The Best Silk Pillowcases

Momme is the spec that matters, and Grade 6A is a decoy

There is one number that tells you whether a silk pillowcase is worth buying, and most listings do their best to bury it under words that sound more impressive. That number is momme, usually written "mm" and pronounced "mummy." It's the weight of the silk, measured by weighing a fixed-size piece of the fabric — and because heavier silk is denser silk, momme is a direct read on how substantial and how durable the case will be. It is, in effect, silk's version of thread count, except it's far harder to game than the thread-count games we pull apart in our thread count guide.

The ranges are simple enough to remember in the aisle. Below about 19 momme, silk gets thin — more see-through, more fragile, and quicker to wear out. From 19 to 22 mommeis the sweet spot: heavy enough to feel like real silk and last through years of gentle washing, without paying for weight you won't notice. 25 momme — the Fishers Finery on this page — is the premium tier: thicker, more opaque, more durable, and a genuine step up in substance if that's what you want. Push much past that and you're paying for a bigger number rather than a better night. So the honest rule is: buy 19 to 22 momme unless you specifically want the thickest, longest-lasting case, in which case buy 25.

Now the decoy. Look at almost any silk pillowcase on Amazon and it will announce "Grade 6A" silk, printed as though it were a distinguishing feature. It isn't. Grade 6A is a top grade for the raw silk thread, and the problem is that nearly every listing in the category claims it — the ZIMASILK, the Blissy, the ALASKA BEAR, all of them. A spec that every product claims cannot separate one product from another. Treat Grade 6A as table stakes, the price of entry, and nothing more. A case can be Grade 6A and still be a thin 16-momme sheet of silk; the grade tells you about the thread, the momme tells you how much of it you're getting. When a listing shouts about Grade 6A but never states a momme weight — as a couple of the picks above don't — that silence is itself a piece of information, and you should read it as a mild caution.

Silk or satin: the most expensive word in bedding

The single biggest way people overpay — or underpay and get something they didn't want — comes down to two words that get used as if they mean the same thing. They don't. Silk is a fiber. It's a natural protein filament spun by silkworms, and 100% mulberry silk — the standard worth buying — comes from silkworms fed only on mulberry leaves, which produces the finest, most uniform thread. Satin is a weave, a way of crossing threads to float them over one another and produce a shiny, slippery surface. You can weave satin out of almost anything, and when a product is sold as a "satin pillowcase," it is almost always polyester woven in that pattern.

A polyester satin case looks like silk at a glance and costs a small fraction of the price, and if a slick surface is genuinely all you're after, that's a legitimate thing to buy. But be clear that it is not silk and doesn't behave like it. Polyester repels moisture rather than breathing, so a satin case tends to sleep warmer and clammier against your skin — the opposite of what you want if you run hot, which is a whole conversation we have on our cooling sheets page. It also lacks the natural fiber structure that gives silk its hand-feel and its gentleness.

The traps are in the wording. Listings lean on phrases like "silky satin," "satin silk," "silk touch," or "silk-like," all of which are engineered to make you read the word silk and stop reading. Don't stop — go find the fiber content. If it says 100% mulberry silk, it's silk. If it says polyester, microfiber, or simply "satin" with no fiber named, and the price looks too good, it's satin. This is the same regenerated-versus- real problem that dogs bamboo, where a smooth cellulose fabric gets sold on the reputation of the plant it started as; we walk through that one in our bamboo sheets roundup. The FTC has a long history of pursuing bedding sellers over exactly this kind of fiber sleight-of-hand, which is why the honest listings name their fiber plainly.

What a silk pillowcase actually does — and what it doesn't

Here's the part the category's marketing oversells, so let's be precise about it. Silk's benefits are real, and they come from one property: the surface is smooth and low-friction. Your hair and skin slide across it through the night instead of catching and dragging. Because they slide, there's less of the overnight tugging on hair that a rougher cotton weave causes, and less of the bunching that presses creases and sleep lines into your face. Silk also doesn't drink up your skin's natural oils and any night-time skincare the way an absorbent cotton case does — which cuts both ways, but many people count it as a plus. And because silk is smooth and breathes, it tends to feel cooler and less clammy than a warm cotton case, without the plastic hand of a polyester satin.

The honest limit is the size of the effect. These benefits are modest and gradual, not miraculous. A silk pillowcase is a gentle upgrade, not a treatment: it will not stop hair loss, it will not erase wrinkles, and it will not clear up acne, whatever a product photo with a before-and-after implies. The friction reduction is genuine and the reduced creasing is genuine, but they're small, and if you go in expecting a transformation you'll feel cheated by a product that is actually doing exactly what silk does. It's also worth remembering that the case is the layer on top; the pillow underneath it does far more for how you actually sleep, which is why we'd point you at our best pillows guidebefore you spend heavily on the cover for a pillow that's wrong for you.

And here is what we can't tell you, because we'd be making it up if we did. We have not run a friction test on these cases. There is no test lab behind this site, we don't own the equipment to measure a coefficient of friction, and anyone handing you a precise number for how much less your hair breaks on a specific Amazon pillowcase is inventing it. What we can do honestly is reason from the material: silk fibers are physically smoother than cotton fibers, a smoother surface produces less friction, and less friction means less tugging and creasing. That's textile physics you can rely on — it is not a measurement we took, and we won't dress it up as one.

The care tax, and the specs that cause the returns

Silk is delicate, and owning it is an ongoing commitment rather than a one-time purchase — so factor the care in before you buy. The safe routine is a hand wash in cool water with a detergent made for silk or a pH-neutral one, or, if you must use a machine, the case zipped into a mesh laundry bag on the most delicate cold cycle. Skip bleach entirely, and avoid ordinary enzyme or "biological" detergents: the same enzymes that break down food stains also digest protein fibers like silk. Then air dry, flat or on a line out of direct sunlight, and keep it out of the tumble dryer, which is where most silk cases meet their end. Next to throwing a cotton case in on hot with the towels, that's a real chore, and it's a fair part of what you're signing up for.

Two specs cause most of the disappointment, and both are easy to check. The first is size. Silk cases are cut close, with little give, so a standard-size case on a queen or king pillow is a struggle to get on and looks strained once it's there — the ALASKA BEAR above is a standard-size listing, so read that one carefully against the pillow you actually own. The second is the closure. A hidden zipper, which the Blissy, BYTB, and LilySilk picks state, keeps the case on a firm pillow all night; the envelope-fold closures on cheaper cases gape and let the pillow creep out. Neither spec is glamorous, and both are the difference between a case you love and a case you return.

Finally, price honesty. Real mulberry silk is genuinely expensive per case, and there's no way around that without stepping off silk entirely. The two levers that lower the cost are buying a two-pack — the BYTB gets you two 22-momme cases for less per case, and you need a spare for wash days anyway — or buying at the entry momme, like the 19-momme LilySilk. But be honest with yourself about what you want. If the silk-specific gentleness on your hair matters to you, buy silk. If what you're really after is a surface that's smooth and sleeps cool, and the price of silk is the sticking point, a good bamboo viscose or a well-chosen cooling set gives you slippery-and-cool for a lot less — our best sheets on Amazon roundup covers those options. The pillowcase is a small, pleasant lever; don't let the marketing convince you it's a big one.