Celebrities use them. Instagrammers love them. Hair stylists recommend them. Silk pillowcases are not new, but over the past couple of years, they seem to have exploded in popularity, embraced by the beauty and wellness industries and credited with delivering smooth, shiny hair and wrinkle-free, supple skin.
That doesn’t mean you have to rush out to buy one. Although acknowledging that silk pillowcases may provide some benefits for hair and skin, doctors say the products are best seen as a supplement to existing routines or as a self-care indulgence.
Amy Fox, a board-certified dermatologist and associate professor specializing in hair loss at the University of North Carolina at Chapel Hill’s School of Medicine, says that because so little research has been done on silk pillowcases, much of the information about them is anecdotal.
But there’s also no danger in trying one, says Pooja Sodha, a board-certified dermatologist and director of the George Washington Center for Laser and Cosmetic Dermatology in Washington — other than the hit to your pocketbook, because some brands can be pricey. “There’s no harm in silk pillowcases, and there may be a benefit, but it’s not the first step that we’d take for treatment,” she says.
Silk has been used for thousands of years in a variety of applications. It’s the only naturally occurring filament fiber, which means its threads are continuous and don’t need to be stitched together. Fibers that have to be spun together to form threads, such as cotton or linen, have rougher textures, because they contain more “corners,” but they can be blended and treated to be softer.
Silk also regulates temperature well and doesn’t absorb much moisture, Gopinath says; these properties are the main reasons for its supposed beauty benefits.
What silk does — and doesn’t do — for hair
The benefits of a silk pillowcase are most pronounced for hair, experts say, because the silk can help hair retain moisture from products and natural oils and reduce friction that could cause tangles and breakage. It’s especially beneficial for curly or natural hair, which doesn’t retain as much moisture as straight hair and is more prone to breakage, says Misty Eleryan, a micrographic surgery and dermatologic oncology fellow at the Ronald Reagan UCLA Medical Center. “It’s all a domino effect: If the silk or satin doesn’t absorb that moisture, then your hair stays moisturized and your hair isn’t as prone to breakage.”
Eleryan says people with straighter or smoother textures could still benefit from reduced friction, but silk scarves or pillowcases aren’t essential for their hair care.
Carmen Powers, a color specialist at Spoke & Weal’s Flatiron location in New York, recommends silk pillowcases to her clients who color their hair, regardless of texture. Heat styling, chemical treatments, color and rough handling can also weaken strands and create split ends and dryness, which could lead to breakage. To avoid breakage, she recommends gentle handling and styling, regular trims to prevent split ends and products such as heat protectors.
But although a silk pillowcase may prevent breakage, it won’t prevent hair loss.
We all shed hair throughout the day. More significant hair loss can be caused by a number of factors — alopecia, chemotherapy, hereditary baldness, childbirth, stress — but your pillowcase doesn’t have anything to do with it. “Whether it’s cotton or silk, the pillowcase you sleep on at night doesn’t influence your hair loss in any way,” Fox says. Outside of medical or hereditary causes, “the things we do that create hair loss are the things we do mechanically to our hair,” including heat styling and rough handling. A pillowcase won’t prevent that.
What silk does — and doesn’t do — for skin
Silk pillowcases’ benefits for skin are murky, experts say. Advertisements say silk’s smooth surface won’t wrinkle or crease the skin, which causes fine lines to form. They say that’s especially beneficial for side and stomach sleepers, whose faces make constant contact with the pillow throughout the night.
But while a smooth sleeping surface could be helpful to prevent sleep creases from becoming deeper, experts say, it probably isn’t a major factor in age-related wrinkles.
Some products claim that because silk contains amino acids, sleeping on a silk pillowcase will transfer them into the skin and hair; doctors say this isn’t true. Some products created to reduce fine lines, heal wounds or coat split ends to protect from further damage contain silk derivatives, but they’re topically applied or injected.
“That’s really pushing it. … Think about how protective your skin is,” says Jenny Kim, a board-certified dermatologist, professor at the UCLA David Geffen School of Medicine and director of UCLA’s cosmetic dermatology division. “How can [lying] on a pillow jump the amino acid from the pillow into your skin? It just doesn’t make sense.”
Some user reviews have said that silk pillowcases helped reduce lesions and lessen inflammations such as acne and dermatitis, and many advertisements tout silk’s antimicrobial and hypoallergenic properties. Mary Stevenson, a board-certified cosmetic dermatologist and assistant professor of dermatology at New York University’s Grossman School of Medicine, says that although this idea is intriguing, it hasn’t been widely studied, and there is very little data to support any benefits.
People concerned with acne, dermatitis and aging are better served looking at other aspects of their routine first before rushing to buy a silk pillowcase, experts say. A lifestyle that includes a healthful diet, exercise, quality sleep and wearing sunscreen of at least 30 SPF daily will also benefit skin and hair. “It’s not a panacea, and it’s not a clear-cut yes or no answer, but it’s something else to add to your toolbox,” Stevenson says. “I would say it’s a very nice indulgence.”
How to buy one
There are numerous pillowcase options available in stores and online at prices ranging from $10 to more than $100. If you want to try one, look for a product made from 100% mulberry silk, says Preeti Arya, a textiles professor at the Fashion Institute of Technology. Less expensive options might be silk blended with a synthetic fiber; silk is commonly blended with polyester and rayon. Satin-weave fabrics will also create a smooth surface. (Ngina Thomas, owner and master stylist at the Studio Chique salon in the District, prefers satin to silk and says brand names don’t matter as much as the texture.)
Many products provide the momme count, a number up to 30 that indicates silk’s weight and density, but Gopinath and Arya say it’s not the best unit for quality, because metals or fillers can be added to artificially increase the number. Look for certification from the Global Organic Textile Standard, which means a product is made of at least 70% natural fibers, and OEKO-TEX, which means the product doesn’t contain chemicals or additives.
“You don’t want something that feels like tissue paper,” Arya says. “If it’s not less than 12 [momme] or more than 24, we’re good, but I would not pay $110 for 22 or 30 momme,” she says. Silk is also graded from A to C based on its luster and thread uniformity; most mulberry silk is grade A and will look significantly smoother than B- or C-grade silk. And those varied prices? For one pillowcase, Arya says she wouldn’t spend more than $40.