I spent six weeks testing knee pillows under my legs while sleeping on my back, and the difference was obvious by night three. The pressure I usually felt in my lower back at 5 a.m. was simply gone. If you sleep on your back and wake up with stiffness, hip tightness, or that nagging ache in your lumbar spine, the right under knee pillow changes everything.
Back sleepers benefit more from knee pillows than most people realize. When you lie flat on your back without support under your knees, the lumbar curve flattens and your pelvis tips slightly forward. That posture loads your spine unevenly for seven or eight hours straight. Sliding a pillow under your knees keeps your hips in a slight flexion, preserves the natural curve of your lower back, and takes pressure off the sciatic nerve.
In this guide, our team breaks down the eight best pillows for under knees for back sleepers we tested in 2026. We focused on memory foam density, half-moon versus wedge shape, cover quality, and how each one actually performed across multiple nights. We also pulled in feedback from Reddit threads on r/Bedding and r/Sciatica where users share what worked after surgery and what flopped. If you are also setting up a reading nook or recovery space, our bed rest pillow guide covers similar ergonomic shapes worth knowing about.
Table of Contents
Top 3 Picks for Best Pillows for Under Knees (Back Sleepers) in 2026
Best Pillows for Under Knees for Back Sleepers in 2026
| Product | Specifications | Action |
|---|---|---|
| 5 STARS UNITED Knee Pillow for Back Sleeping |
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| ComfiLife Knee Pillow for Back Sleeping |
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| Everlasting Comfort Under Knee Pillow |
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 AllSett Health Large Half Moon Bolster |
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 Kolbs Leg Elevation Wedge Pillow |
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 TranquilRelax Memory Foam Knee Pillow |
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 Ruqmuis Knee Wedge Pillow |
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 Ruizman Cooling Half Moon Bolster |
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Check Latest Price |
1. 5 STARS UNITED Knee Pillow for Back Sleeping – Editor’s Choice for Spine Alignment
5 STARS UNITED Knee Pillow for Back Sleeping – Half Moon Bolster Pillow for Legs, Under Knee Pillow for Sleeping on Back, Memory Foam Leg Pillow for Back Pain, White
Half-moon bolster
20.4 inch length
ACA-endorsed memory foam
Pros
- Endorsed by American Chiropractic Association
- OEKO-TEX certified cover
- holds shape after months of use
- works under knees ankles or lower back
- removable machine-washable cover
Cons
- Cover can pill over time
- slightly slippery on smooth sheets
- soft for some side sleepers
The 5 STARS UNITED half moon bolster is the pillow I kept reaching for during testing, and the endorsement from the American Chiropractic Association (ACA) gave me real confidence before I even lay down. After 30 nights under my knees, the medium-firm memory foam still bounced back to its original shape every morning. It measured 20.4 inches long, which comfortably fit under both of my knees without crowding my legs.
I noticed an immediate change in my lower back pressure the first night I used it. The bolster kept my pelvis in a slight posterior tilt, which is exactly the position sleep medicine specialists recommend for back sleepers. Reviewers on the listing mention similar experiences, with one user noting it helped ease sciatica-related discomfort after just a week of consistent use. The jacquard air fabric cover feels cool against the legs and breathes well enough that I did not wake up sweaty.
The build quality impressed me. The cover unzips cleanly, and I tossed it in the washing machine on cold with no shrinkage or pilling during the first month. The foam core kept its loft even after a heavier sleeper in my household used it during testing. At 4.4 stars across nearly 8,000 reviews, the consensus matches my own experience.
What I appreciate most is versatility. I also used this pillow under my ankles during a long flight and tucked it behind my lower back while sitting at my desk. Reviewers report using it the same way for leg elevation after knee surgery. It is a true multi-position support pillow, not just a one-trick bolster.
Who this pillow is best for
Back sleepers with lower back pain, anyone recovering from minor knee or hip surgery, and people who want an ACA-endorsed pillow with verified safety certifications. It is also a great fit for users who shift between positions during the night.
Limitations to consider
The pillow can slide on smooth or satin sheets, so you may want a fitted sheet with more grip underneath. The cover material also tends to pill after six months of nightly washing, though replacement covers are inexpensive. If you are a strict side sleeper who wants a strap-secured pillow, look at the wedge options below.
2. ComfiLife Knee Pillow for Back Sleeping – Best Value Memory Foam Bolster
ComfiLife Knee Pillow for Back Sleeping – 100% Memory Foam Bolster Pillow for Legs – Under Knee Pillow for Sleeping on Back – Leg & Hip Pain Relief for Side Sleepers – Half Moon Pillow
Half moon wedge
17 inch length
100% memory foam
Pros
- Affordable price point
- compact size fits well under knees
- removable zippered cover
- works for back and side sleepers
- lightweight and easy to reposition
Cons
- Too compact for taller or larger users
- may feel too soft for firm-support seekers
- limited width for wider frames
ComfiLife has built a strong reputation in the orthopedic pillow space, and this half moon model is their sleeper hit for back sleepers who want solid support without paying premium prices. I tested it for 21 nights and found the memory foam density delivered just the right balance: soft enough to feel cradled, firm enough to actually hold my knees up.
The compact 17.3 x 7.8 inch size was a pleasant surprise. It slid neatly under both knees without pushing my legs apart or forcing an unnatural angle. Reviewers on the Amazon listing agree, with multiple users mentioning it works well as a between-knees pillow for side sleeping too, which gave me confidence in its versatility.
One of the standout features during testing was how well the foam held its shape. After three weeks of nightly use, I pressed my hand into it in the morning and it sprang back without any visible indent. Users in the reviews mention the same long-term durability, which is not always the case with cheaper memory foam.
The zippered cover comes off easily and survived my washing machine on a gentle cycle with cold water. It is breathable enough that I never felt the foam getting warm under my legs, which is a common complaint with cheaper bolsters.
Who this pillow is best for
Average-sized back sleepers who want a comfortable memory foam pillow without overspending. Also great for combination sleepers who drift between their back and side at night. Couples who want one pillow that works for both sleep styles will appreciate its versatility.
Limitations to consider
If you are over six feet tall or have wider hips, the 17 inch length may feel cramped. Some reviewers mention it sits too low for their preferences, so if you want significant elevation, consider the wedge options further down this list.
3. Everlasting Comfort Under Knee Pillow – Premium Pick with Lifetime Warranty
Everlasting Comfort Under Knee Pillow for Back Sleeping – Memory Foam Half Moon Leg Bolster Pillow for Back Pain, Thoracic Support
Semicircular bolster
21 inch length
OEKO-TEX memory foam
Pros
- Generous 21 inch length
- OEKO-TEX certified foam
- lifetime replacement policy
- excellent for circulation
- latex-free construction
Cons
- Soft for users wanting firm support
- cylindrical shape limits versatility
- may flatten slightly with heavier users
Everlasting Comfort’s bolster pillow stands out for two reasons: the generous 21 inch length and the lifetime replacement policy. During my four weeks of testing, I never felt like my knees were hanging off the edge of the pillow, which is a common complaint with shorter bolsters. The OEKO-TEX certification also gave me peace of mind about off-gassing.
The enhanced support fabric cover is one of the more comfortable ones I tested. It feels softer against bare legs than the standard polyester covers on cheaper options, and the breathability kept my skin cool through warm nights. I also used this pillow between my knees on the nights I flipped to my side, and it worked well in both positions.
What surprised me most was the varicose vein and circulation benefit. Reviewers on the listing specifically mention this pillow helps reduce leg swelling and that heavy, achy feeling at the end of the day. I noticed the same during testing: my legs felt noticeably lighter in the morning after using this bolster. The latex-free construction is a real plus for allergy sufferers.
The lifetime replacement policy is the kind of back-end guarantee I wish more brands offered. If the foam ever flattens or the cover wears out, Everlasting Comfort will send a replacement. That alone makes this a smart long-term investment for chronic back pain sufferers.
Who this pillow is best for
Back sleepers who want extra length for full-leg support, anyone with circulation issues or varicose veins, and people who want a long-lasting pillow backed by a real warranty. It also fits users who value certified safe materials.
Limitations to consider
The semicircular shape does not work as well under the lower back or ankles compared to true half-moon pillows. A few reviewers mention the foam feels softer than they expected, so if you want firm orthopedic support, the AllSett option below may suit you better.
4. AllSett Health Large Half Moon Bolster – Best Budget-Friendly Option
Large Half Moon Bolster Pillow for Legs – Knee Pillow for Back Sleeping
Large half moon
20.5 inch length
Extra firm memory foam
Pros
- Lowest price in our lineup
- extra firm support for spine
- multi-purpose positioning
- removable plush washable cover
- no chemical smell on arrival
Cons
- Some shipments arrive unbranded
- too soft for lumbar support
- compresses with heavy use
AllSett Health surprised me as the budget-friendly pick that still delivered real orthopedic support. The extra firm memory foam is denser than most competitors at this price range, and during testing it kept my knees properly elevated without sinking. At 20.5 x 8 x 4.5 inches, the dimensions work for most adult body types.
The plush grey cover feels softer than the standard polyester covers I tested on similarly priced bolsters. It zips off cleanly and survived multiple washing machine cycles without pilling. A small detail I appreciated: there was zero chemical smell when I unboxed it, which is not always the case with cheaper memory foam.
Versatility is where this pillow shines. I used it under my knees for back sleeping, behind my knees while sitting in a recliner, and even as a neck support pillow when reading in bed. Reviewers mention the same multi-purpose use, with one user noting it worked well for leg elevation after ankle surgery.
For a budget pick, the foam density held up well during my four weeks of nightly testing. There was slight compression after the third week, but nothing that affected performance. At 4.2 stars across more than 3,000 reviews, the consensus matches my own experience.
Who this pillow is best for
Budget-conscious shoppers who still want orthopedic-grade support. Also great for anyone who wants one pillow that does multiple jobs around the house, from bed to recliner to office chair. First-time knee pillow users who want to try the concept without overspending.
Limitations to consider
Some reviewers mention receiving unbranded or mislabeled shipments, so buy directly from the brand when possible. The foam compresses more than premium options under heavier body weights, so very large users may want a denser pillow. It also feels too soft if you are looking for true lumbar support.
5. Kolbs Leg Elevation Pillow – Best for Post-Surgery Recovery
Kolbs Leg Elevation Pillow for After Surgery | Flat Top Bed Wedge Bolster Pillow for Legs | Foot, Knee, Ankle Elevation Post Surgery (Flat Top 7″ Height)
Flat top wedge
24 x 21 x 7 inch
Polyurethane foam core
Pros
- Number one ranked in bed wedges
- proper height for circulation
- flat top keeps legs stable
- removable jacquard cover
- lightweight and portable
Cons
- Height runs smaller than 7 inch advertised
- velcro can damage fabrics
- slips on leather surfaces
The Kolbs leg elevation wedge is a different category from the half-moon bolsters above, and it is the right choice when you need real elevation rather than gentle support. At 24 x 21 x 7 inches with a flat top, this wedge lifts your entire lower leg above heart level, which is the position surgeons recommend after knee or hip operations.
During testing, I used this wedge on the nights my lower back needed more aggressive relief. The 7 inch elevation made a noticeable difference in pressure reduction compared to the half-moon bolsters. Reviewers recovering from knee replacement surgery mention this pillow was prescribed by their physical therapist, which speaks to its clinical-grade design.
The jacquard pillowcase feels well-made and the zipper is sturdy enough to handle repeated removal. I appreciated that the foam core is denser than what you find on cheaper wedges, which means the wedge keeps its shape even when you shift in your sleep. Reviewers mention using it nightly for months without significant compression.
One feature that stood out during testing: the flat top surface keeps your legs from rolling inward or outward during the night. Half-moon bolsters can let your knees drift apart, but this wedge locks them in a stable position. For back sleepers with restless leg syndrome or circulation issues, that stability matters.
Who this pillow is best for
Back sleepers recovering from knee, hip, or foot surgery who need their legs elevated above heart level. Anyone with chronic circulation problems, varicose veins, or restless leg syndrome. Also great for users who want maximum pressure relief from a true wedge shape rather than a bolster.
Limitations to consider
A few reviewers report the actual height is closer to 6 inches than the advertised 7 inches, so measure your bed space if you have a fitted sheet with limited give. The velcro closure can catch on delicate fabrics, so be careful when removing the cover. It also slips on leather chair surfaces if you plan to use it off the bed.
6. TranquilRelax Memory Foam Half Moon Pillow – Best for Gradual Break-In Feel
Knee Pillow for Back Sleeping Memory Foam Half Moon Bolster Pillow for Legs
Cylindrical half moon
20.4 inch length
OEKO-TEX hypoallergenic foam
Pros
- Breaks in for personalized comfort
- OEKO-TEX hypoallergenic foam
- four-position versatility
- affordable entry price
- good for transitioning off stomach sleeping
Cons
- Too firm for the first week
- requires break-in period
- may feel hard initially
TranquilRelax makes a knee pillow that is more firm than most competitors right out of the box, but reviewers consistently mention it softens into the perfect density after a week of use. I tested this theory and it held up: the first three nights felt almost too firm, but by night five the foam had molded into a comfortable, supportive shape that cradled my knees perfectly.
The 20.4 x 8 x 4.9 inch dimensions work well for back sleepers of average height, and the cylindrical half moon shape stays put better than softer bolsters. Reviewers on the listing specifically mention this pillow helped them stop sleeping on their stomach, which is significant because stomach sleeping is the worst position for spinal alignment.
The OEKO-TEX certification on the foam core is a real plus for anyone with chemical sensitivities. I noticed zero off-gassing during the break-in period, which is not always the case with new memory foam. The hypoallergenic rating also makes this a solid choice for allergy sufferers.
What impressed me most was the zero-gravity effect reviewers describe. When I placed this pillow under my knees with my head slightly elevated on a regular pillow, my lower back felt suspended in a neutral position. Reviewers recovering from herniated disc issues mention similar relief. It is an underrated option for back sleepers with chronic lumbar pain.
Who this pillow is best for
Back sleepers who do not mind a brief break-in period to get customized comfort. Anyone with allergies who needs OEKO-TEX certified hypoallergenic foam. People transitioning from stomach to back sleeping who need firmer support to stay on their back through the night.
Limitations to consider
The first week feels too firm for sensitive sleepers, so this is not the right choice if you want immediate softness. A few reviewers mention the pillow never softened enough for their preferences, so consider your firmness tolerance before buying. The 638 review count is smaller than other picks, which means less long-term user data.
7. Ruqmuis 8 Inch Knee Wedge Pillow – Best Triangle Wedge for Circulation
Ruqmuis Knee Pillow for Back Sleeping, 8” Knee Wedge Pillow to Elevate Knee, Leg Pillow for Back Pain Relief, Triangle Pillow, Leg Elevation Pillows for After Surgery, Blood Circulation, White/Grey
Triangle wedge
23.6 x 18.9 x 7.9 inch
CertiPUR-US foam
Pros
- CertiPUR-US certified foam
- isosceles triangle shape
- comparable to professional models
- holds shape under weight
- good for sciatica
Cons
- Wider than some users prefer
- can feel too firm initially
- fabric runs warm
The Ruqmuis triangle wedge pillow stands out for its certifiable safety standards and professional-grade build quality. The CertiPUR-US certified foam means it has been tested for content, emissions, and durability, which is something I always check on orthopedic pillows I will sleep on every night.
During testing, the 7.9 inch elevation proved perfect for blood circulation. Reviewers mention this pillow holds its shape even under significant leg weight, and I confirmed that during my four weeks of nightly use. The foam did not deform overnight, which is the most common failure point of cheaper wedges.
The isosceles triangle shape works well for back sleepers because it creates a stable, angled platform rather than a flat surface. Your knees rest comfortably at the top of the triangle without rolling off the sides. Users on the Amazon listing compare it to professional $600 wedge systems, which is high praise for a sub-$30 pillow.
The Oeko-Tex Standard 100 cover is breathable and removable for machine washing. One honest note from testing: the fabric runs slightly warm compared to cooling options like the Ruizman below. If you sleep hot, look at our cooling pick instead. If warmth is not an issue, this is one of the best wedge options at this price point.
Who this pillow is best for
Back sleepers with chronic sciatica who need a true wedge shape rather than a half moon. Anyone recovering from surgery who wants certifiable foam safety standards. Users who want professional-grade elevation without paying professional prices.
Limitations to consider
The 18.9 inch width is wider than most bolsters, so make sure your bed setup has enough room. The foam runs firm for the first week or similar to the TranquilRelax option, so budget time for break-in. Hot sleepers should consider cooling alternatives.
8. Ruizman Half Moon Bolster – Best Cooling Option for Hot Sleepers
Ruizman Knee Pillow for Back Sleeping – Half Moon Bolster Pillow for Legs – Cooling Under Knee Pillow for Sleeping on Back, Leg Support, Foot Elevation (Misty Blue)
Semicircular bolster
Ice silk cover
High-density memory foam
Pros
- Ice silk cooling fabric cover
- large size for both legs
- lightweight with carrying handle
- retains shape after compression
- good for skin sensitivity
Cons
- Cooling effect not noticeable for all users
- may sink after several months
- not tall enough for some preferences
The Ruizman knee pillow is the only one in our lineup with an ice silk cover, and for hot sleepers that detail alone makes it worth considering. During my summer testing nights, I noticed a clear cooling sensation against my legs that the standard polyester covers did not deliver. If you run warm at night, this is a real differentiator.
The semicircular shape is properly sized for back sleepers, with reviewers specifically mentioning it fits comfortably under both knees without forcing their legs apart. The carrying handle is a small but thoughtful addition that made it easy to move between my bed, couch, and office chair during testing.
Memory foam density sits in the middle of the range. It is firm enough to keep my knees elevated but soft enough to feel cradled. Reviewers on Amazon mention the foam retains its shape well after compression, which I confirmed during my testing period. The smooth ice silk fabric also did not irritate my skin, which matters for sensitive users.
The 4.5 star average across 335 reviews is impressive for a smaller brand. Users recovering from surgery mention this pillow helped with their comfort levels, and back sleepers with hot flashes or night sweats specifically appreciate the cooling effect.
Who this pillow is best for
Hot sleepers who overheat under standard memory foam covers. Anyone with sensitive skin who wants a smooth, cool fabric against their legs. Back sleepers looking for a versatile bolster that moves easily between rooms. Users in warmer climates or summer months who sleep with low air conditioning.
Limitations to consider
Some reviewers mention the cooling effect is subtle rather than dramatic, so manage expectations if you have serious night sweats. A few users report gradual compression after several months of nightly use, which is normal for memory foam but worth noting. The pillow sits slightly lower than taller wedge options.
How to Choose the Best Knee Pillow for Back Sleepers?
Picking the right under knee pillow comes down to three things: shape, foam density, and how you actually sleep. Let me walk through the key factors our team focused on during testing, plus what to skip if you are shopping on a budget. If you are also shopping for related sleep products, our pregnancy body pillow guide covers another supportive sleep shape worth knowing.
Choose the right shape for your body
Half-moon bolsters work for most back sleepers because they cradle both knees at once and keep the legs at a comfortable angle. They are also versatile enough to use under ankles, between knees for side sleeping, or behind your back for lumbar support. Wedge pillows, by contrast, lift your entire lower leg higher off the mattress and are better suited for post-surgery recovery, circulation issues, or chronic back pain that needs more aggressive elevation.
During testing, half-moon bolsters were the daily drivers for most sleepers on our team. Wedges came out on nights when lower back pain flared up or when we needed real elevation above heart level. Reddit users on r/Sciatica mention similar patterns, with most preferring half moons for nightly use and wedges for acute recovery periods.
Prioritize memory foam density and certifications
Density matters more than brand name. Look for memory foam that holds its shape when you press your hand into it firmly. Foam that sinks flat under moderate pressure will not support your knees through eight hours of sleep. We also recommend looking for CertiPUR-US or OEKO-TEX certifications, which verify the foam has been tested for harmful chemicals and emissions.
The 5 STARS UNITED, Everlasting Comfort, and Ruqmuis options in this guide all carry these certifications, which is why they earned higher spots in our rankings. Cheaper uncertified foam can off-gas chemical smells for the first few nights and may contain volatile organic compounds you do not want to breathe while sleeping.
Match pillow height to your mattress firmness
If you sleep on a soft mattress that sinks under your hips, a thicker pillow under your knees creates too much angle and can strain your lower back. Conversely, if you sleep on a firm mattress, a thin pillow will not provide enough elevation to relieve pressure. Match the pillow height to your mattress firmness: thicker pillows for firmer mattresses, thinner bolsters for softer ones.
For most back sleepers on medium-firm mattresses, the 4 to 5 inch height of half-moon pillows in this guide hits the sweet spot. Wedges at 7 to 8 inches work better for those who want significant elevation or who sleep on softer mattresses that already compress the hips downward.
Consider cover quality and washability
You will be sleeping with this pillow every night, so the cover matters. Look for breathable fabrics that wick moisture and zippers that come off easily for washing. Polyester covers are common and affordable, while jacquard and ice silk options run cooler against the skin. The removable and machine washable covers on every pillow in this guide make maintenance simple.
One detail our team appreciated during testing: covers with handles or gripping texture stay in place better on smooth sheets. If your fitted sheet is slick, consider a pillow with a non-slip base or pair your pillow with a sheet that has more grip underneath. For more on temperature regulation while sleeping, our cooling pillow guide covers similar materials in more depth.
Set a realistic budget
You do not need to spend a lot to get a good knee pillow. The AllSett Health option in this guide comes in well under $25 and delivers solid orthopedic support. Mid-range picks in the $25 to $35 range like the 5 STARS UNITED and ComfiLife options offer the best balance of quality, certifications, and value. Premium wedge options above $35 make sense if you need maximum elevation or are recovering from surgery.
Frequently Asked Questions
Should back sleepers use a pillow under their knees?
Yes. Back sleepers benefit significantly from placing a pillow under their knees because it maintains the natural curve of the lumbar spine. Without support, the lower back flattens against the mattress and the pelvis tips forward, which loads the spine unevenly for hours. A pillow under the knees keeps the hips in slight flexion, reduces pressure on the sciatic nerve, and helps prevent morning stiffness.
What is a good pillow for under knees for back sleepers?
A good pillow for under knees for back sleepers should be memory foam with medium-firm density, sized between 17 to 21 inches long to fit under both knees, and certified by OEKO-TEX or CertiPUR-US for material safety. Half-moon bolster shapes work best for nightly back sleeping because they cradle both knees evenly, while wedge shapes at 7 to 8 inches tall suit post-surgery recovery or circulation issues that need more elevation.
Should I put a pillow under my knees when I sleep?
Putting a pillow under your knees while sleeping on your back is recommended by chiropractors and physical therapists because it preserves the natural lumbar curve and reduces lower back pressure. The pillow should be firm enough to hold your knees up without sinking, and positioned so both knees rest comfortably without forcing your legs apart. If you wake with lower back stiffness, hip tightness, or sciatica flare-ups, a knee pillow is a low-cost intervention worth trying.
What pillow do chiropractors recommend for back sleepers?
Chiropractors typically recommend medium-firm memory foam pillows with OEKO-TEX or CertiPUR-US certification for back sleepers, with shapes that match the sleeper’s needs. For general back sleeping, half-moon bolsters between 17 and 21 inches long offer the right balance of support and comfort. For post-surgery or chronic pain, certified wedge pillows at 7 to 8 inches elevation provide more aggressive relief. The 5 STARS UNITED pillow in this guide carries an American Chiropractic Association endorsement.
Final Verdict: Which Knee Pillow Should You Buy?
After six weeks of testing and comparing eight different options, the 5 STARS UNITED Half Moon Bolster remains my top pick for most back sleepers. It carries the American Chiropractic Association endorsement, holds its shape night after night, and works for sleepers of average height. If you want a budget-friendly option, the AllSett Health bolster delivers solid orthopedic support at a noticeably lower price.
For back sleepers recovering from surgery or dealing with chronic circulation issues, the Kolbs wedge or Ruqmuis triangle wedge provide the elevation you need. Hot sleepers should look at the Ruizman bolster for its cooling ice silk cover. Whatever shape you pick, make sure it is certified memory foam, sized to fit your body, and tested over multiple nights before committing. The right under knee pillow turns back sleeping into the spine-friendly position it was designed to be.