Slip is a real silk pillowcase: Slip states it uses Grade 6A long fiber, 100% mulberry silk at 22 momme, and a queen is $120 in most colors. Whether it's worth it comes down to what you want to verify. Slip publishes its specs and a third-party friction test, but I couldn't find a certificate number on its FAQ or pillowcase pages.
I'm Erin Wise, founder of Wink Silk. I sell a pillowcase that costs more than Slip, and I have no relationship with them. Everything I say about Slip comes from its own website, checked on October 30, 2026. Pages change, so check their product page before you decide.
What is Slipsilk made of?
Slip calls its fabric Slipsilk™. In Slip's words: "We use the highest grade (6A) long fiber 100% pure mulberry silk, with a thickness of 22 momme." Slip also writes, "We guarantee our measurement of 22 momme."
That's a clear spec. Momme, grade and fiber, all in writing. Plenty of brands won't give you all three.
What does Slip's "43% less friction" claim mean?
Slip says Slipsilk™ was tested by an independent third-party lab and shown to create 43% less friction on average, compared with widely available cotton pillowcases of 220 to 360 thread count.
That fits what silk honestly does: it reduces friction against your hair and skin compared with cotton. That's the whole claim, for Slip and for us. The 43% figure is Slip's own result, so read it as the brand's claim. If you have a skin or hair condition, talk to your dermatologist.
Can you verify Slip's silk yourself?
Partly. You can't hold a grade up to the light. Grade was one of the words I kept seeing and couldn't check. A certificate number is different. You type it into a public database and get an answer.
Slip's FAQ mentions independent lab testing. I didn't find an OEKO-TEX certificate number on its FAQ or its queen pillowcase pages. That doesn't tell you anything is wrong with the silk. It means I can't hand you a number to look up. If that matters to you, ask Slip for one.
Is a Slip pillowcase worth $120?
Here's what the $120 buys, next to Wink. The per-night figures spread each price over the same two years, for comparison only, not a promise of how long anything lasts.
| Slip | Wink Douceur™ | Wink Douceur Doublure™ | |
|---|---|---|---|
| Momme | 22 | 25 | 25, two layers |
| Grade and fiber | 6A long fiber, 100% mulberry | Grade 6A, 100% mulberry, charmeuse | Grade 6A, 100% mulberry, charmeuse |
| Certificate number published | None found on pages checked | OEKO-TEX 22.HCN.30712 (Class I) and GOTS license 00284622, held by our silk house | |
| Queen price | $120 most colors | $185 | $245 |
| Per night over two years | about 16 cents | about 25 cents | about 34 cents |
Slip has two things going for it in this table: a lower price, and a choice of envelope or zipper. When I checked, a few Slip colors were also on sale. Blissy and Quince list the same 22 momme weight, so if you're weighing Slip against them, the silk weight won't separate them. Price, closure and paperwork will.
How does Wink Silk differ from Slip?
Wink makes Performance Luxury Silk™: 25 momme, Grade 6A, 100% mulberry silk charmeuse, crafted by a GOTS & OEKO-TEX certified silk house. 25 momme carries about 14% more silk per square meter than 22, so there's more fiber to wear through. Here's what changes between 22 and 25 momme.
Wink Silk itself is pursuing its own GOTS and OEKO-TEX certifications. We don't hold them yet. What we can show you today are our silk house's numbers, and you can check both in a few minutes. Here's GOTS vs OEKO-TEX, explained.
Our prices are permanent, and we don't run sales. The Douceur Doublure™ founding edition is 330 hand-numbered pieces in Coy™, never restocked. For Slip next to Blissy, see Blissy vs Slip vs Wink Silk. Looking for something like Slip for less? That's how to judge a Slip dupe.
What should I check before buying any silk pillowcase?
- Momme, in writing. 22 or higher.
- Fiber named as 100% mulberry silk, not just "satin."
- A certificate number you can enter at OEKO-TEX Label Check.
Three checks, five minutes. Use them on Slip, and use them on us.
Wink Privé, our free membership, opens November 2, three days before everyone else, so if you want to be there first, join at winksilk.com/pages/founding.
Wink. The brand that shows you the certificates.
Sleep beautifully.
Sources
- FAQ (Slip)
- Queen zippered pillowcases (Slip)
- Queen envelope pillowcases (Slip)
- OEKO-TEX Label Check
- GOTS Certified Suppliers Database
25 momme mulberry charmeuse with two certificate numbers you can look up tonight.
Frequently Asked Questions
Is Slip a real silk pillowcase?
Yes. Slip states Slipsilk is Grade 6A long fiber, 100% pure mulberry silk at 22 momme, and says it guarantees the 22 momme measurement. Queen pillowcases were $120 in most colors on Slip's site on October 30, 2026.
What is Slipsilk?
Slipsilk is Slip's name for its fabric. Slip describes it as specially commissioned 100% pure mulberry silk, Grade 6A long fiber, 22 momme.
Does Slip have an OEKO-TEX certificate?
Slip's FAQ says Slipsilk was tested by an independent third-party lab. No OEKO-TEX certificate number appeared on its FAQ or queen pillowcase pages when checked on October 30, 2026. If a certificate matters to you, ask Slip for a number you can enter at OEKO-TEX Label Check.
Does Slip come with a zipper or envelope?
Both. Slip sells queen pillowcases with an invisible zipper and with an envelope closure.
How does Slip compare with Wink Silk?
Slip is 22 momme at $120. Wink is 25 momme, $185 single layer or $245 double layer, crafted by a GOTS and OEKO-TEX certified silk house with public certificate numbers. Over two years, that's about 16 cents a night for Slip and 25 to 34 cents for Wink.
