Best Adjustable Pillow for Side Sleepers: Picks and How to Set Them Up

What 'adjustable' actually means on a pillow listing

Listings use the word for at least three different designs, and they don't adjust in the same way:

• Shredded fill in a zip case. Every pick on this page. You open the inner zipper and add or remove pieces of foam and fiber. Height and firmness both change.
• Removable foam layers. Contour pillows such as the UTTU Sandwich and Royal Therapy have a middle layer you can take out, giving you two to four fixed heights. They're covered on our cervical pillow page.
• Pillow-in-pillow. An inner core inside a softer outer layer, as in the Casper Original. It isn't adjustable in height the way loose fill is.

Only the first gives you fine control over height, which is why it's the focus here.

Why do side sleepers get the most out of adjustable fill?

Because the right height for a side sleeper depends on things a store can't see. Sleep Foundation says pillow loft depends on both the shape of your body and how much you sink into your mattress, and it suggests adjustable pillows if you're unsure what loft you need (Sleep Foundation).

The research agrees there's no universal number. A 2021 review found the evidence can't yet identify an optimal pillow height for the side or back (Lei et al., Healthcare 2021). A small 2025 study of side sleepers found that shoulder width combined with pillow height predicted the shape of the neck curve, yet comfort ratings were not sensitive to it (Tian et al., 2025). Put simply, your shoulders decide the height you need, but your first impression may not tell you when you've found it. A pillow you can change in small steps lets you work toward it.

7 steps to set up a shredded-fill pillow

This is the process for all five picks. Do it over a few evenings, not all at once.

1. Read the care label and listing first. Note whether the cover and inner case are removable and washable before you open anything.
2. Fluff it fully. Shake and squeeze the pillow until the fill is loose and evenly spread before judging its height.
3. Work over a bin or a large bag. Loose foam pieces scatter. Keep the spare fill bag that came in the box; you'll want it later.
4. Remove a handful or two, then zip up. Take out less than you think. You can always remove more.
5. Lie on your side for about 15 minutes. In one lab study, 70.8% of participants' necks had stabilised on a pillow by 15 minutes (Hodkinson et al., Ergonomics 2013). Judge the height after that, not after a few seconds.
6. Check your neck line. Cleveland Clinic's rule of thumb is that the pillow keeps your neck parallel to the mattress, rather than bent down or up (Cleveland Clinic). A phone on a timer or a second person helps.
7. Sleep on it for a few nights. If you wake with a stiff neck, go one handful lower or higher and repeat. Store the removed fill in its bag for top-ups.

How much fill to remove: a guide by build and mattress

No source publishes 'remove this many handfuls,' and any such number would ignore your mattress. What the sources do publish are target heights, so work toward those instead. The pillows here are listed at 6 to 8 inches when full, so nearly every side sleeper removes some.

• Average shoulders, medium mattress. Sleep Foundation says side sleepers usually need at least 4 inches. Expect to remove a fair amount from an 8-inch pillow.
• Broad shoulders. Sleep Foundation says you may need over 6 inches. You may remove very little, and the DreamyBlue's extra fill gives you headroom. More on our broad-shoulder page.
• Narrow shoulders or a smaller frame. Start lower than the 4-inch floor feels like it allows and work up. The Coop Eden is easier to take low.
• Soft mattress or topper. Your shoulder sinks in, so you need a thinner pillow. Sleep Foundation notes that if you sink deeply, even 4 inches can be too high.
• Firm mattress. Cleveland Clinic says you'll need a thicker pillow because your shoulder won't sink in much (Cleveland Clinic).
• You also sleep on your back or stomach. Set for your side, then check the other position. Side and back sleepers should check that the back position isn't too tall; side and stomach sleepers need to go much lower, since Sleep Foundation suggests 3 inches or less face-down.

Sleep Foundation's two pages give slightly different ranges: its neck-pain guide suggests 3 to 5 inches for side and back sleepers (Sleep Foundation), while the side-sleeper guide gives at least 4. Both are starting points, not rules.

Washing and caring for a shredded-fill pillow

Start with the label. Sleep Foundation says to always follow the manufacturer's specific guidelines (Sleep Foundation), and the listings for all five picks point to their own care instructions.

A few general points from Sleep Foundation's washing guide:

• Solid memory foam pillows should not be machine washed, because it can make the foam crack or degrade. Shredded foam is a different product, so go by the label rather than assuming either way.
• Most pillows that can be washed take warm water, a gentle cycle and a small amount of mild detergent.
• Dry fully before use, on the lowest heat setting over several cycles.
• Wash pillowcases at least once a week (Sleep Foundation).

For dust mites, NIEHS recommends encasing pillows in allergen-impermeable covers and washing bedding weekly in 130 to 140°F water (NIEHS). A zippered protector over an adjustable pillow also keeps the inner case clean, so you wash it less.

If you take fill out to wash a removable case, keep the foam in a bag, and put it all back before you re-measure your height.

Shredded foam vs removable layers

Shredded fill wins on fine control: you can change height by a handful at a time, and the pieces move as you change position. It loses on shape. It has no built-in neck roll, it settles over time, and it needs fluffing.

Removable-layer contour pillows give you a defined neck roll and a precise, repeatable height, but only two to four settings. Harvard Health's advice is a pillow that is higher under your neck than your head when you're on your side (Harvard Health), and contours are built that way. Shredded fill can do something similar if you push more fill toward the edge under your neck.

As for lifespan, Sleep Foundation lists 2 to 3 years for memory foam pillows. With shredded fill, the spare bag lets you top up height as it settles. For a closer look at foam in both forms, see our memory foam pillow guide and the full Coop Original review.

Which pick fits which side sleeper

Here's how I'd match the five pillows, based on the listings and Amazon's buyer summaries:

• Not sure what you need: Coop Original. Coop's site lists a 100-night trial and 5-year warranty, and the spare fill bag gives you room to experiment.
• Broad shoulders or a firm mattress: DreamyBlue, for its large size and extra foam.
• Two pillows for the price of one, or a guest room: QUTOOL 2-pack.
• Shoulder feels squashed on a rectangular pillow: Sidney Sleep Curved.
• Petite, or you like soft pillows: Coop Eden.
• You sleep hot: the QUTOOL, Coop Eden and Sidney listings all mention cooling features, though buyers are mixed on how well the QUTOOL and Eden versions work. Our cooling pillow page goes further.

Whichever you pick, it's only the best adjustable pillow for side sleepers once it's set to your body, so plan on the setup evenings above. For non-adjustable options and the wider picture, see our main guide to the best pillow for side sleepers or the side sleeper pillow shop.