Most side sleepers do best around medium, a notch softer than a back sleeper would choose. I sleep on my side too. Your weight changes that starting point: choose a softer mattress if you're lighter. If you're heavier, start with a firmer mattress.
Side sleeper mattresses in brief
Around medium suits most side sleepers, but weight comes first: choose softer if you're lighter and firmer if you're heavier. Your shoulder and hip need room to sink while your waist stays supported. A hybrid is the easiest place to start if you're unsure; use our side sleeper mattress guide to compare options. For your neck, the pillow matters as much as the mattress.
Which bit are you stuck on?
- Which type to buy
- A sore hip or shoulder
- Being light or heavy
- Sharing the bed, or sleeping hot
- Buying it online
A hybrid is the easiest place to start
If you're unsure what you want, start with hybrid mattresses: pocket springs with foam or latex on top. They're my default recommendation when someone hasn't settled on a mattress type.
Memory foam mattresses feel lovely on pressure points and are great for couples because they kill movement. They do feel warm if you're a hot sleeper, whatever the cooling claim says.
Latex mattresses are bouncy and cool, and they last for years. I like latex, but the price puts people off.
Most side sleepers do best around medium
I start almost everyone at medium-firm, then move a side sleeper a notch softer, to around medium mattresses. Firmness scales are each brand's own, so judge the feel rather than relying on the label: one maker's medium is another's firm.
Firmness changes how your spine sits when you lie on your side. Leilnahari and colleagues found significant differences in spinal alignment when 25 men lay on their side on soft, firm and zoned surfaces.1 This was a small lab study of men only.
Your shoulder and hip need room to sink
Choose a softer comfort layer over a supportive core so your hip and shoulder can sink a little without losing support at your waist. A mattress that's too firm is the usual culprit when your hip feels sore after sleeping on your side. If the pain persists, see a GP.
A softer comfort layer lets your shoulder and hip sink a little while your waist stays supported.
For a stiff neck or shoulder, check the pillow before replacing the mattress, every time. Start with pillows for side sleepers. I went cheap on pillows for years until I tried a Dunlopillo, and it's been my pillow ever since.
Your weight changes the right firmness
My rule is weight first, then sleeping position. Under about nine stone, go softer than the chart says: a medium-firm feels like a plank to a light side sleeper. Start with mattresses for lighter people. Over about eighteen stone, go firmer, with a stronger spring gauge and a thicker mattress; compare mattresses for larger people with those features in mind.
Go softer if you're light and firmer if you're heavy, so each of you sinks about the same amount.
Zoned springs are a sensible idea if the zones line up with your body. Leilnahari's study concluded that a custom zoned arrangement suited heavier men with pronounced body contour. That makes the fit of the zones more useful to judge than the word "zoned" on its own.
Choose medium unless you are light or want more sink
Medium suits most side sleepers. Choose soft mattresses if you're lighter or want a deeper sink at the shoulder. If you're between the two, I'd rather you chose a medium with a softer comfort layer than a soft mattress that lets your hips drop.
Couples need edge support, and hot sleepers need cooler fillings
Edge support matters when you share a bed, so make it a priority when comparing mattresses for couples. If you want different firmness levels, choose split tension or zip-and-link. That's a better solution than settling for a compromise neither of you finds comfortable.
If you sleep hot, I'd choose springs with natural fillings; see mattresses for hot sleepers. Gel foam is the compromise if you prefer foam.
Check the springs, trial terms and base before you buy
Choose pocket sprung mattresses over open coil for a bed you'll sleep on every night. For me, open coil is only for a tight budget or a guest room: it passes movement across the bed and dips in the middle.
In a showroom, lie on your side for a full ten minutes. That's useful for ruling mattresses out. When buying online, mattresses with a sleep trial let you judge the mattress by sleeping on it, so read the collection and refund terms before ordering, then use the trial properly.
Mattress toppers can soften a mattress that's too firm, but they never fix one that sags. If your mattress dips, check the base first: slats more than about seven centimetres apart, or a broken slat, are the usual suspects.
Questions people ask about mattresses for side sleepers
Is side sleeping good for your back?
Side sleeping may be good for your back, but the evidence is limited. Cary and colleagues' review found side lying generally protective against spinal symptoms.2 Only four studies qualified, and all were self-reported, so treat the finding as encouraging rather than proof that changing your sleeping position will help your back.
Should a side sleeper buy a soft mattress?
Choose a soft mattress only if you're light or want more sink. Most side sleepers do better around medium, because a mattress that's too soft lets the hips drop. If you like a soft feel, distinguish the cushioning on top from the support underneath: you don't need to choose softness throughout.
Is memory foam good for side sleepers?
Memory foam is lovely on pressure points and good for couples, but it feels warm. Its ability to dampen movement is useful when you share a bed with someone who moves about. If you already sleep hot, consider springs instead; I wouldn't let a cooling claim settle that choice for you.
