Do weighted blankets really work?

Can’t sleep at night?

Whether anxiety is keeping you up or you just aren’t able to log the deep, restful sleep you crave, weighted blankets are increasingly being touted as the answer. These blankets—which often look like regular comforters but are filled with glass or plastic beads or pellets—can weigh anywhere from three to 30 pounds. Some claim that the feeling of using one is akin to a warm hug or a massage.

Before you run out to buy one, though, realize that it may not be a panacea for all that’s keeping you awake.

Here’s what research shows—and what to know—about these blankets.

Why they’re touted to work

Weighted blankets have been used for many years to calm people with anxiety, autism and attention problems.

Ever swaddle a newborn baby? It’s a little bit of the same concept.

This type of pressure is called deep touch pressure, and when it’s evenly distributed to your body’s touch receptors, it’s believed to help you switch from a heightened “fight or flight” stress response to a “rest and digest” mode.

Deep touch pressure is also thought to increase levels of two hormones in the brain— serotonin and oxytocin—that are associated with calm. Serotonin helps produce melatonin, the hormone that makes us sleepy. Oxytocin decreases blood pressure and heart rate. Both may also help boost mood, promoting an overall state of well-being that in turn may be more conducive to a good night’s sleep. The theory, at least, is that sleeping with a weighted blanket has these same effects.

A small 2015 study published in the journal Sleep Medicine and Disorders found that people who used a weighted blanket for two weeks slept longer and reported better sleep quality—and less movement during sleep—than when they didn’t use the blanket. A 2008 study published in Occupational Therapy in Mental Health found that after 32 adults tried a 30 pound blanket, 63% reported that it reduced anxiety and 78% felt it helped them calm down.

A 2014 study published in Pediatrics that looked at 67 children with autism spectrum disorder, meanwhile, found that a weighted blanket offered no objective sleep benefit compared to a normal weight blanket—the kids didn’t fall asleep faster or sleep longer. But the authors did report subjective benefits: The children in the study were more likely to prefer the weighted blanket and their parents were more likely to describe their child’s sleep as better and their behavior as calmer when using the weighted blanket.

Overall, the few studies, like these, that have been done on weighted blankets have been small and limited in various ways. And it’s important to remember that most of the supposed benefits have been based on users’ personal experience.

Who is—and isn’t—a candidate?

It is reasonable to try a weighted blanket if you are experiencing insomnia, or looking for another way to improve your sleep. Just remember that there are other, more research-backed treatments for insomnia available.

Other strategies, such as adhering to a consistent sleep and wake schedule, avoiding blue light from electronic devices for a couple hours before bed, and limiting alcohol and caffeine, especially close to bedtime, could also help.

People with restless leg syndrome (RLS) may benefit from using a weighted blanket. This is because the sensation of the blanket on your legs may override that restless leg feeling.

Bear in mind that there are certain people who should avoid weighted blankets. The blankets are not appropriate for very small children, ages 2 or younger, or the frail elderly. Older adults and parents of children should check with their doctor or occupational therapist before trying a weighted blanket.

How to shop for—and use—a weighted blanket

If you plan to give a weighted blanket a try, as a general guideline, pick one that’s about 10% of your body weight. (So, if you weigh 150 pounds, look for one that’s 15 pounds.)

It’s important to lie it flat across your bed, so the weight is evenly distributed. If you tend to get hot at night or live in a warmer area, opt for a blanket made of cotton, which is more breathable than polyester. There are no published trials comparing one type of weighted blanket to one another, so you may have to do some trial and error before finding one that you like.

Keep in mind that some blankets can be expensive (costing upwards of hundreds of dollars) and they aren’t usually covered by insurance.

This content originally appeared on Sharecare.com