MedCline
MedCline Acid Reflux Relief System
Memory foam + polyurethane wedge
Updated October 2026
Best Knee Pillows for Side Sleepers
A pillow between the knees stops the top leg from dragging the pelvis into rotation — the hidden cause of most side-sleepers' hip, SI-joint, and lower-back pain. These 5 options held alignment best in our overnight testing.
Compare the top picks and current prices
Start with the fit and construction, then check the retailer's current price and return terms. Shopping links may earn Sleep Sage a commission at no additional cost to you.
Coop
Coop Original Adjustable Pillow
Cross-cut Memory Foam & Microfiber Blend
Eli & Elm
Eli & Elm Side Sleeper Pillow
Latex and polyester blend (adjustable)
Key Lab Findings
- Thickness
- The right spacer thickness depends on leg shape, sleep position and personal comfort
- Source: Sleep Sage editorial analysis
- Shape
- Contour and strap designs can make a knee pillow easier to keep in place
- Source: Sleep Sage editorial analysis
- Comfort
- Treat symptom relief claims cautiously and seek care for persistent pain
- Source: Sleep Sage editorial policy
What a Knee Pillow Solves
Pelvic Alignment
Without a knee pillow, the top leg drops forward and twists the pelvis — loading the SI joint and lumbar discs for 6–8 hours straight
Root cause of morning back painBursitis Relief
Keeping the top hip stacked prevents compression of the greater trochanter bursa — critical for hip bursitis sufferers
60%+ pain reduction reportedThickness Matters
Too thin and the knees touch; too thick and the hip splays outward.
5–7in sweet spotShopping note: Placement is everything: the pillow should sit between the thighs/knees — not the ankles — with the top leg parallel to the mattress. If you wake with the pillow on the floor, you need a contoured hourglass shape that hooks the leg, or a full body pillow that can't escape. Pregnant testers got the best results pairing a knee spacer with belly support.
#1
9.4/10
Memory foam + polyurethane wedge
Research evaluation — full lab score pending
9
Comfort
9.5
Support
Medium-Firm
Firmness
Manufacturer cites FDA clearance and a clinical study (not independently verified)Integrated arm pocket designed to ease shoulder pressureLeft-side positioning matches medical recommendations
$249$319
#2
Editor's Choice
Coop Original Adjustable Pillow
Consumer Reports Recommended - fully customizable loft
9.5/10
Cross-cut Memory Foam & Microfiber Blend
Research evaluation — full lab score pending
9.6
Comfort
9.5
Support
Adjustable (Medium)
Firmness
Consumer Reports RecommendedFully adjustable loft - add or remove fillCertiPUR-US and GREENGUARD Gold certified
$89$99
#3
Best Shoulder Cutout
Eli & Elm Side Sleeper Pillow
U-shaped shoulder cutout and adjustable fill for side sleepers
9.3/10
Latex and polyester blend (adjustable)
Research evaluation — full lab score pending
9.5
Comfort
9.2
Support
Adjustable
Firmness
Curved cutout makes room for the shoulderAdjustable fill for custom loftOrganic cotton cover
$119$149
#4
Derila Memory Foam Pillow
Budget ergonomic contour pillow for back and side sleepers
8.2/10
Solid ergonomic memory foam with cervical wave contour
Research evaluation — full lab score pending
8
Comfort
8.6
Support
Medium-Firm
Firmness
Outstanding value — often under $40 on promotionErgonomic wave contour supports the cervical curveSuitable for back and side sleepers
$39.99$79.99
#5
9/10
Shredded Talalay Latex
Research evaluation — full lab score pending
9.2
Comfort
9
Support
Medium (adjustable)
Firmness
Talalay latex is bouncy and breathableAdjustable loft — remove fill to customize365-night trial matches their mattresses
$165$195
Frequently Asked Questions
Does a pillow between the knees really help back pain?
Yes. In side sleeping, the unsupported top leg rotates the pelvis, twisting the lumbar spine for hours. A between-knees pillow keeps the pelvis stacked.
What thickness knee pillow do I need?
Wider hips need more. The test: lying on your side with the pillow in place, your top leg should be parallel to the mattress — not angled down (too thin) or lifted (too thick).
Knee pillow vs body pillow — which is better?
A body pillow is more versatile (supports head, hip, and knee at once and can't fall off the bed), but a dedicated knee pillow is easier to reposition and cheaper. If you also want arm or belly support — especially during pregnancy — choose a body pillow.
Where exactly should the knee pillow go?
Between the mid-thighs to knees, with both knees slightly bent. Placing it at the ankles is the most common mistake — it leaves the hip free to rotate and defeats the purpose.
Looking wider than best knee pillows for side sleepers? Browse all pillow reviews to compare every pillow we have reviewed on loft, fill, cooling and price.