A woman resting on a pillow with the right pillow fill.

In the universe of bed pillows, firmness is just one of the factors. The type of material, called fill, can have a big affect on your comfort.

There are pillow fills that claim to cool you down, fills meant to contour to your cranium, and even fills that are said to keep bacteria at bay. Consumer Reports doesn't test pillows, but we asked two pillow professionals to explain the upsides and downsides of each type of fill.

Down Pillows

Feathers and down aren't one and the same. Down refers specifically to the soft clusters under the breast feathers of geese and ducks that insulate the birds in cold weather. It’s warmer than feathers and doesn’t have quills, so they won’t poke through pillows and jab you. Keep in mind, though, that almost all down pillows contain a certain percentage of feathers to increase volume.

Pros: “Aside from being incredibly soft, the nice thing about real down is that it’s anti-microbial and hypoallergenic,” says James Maas, CEO of a sleep-research firm called Sleep for Success and a former professor and chairman of the psychology deopartment at Cornell University. "A lot of people think they’re allergic to down, but what they’re probably allergic to is dust mites.” If you use a pillow protector—a tightly woven cloth sack that the pillow goes into before the pillow case—you can most likely sleep on down without a problem, according to Maas.

More on Sleep

Cons: Down is pricey. “You need a lot of it to support your head,” explains Maas. So a pillow that’s 100 percent down is going to set you back. And those with feathers mixed in may have quills poking through. Also, you’re going to be doing a lot of fluffing; that’s a constant requirement with down pillows. And eventually, down goes permanently flat. One last thing: Some down has a bit of a natural odor, a subtle, gamy smell you might not like.  

Good to know: If you’re shopping online and don’t have the opportunity to feel down pillows you’re considering, you can look at the “fill power” to get a sense of fluffiness. The figure (typically 300 to 800) refers to the space occupied by an ounce of down. The higher, the better.


Natural Latex

Think of latex as a chemical-free foam. It’s produced from the milk of the rubber tree, and in the pillow world you’ll hear about two varieties: Dunlop, which is denser at the bottom than the top, and Talalay, more consistent in terms of texture—and more costly.

Pros: Many chiropractors prescribe latex pillows for neck or back pain. “Latex is buoyant and bouncy,” says Sam Malouf, CEO of the luxury bedding company Malouf, which makes pillows. “It pushes back so your head feels suspended, as if it’s floating.” If you’re a warm sleeper, you should find latex comfortable; the material is porous and disperses heat. “It’s also anti-microbial and mildew-proof,” adds Maas.

Cons: Latex pillows are expensive, and they can have a rubbery smell at first, so you'll want to air them out a bit. Also, some people are allergic to latex.

Good to know: If you sleep especially hot, look for latex pillows infused with copper. “Copper is like a highway, distributing heat throughout the pillow to leave you cooler,” says Malouf.


Memory Foam

Also known as visco-elastic foam, this petroleum-based high-density polyurethane foam was invented in the late 1960s by NASA to make airplane chairs comfortable and safe during takeoff. It’s supposed to evenly distribute weight—which explains its popularity as a mattress material—and respond to heat and pressure.

Pros: Memory foam feels cushy. It contours to the shape of your head and slowly returns to form. You can find options in different densities based on your preference. “Some versions are soft as a marshmallow and others take time to sink into,” explains Malouf. Since it’s hypoallergenic and anti-microbial, memory foam is low-maintenance and needs only occasional spot-cleaning. And unlike a down pillow, a memory foam pillow shouldn't go flat over time.

Cons: Memory foam absorbs heat, which isn’t great for sweaty sleepers. And the texture is not for everyone. “Even a soft version may be firmer than what you expect,” Malouf says. Also, the firmness of a pillow can change. Because it responds to heat, Malouf says, “memory foam can get softer in summer months and harder in winter.” Last but not least, memory foam can emit volatile organic compounds, and the smell may take a few weeks to dissipate. You'll definitely want to air out your memory foam pillows before use. 

Good to know: For extra fluff, look for memory foam wrapped in down. It’s hard to determine how a memory foam pillow will suit you without sleeping on it, but when you’re shopping, you can get a sense of relative firmness by weight. A heavier pillow is likely to be firmer.


Gel

The gel used for pillows is generally polyurethane encased in plastic. Manufacturers layer this on top of a more traditional pillow material, like memory foam. Sometimes manufacturers shred or chop gel and blend it right into memory foam.

Pros: “Gel has marvelous cooling properties that can help you fall asleep,” says Maas, who notes that a drop in temperature is beneficial at bedtime. “If you take a hot shower, then lay your head down on a gel pillow, your temperature will plummet. This rapid change helps you drift off.”

Cons: It’s a temporary situation. “Gel absorbs heat but can’t dissipate it,” says Malouf, “so the coolness typically wears off in 10 minutes.”

Good to know: If you're committed to your current pillow but want to try the cooling effects of gel, consider a gel mat. You can put it in the refrigerator, then slip it inside your pillowcase before bed.


Polyester

Polyester is a super-strong synthetic fiber made from petroleum. It can be processed and used many different ways, so you’ll find polyester pillows of various quality, comfort level, and price. “Down alternative” is one of many polyester code names.

Pros: You can throw polyester pillows in the washing machine and dry them on low in a dryer. And there are really comfortable fluffy, well-made poly pillows, often in the aforementioned “down alternative” category. Some even feature luxurious details like gusseting and cotton sateen covers.

Cons: The texture of poly provides lots of places for dust mites to hide. And polyester can sometimes be uncomfortable. “My issue with polyester is the unnatural feel of it,” says Maas. Some poly pillows have a short life span; they can get flat and lumpy in months. Maas warns against super-inexpensive options: “Very few of them will be truly supportive."

Good to know: Many pillows marketed as “hypoallergenic” are made of polyester, but this is a specious claim. It just means that people aren’t allergic to polyester.


Wool

Wool pillows are, as you would imagine, stuffed with fine fibers from the fleece of sheep and goats, and sometimes other hairy mammals, like alpacas. It’s easy to find manufacturers who use only unprocessed wool and organic cotton covers, an option for those looking for a truly chemical-free bedfellow.

Pros: Wool pillows have a rustic appeal (some are hand-stuffed). People tend to associate wool with warmth, but, Malouf points out, “the reason wool is used for things like military uniforms is that it’s a great insulator—against both heat and cold.” Wool pillows keep you warm in winter and cool in summer. Wool is good at wicking away moisture so mold and mildew can’t thrive.

Cons: Wool pillows can feel a bit dense and flat. “Most don’t conform to your head,” says Maas. “You’ll have to move around a lot to get comfortable.”

Good to know: Some wool pillows have a zipped side, so you can remove some of the filling for less loft and add the fill back in when the wool settles. If you like the idea of wool but want more cush, consider a natural latex pillow wrapped in wool.