What it is
A protector is a thin, usually waterproof layer that fits over the mattress like a fitted sheet, or zips all the way round it as an encasement. It keeps sweat, spills, bedwetting and stains out of the mattress, which matters because many warranties are voided by stains, and it's far easier to wash than a mattress.
The waterproof membrane is usually polyurethane (quiet and fairly breathable) or vinyl (cheaper, crinklier and hotter). Zippered encasements are also sold for bed bugs, which needs one tested for that purpose.
How strong is the evidencenone
Protectors are hygiene and warranty kit, not health products. Allergen-proof encasements reduce mite allergen in the mattress, but large randomized trials found they didn't improve asthma or allergic rhinitis when used alone.
The claims you’ll meet3 checked
Protects your mattress and your warrantyHolds upA waterproof layer keeps stains and fluids out, and many warranties exclude stained mattresses.
An allergen barrier relieves allergies or asthmaFalseTwo large trials found no clinical benefit from impermeable covers used alone.
Cooling or phase-change protectors keep you coolUnprovenPhase-change finishes absorb a little heat briefly, and a waterproof membrane tends to add warmth.
What to look for5
- ✓A polyurethane membrane rather than vinyl if you want it quiet and less sweaty.
- ✓A deep enough skirt to stay on your mattress plus any topper.
- ✓Washing and drying instructions you can follow at home.
- ✓For bed bugs: a full zippered encasement tested for bed bugs, left on for at least a year.
- ✓For bedwetting or incontinence: an absorbent top layer over the waterproof backing, and a spare for night-time changes.
What to skip2
- ×Allergy-cure claims for encasements.
- ×'Cooling' and mineral-infused 'recovery' fabrics.
Take care2
- !Asthma or allergies: covers are at best one part of a plan. See a clinician about treatment.
- !Cribs: use only a protector made for that crib mattress and fitted tightly, with no loose plastic or extra padding.
The studies2 cited · checked against PubMed
Control of exposure to mite allergen and allergen-impermeable bed covers for adults with asthma ↗Woodcock A, Forster L, Matthews E, Martin J, Letley L, Vickers M, et al. · New England Journal of Medicine · 2003RCT
1,122 adults with asthma got allergen-impermeable or ordinary bed covers. Mite allergen in mattresses fell at 6 months, but peak flow and the ability to stop inhaled steroids did not differ between groups, including in mite-sensitive patients.
Evaluation of impermeable covers for bedding in patients with allergic rhinitis ↗Terreehorst I, Hak E, Oosting AJ, Tempels-Pavlica Z, de Monchy JG, Bruijnzeel-Koomen CA, et al. · New England Journal of Medicine · 2003RCT
279 people with mite-allergic rhinitis used impermeable or ordinary covers on mattress, pillow and duvet for a year. Mite allergen in mattresses fell, but symptoms and nasal provocation results did not improve.