The best cooling pillows for side sleepers

Match the cooling feature to when you overheat.

• Hot the moment you lie down. Gel layers and cool-to-touch covers feel cool on contact^[5], but that chill is a first-touch effect that fades as they warm up^[6]. The TEMPUR-Cloud Dual Cooling has gel on both faces, and the Helix ComfortAdjust has a cool-touch cover.
• Hot and damp by the middle of the night. You need an open structure: the Purple Harmony's latex and grid, or the shredded fills in the Nest Easy Breather, Coop Eden and SUPA MODERN.
• Sudden waves of heat and sweat. A breathable pillow helps, but see the night sweats section for what treats hot flashes.
• Hot all over. Start with the bedroom, not the pillow.

Partly. Cool-to-touch covers feel cool when you first lie down, then warm up. Breathable fills keep working all night. A cover or gel layer pulls heat from your skin only while it's cooler than you are. Once it catches up, what matters is whether the fill lets heat and moisture escape. Sleep Foundation's testers put it simply: flipping a pillow to the cool side helps, but only briefly^[5].

The evidence on sleep itself is thin. A 2025 meta-analysis reviewed 9 randomized trials of bedding designed to cool the body, such as mattresses, toppers or pillows, in healthy adults. The trials suggested cooling bedding lowered core body temperature in the short term. But it made no clear difference to how fast people fell asleep, how long they slept, or how much deep and REM sleep they got, and the authors rated the certainty of the evidence very low to low^[7]. Buy a cooling pillow for comfort, and treat bigger promises with caution.

Your body has to shed heat to fall asleep and stay in deep sleep, and a hot bed slows that down. Core temperature starts to fall about two hours before you go to sleep and keeps dropping to a low point in the early morning^[1]. The heat leaves through your skin. Blood vessels in the hands and feet widen, and that shift of heat to the skin helps you fall asleep quickly^[2].

When the bed is too warm, that heat loss stalls. A review of thermal sleep research found that heat exposure increases wakefulness and cuts slow-wave (deep) and REM sleep, even with normal bedding and clothing^[2]. When people sleep well, the air under the covers usually sits at about 90–93°F (32–34°C) and 40–60% relative humidity^[2]. A pillow that traps heat and sweat around your head works against that.

Cooling the head has helped in hot rooms and small lab studies, but the effects are modest and mixed.

• A cooling pillow in humid heat (9 men). At 90°F (32°C) and 80% humidity, the men woke more than in a comfortable 79°F (26°C) room. With a cooling pillow, their wakefulness was no longer significantly higher than in the comfortable room, and they sweated less overall. Their core and skin temperatures still stayed higher than in the comfortable room^[8].
• Local cooling in a 90°F room (16 men). Cooling the head and neck alone slightly improved comfort, rated sleep quality and deep sleep, but nothing else. Cooling the back and head together raised sleep efficiency from 84.6% to 95.3%^[9].
• A water-cooled head sheet (14 young women). Compared with a 95°F (35°C) sheet, a 77°F (25°C) one gave more deep sleep (14.2% vs 10.1% of sleep) and fewer arousals. It didn't change how quickly they fell asleep or their sleep efficiency, and participants knew which sheet they had^[10].
• A forehead device for insomnia (106 adults). A device holding the forehead at 57–61°F (14–16°C) for two nights missed both of its main goals: time to fall asleep and sleep efficiency. Several secondary measures of falling asleep did improve. The device maker helped fund the trial, and one author founded the company^[11].

The clearest benefits came in hot rooms, where a fan or air conditioning would also help. And some of these studies used water-circulating or powered devices that hold a set temperature all night, which a passive pillow can't do. A cooling pillow is a comfort upgrade, not an insomnia treatment.

Every cooling feature does one of two things: it soaks up heat for a while, or it lets heat and moisture escape. The first kind fades. The second lasts all night.

Cool-to-touch covers

These fabrics feel cold because they pull heat from your skin quickly at first contact. Textile labs measure this as q-max, the peak heat flow at the moment of contact. In a study of 40 summer fabrics, that first-touch coolness depended mainly on fabric thickness and how much heat the fabric can absorb for its volume^[6]. The limit is built into the measure: it describes the first touch, not the third hour. The Helix GlacioTex cover and the SUPA MODERN cool side work this way.

Phase-change materials (PCM)

PCMs are compounds, often sealed in microcapsules, that absorb heat as they melt at a set temperature, which gives a temporary cooling effect^[12]. How much heat they hold depends on how much PCM is applied. One review gives the example of a fabric carrying 22.9% microcapsules that absorbs 4.44 joules per gram as they melt. Melting ice absorbs 335 joules per gram^[12]. A thin cover has little capacity to spare. In a test of a PCM mattress, 20 people lay on it and on a regular mattress for 20 minutes each. Skin temperature rose 0.5–1.8°F (0.3–1.0°C) less on the PCM mattress, yet people rated their comfort and warmth the same on both^[13].

Gel layers

Gel, graphite and copper infusions are meant to draw heat away from your body^[5]. How long that lasts depends on heat capacity: how much heat a layer can absorb before it warms up. In 72 adults, a mattress with a dense, high-heat-capacity top layer added an average of 7.5 minutes of deep sleep a night and lowered heart rate by about 2 beats a minute compared with regular memory foam. Results varied a lot between people, and one author worked for the company that made the top layer^[14]. A pillow's gel layer is far smaller and touches only your cheek and ear, so expect its cool to fade. Flipping the TEMPUR-Cloud Dual Cooling to its other gel face restarts it.

Airflow: the feature that lasts

Fill structure decides how fast heat escapes after the first few minutes. Solid foam generally holds more heat than shredded foam, many cooling pillows use aerated latex to move air, and buckwheat hulls leave air pockets between them^[5]. That's why our ranking puts open, springy constructions on top and solid memory foam last. For why foam holds heat, see our memory foam guide.

On your side, more of your face presses into the pillow, and your face is especially sensitive to heat. On your back, mostly the back of your head touches the pillow. On your side, your cheek, ear and jaw sink in, and a high-loft side-sleeper pillow wraps around more of your face. In a lab study of 13 men, the face was the most temperature-sensitive region tested. When warmed, it was 2 to 5 times more sensitive than the arms and legs for triggering sweat, and 2 to 3 times more for overall discomfort^[3].

So a pillow that holds heat against your cheek can make you feel hot all over, even when the room is fine. Contact area matters too. In a Japanese lab evaluation of pillows, those that lost more heat, conducted it better and touched less of the head ran cooler at the head after 30 minutes and were rated cooler^[15]. Latex, shredded fills and grids hold their shape and leave air gaps, which is one reason our cooling picks lean that way.

Feeling hot in bed is often about moisture as much as temperature. Sweat cools you only when it evaporates, and humid air stops it evaporating^[2]. In a lab study of 7 young men sleeping at 95°F (35°C), raising humidity from 50% to 75% significantly cut REM and deep sleep^[16].

A pillow can trap that damp layer against your face. When Hong Kong's Consumer Council tested 13 pillows, the relative humidity measured during use ranged from 48.5% to 66.9%. Two of the 7 memory foam models had comparatively high readings of 59.1% and 66.9% and lost points for moisture permeability. One tester lay on each pillow on their back, so treat it as a rough comparison^[17]. What helps: a fill with air gaps, a case that wicks moisture^[18], and a spare case to swap in if you wake up damp.

Treat a “degrees cooler” number as marketing until you know what was measured, against what, and for how long. Unless the brand publishes its method, you can't tell. The figure might describe the cover surface in the first seconds or a lab plate rather than a person, and even measured differences may not be felt, as the PCM mattress test showed^[13]. Ask these questions instead:

• Is it cool-to-touch, breathable, or both? Cover-only cooling fades. Look for an open fill or grid as well.
• Who did the test? Manufacturers' figures aren't independent. Editorial lab testing and owner comments are better guides.
• Can you return it? A few warm nights tell you more than any spec sheet, so check the return window before you buy.

Choose a breathable case in percale cotton, linen or lyocell. Percale uses a one-over-one-under weave and is often considered the best sheet for hot sleepers. Sateen floats one yarn over three or four, feels heavier and is more likely to trap heat^[19]. Sleep Foundation's testers recommend cotton, linen and bamboo-derived fabrics for hot sleepers, and an expert they quote notes that synthetic fibers tend to be less breathable, so skip polyester satin^[18]. On your side, your face lies on the case all night, so the fabric matters more for you than for a back sleeper. Research on bedding and sleep quality is scarce, though^[20], so this advice rests on fabric physics and tester experience rather than sleep trials.

Check your pillow protector too. Fully waterproof vinyl protectors let less air through and can hold heat, so hot sleepers do better with cotton or bamboo-based protectors, or ones with only a thin waterproof backing^[21].

A cooling pillow can make hot flashes more bearable, but it doesn't treat them. As many as 3 in 4 people report hot flashes in the years leading up to menopause, and night sweats are hot flashes that happen during sleep. A typical flash lasts one to five minutes^[22]. They can continue for years: among 1,449 US women with frequent hot flashes or night sweats in the SWAN study, the symptoms lasted a median of 7.4 years^[23].

One randomized trial tested a commercial cooling pillow topper in 74 women with hot flashes and insomnia who were taking hormone-blocking therapy for breast cancer. Sleep efficiency scores improved in both groups, but almost twice as much with the topper. Hot flashes fell more too, though that difference wasn't statistically significant. There was no placebo pillow, so women knew which group they were in^[24].

For treatment, The Menopause Society's 2023 statement doesn't recommend cooling techniques, because the evidence for them is limited or inconsistent. It names hormone therapy as the most effective option and recommends several non-hormone treatments, including cognitive behavioral therapy and some prescription medicines^[25].

Night sweats aren't always menopause. The NHS lists anxiety, some medicines (including some antidepressants, steroids and painkillers), low blood sugar, alcohol or drug use, and harmless excess sweating among the common causes. It advises seeing a doctor if night sweats happen regularly and wake you or worry you, come with a very high temperature, cough or diarrhea, or come with weight loss you can't explain^[26].

Fix the room first. It does more than any pillow. Most doctors suggest 65–68°F (about 18–20°C), and a fan or air conditioning helps in hot weather^[1]. In a lab study of 17 men sleeping at 90°F (32°C) and 80% humidity, a steady breeze of 1.7 m/s (about 4 mph) cut total time awake compared with still air^[27].

• Take a warm shower or bath 1–2 hours before bed. A meta-analysis found that bathing in water at 104–108.5°F (40–42.5°C) for as little as 10 minutes, 1–2 hours before bedtime, shortened the time it took to fall asleep. The likely reason is that it sends blood to the hands and feet, which speeds heat loss afterward^[28].
• Point a fan across the bed, not just around the room, so air reaches your face and the pillow surface.