, crushable black ash.
- Polyester smells of burning plastic, melts rather than burns, keeps going once lit, and hardens into a small dark bead you can't crush.
Two obvious limitations. First, safety: one thread, tweezers, a sink nearby, nothing flammable around. Second, you clearly can't do this before buying — it's a test for something already in your hands, ideally within a returns window.
6. The label check
A trustworthy silk seller will tell you three things without being asked:
- The fibre: it should say "100% mulberry silk" — not "satin", "silky fabric" or just "silk-feel".
- The momme weight: a number, typically 19–25 for pillowcases. If no momme is stated anywhere, treat that as a red flag; sellers of real silk know buyers ask.
- The grade: mulberry silk is graded from A to C, with 6A the highest long-fibre grade. Not every honest seller states a grade, but the good ones tend to.
Vagueness is the tell. Fake silk listings are wordy about softness and sleep benefits, and strangely silent about fibre content.
7. The certification check
OEKO-TEX® Standard 100 certification means the finished textile has been independently tested for harmful substances. It isn't a silk-purity certificate as such — but it does mean a real company submitted a real product to a real laboratory, which fly-by-night polyester sellers rarely bother with.
Better still, you can verify it yourself. A genuine OEKO-TEX® certificate has a number, and you can enter that number on the official OEKO-TEX® Label Check website to confirm it's valid and matches the product type. If a seller claims certification but won't show a certificate number, assume there isn't one.
Quick Reference: Real Silk vs Fake at a Glance
| Test | Real silk | Fake (polyester satin) |
|---|---|---|
| Touch & warmth | Warms to skin within seconds | Stays cool and slick |
| Lustre | Shimmers, colour shifts with angle | Flat, uniform white sheen |
| Ring test | Glides through smoothly (scarves) | Bunches, snags or squeaks |
| Price | Reflects a real commodity cost | Suspiciously cheap (£10–20) |
| Burn test (one thread) | Burnt-hair smell, self-extinguishes, brittle ash | Plastic smell, melts into a hard bead |
| Label | States "100% mulberry silk", momme, often grade | Says "satin", "silky" or nothing specific |
| Certification | Verifiable OEKO-TEX® certificate number | No certificate, or one that can't be checked |
The Tricks Sellers Use to Sell Fake Silk
Most fake silk isn't sold with an outright lie. It's sold with careful wording that lets you assume the lie yourself. Watch for:
- "Satin pillowcase" positioned next to silk imagery. Legally accurate — satin is a weave — but designed to make you read "silk". If the word "satin" appears without a fibre named, it's almost always polyester.
- "Silky", "silk-feel", "silk-like". None of these mean silk. All of them mean not-silk, or the listing would just say silk.
- Stock photography. The same handful of glossy fabric images circulate across dozens of listings. If a seller has no photos of their actual product — creases, seams, packaging — be wary.
- Momme inflation. Some listings claim "25 momme" or even "30 momme" at a 19-momme price. Momme is rarely tested by buyers, so it gets exaggerated. Weight is one honest check: a genuine 22 momme queen pillowcase has a noticeable heft that thin fabric can't fake.
Already Bought Fake Silk? Here's What to Do
First, don't be embarrassed — these listings are built to deceive. Then act while you can:
- Request a return. If the item was described as silk and isn't, that's a misdescription. Under the Consumer Rights Act 2015, goods must match their description, so you're entitled to a refund — and distance-selling rules give you at least 14 days to change your mind on most online purchases anyway.
- Keep the evidence. Screenshot the listing before it changes, and note any burn-test or label findings.
- Report it. Misdescribing polyester as silk is a matter for Trading Standards — report via the Citizens Advice consumer service, which passes cases on. Marketplace platforms also accept counterfeit and misdescription reports against individual sellers.
Frequently Asked Questions
Is satin the same as silk?
No. Satin is a weave — a way of constructing fabric — while silk is a fibre. You can weave silk into satin, but nearly all budget "satin" bedding is woven from polyester. If a label says satin and never names a fibre, it's synthetic.
Can silk really be machine washed, and does that prove it's real?
Good-quality silk can be machine washed on a cold, delicate cycle in a mesh bag, so washability proves nothing either way. Ironically, polyester survives careless washing better than silk does — durability under abuse is not a sign of authenticity.
What momme weight should a real silk pillowcase be?
For pillowcases, 19 momme is a sensible minimum and 22 momme is the sweet spot — dense enough to be durable and opaque without the price jumping sharply. Anything sold without a stated momme weight deserves scepticism.
Does a high price guarantee real silk?
Unfortunately not. A £12 price almost guarantees fake, but a £70 price guarantees nothing — some sellers simply charge silk prices for polyester. Price rules fakes in; it never rules them out. Check the label, the momme, and the certificate regardless of cost.
Check Ours However You Like
We'd rather be tested than trusted blindly. Lunare Home pillowcases are 22 momme, Grade 6A mulberry silk, made from OEKO-TEX® Standard 100 certified silk, at £50.99 — and we publish those numbers because they're the ones a careful buyer should be asking about. Our 30-Night Sleep Trial exists for exactly the reasons in this article: warmth test it, tilt it in the light, weigh it in your hands, and if it doesn't behave like real silk, send it back. Delivery is free across the UK on orders over £40. Every test above, we invite.
