Mattress Topper Smell: How Long It Lasts and What Helps

You cut open the plastic, the topper starts to unroll, and the room fills with a sharp, chemical smell. The smell of a newly unboxed foam topper is well documented by bedding reviewers, and it raises an obvious question: is this normal, or should it go back? This guide sets out what the smell is, how long independent reviewers and manufacturers say it lasts, what is and is not known about the health side, and how to tell an ordinary new-foam smell from a reason to return it.

If you are still choosing a topper, the materials section of our mattress topper buying guide shows which types are least likely to smell.

What you are smelling

The US Environmental Protection Agency describes volatile organic compounds, or VOCs, as gases given off by certain solids and liquids, and lists furnishings among the household sources. New polyurethane foam, which includes memory foam, gives them off: the Sleep Foundation calls VOCs an unavoidable part of polyurethane foams, including foams that use some greener materials.

Packaging makes it more noticeable. Toppers and mattresses sold rolled in a box are vacuum-sealed soon after they are made, so the by-products that would otherwise drift away in a warehouse are held in until you open the bag at home.

How long the smell lasts

There is no single figure, and the sources do not all measure the same thing. Reviewers describe when the smell fades; manufacturers say how long to air the product before use.

Taken together: expect the worst of it to pass in the first day or two, and do not be surprised by a faint smell for a week or more. We found no source that measured this for toppers in ordinary homes, so these are reviewers’ and makers’ observations, not laboratory figures.

Which toppers smell most

The Sleep Foundation’s off-gassing guide ranks materials by how likely they are to smell. Polyfoam and memory foam are at the top. Natural latex should give off little VOC odor, although it can have a faint rubbery smell of its own, and synthetic or blended latex can smell much like foam. The same guide says third-party emissions certifications reduce the chance of a strong odor; it does not say they remove it.

Is the smell harmful?

The honest answer is that the reassuring statements come from bedding reviewers, and the regulator is more cautious about what is known.

• The Sleep Foundation says off-gassing odors pose no known serious health risks. It adds that highly sensitive people may get temporary headaches, nausea or dizziness, and that people with asthma or allergies may notice airway irritation.
• The EPA lists eye, nose and throat irritation, headaches and nausea among the effects of VOCs as a group, and says many of them have short-term and long-term health effects. It also says that little is known about the health effects of the levels usually found in homes.

Neither source measured emissions from a mattress topper, and we found no study that did, so we cannot give you a level or tell you it is safe for everyone. If anyone in the house feels unwell while the topper is airing, move it somewhere better ventilated or out of the house, and speak to a doctor if the symptoms do not clear.

What helps

1. Unpack it somewhere other than the bedroom. A spare room, or anywhere with a door you can shut and a window you can open. This is the Sleep Foundation’s main advice.
2. Get the plastic off and lay it flat. The smell cannot leave while the topper is still rolled or wrapped.
3. Move the air. Open the windows and run a fan. Increasing ventilation is also the EPA’s general advice for anything that gives off VOCs.
4. Give it a day or two before you sleep on it. The Sleep Foundation suggests a day or two; the manufacturers above say 24 to 48 hours.
5. Wash the cover if the label allows. Follow the care label exactly. Tempur-Pedic’s instructions for its removable cover, for example, are a cold wash and a cool or air dry.

One manufacturer, ViscoSoft, also suggests sprinkling baking soda over the surface, leaving it for four to eight hours and vacuuming it off. We found no independent test of whether that works on new-foam odor, so treat it as optional.

What not to do

• Do not machine-wash, soak or dry-clean the foam. Tempur-Pedic’s care instructions say not to wash or dry-clean the foam itself, and the Sleep Foundation’s advice for foam and latex cores is to spot clean and avoid soaking.
• Do not rely on air freshener. Some sellers suggest it. The EPA lists air fresheners among household sources of VOCs, so a spray covers the smell without clearing the air.
• Do not let the return window run out while you wait. Note the last return date on the day the topper arrives.

What a CertiPUR-US label tells you about smell

CertiPUR-US certifies polyurethane foam, and one of its tests is for emissions: certified foam must emit less than 0.5 parts per million of VOCs in a small chamber test. That is a limit on how much comes off the foam. It is not a promise that you will smell nothing, and the program’s own FAQ says that few things do not off-gas to some extent. Our guide to what CertiPUR-US means covers the rest of what the label does and does not tell you.

The mark also applies only to the foam, not to a cover or anything else in the product. That limit matters more for mattresses than for toppers; our guide to fiberglass in mattresses explains why.

The two-week mark is our own rule of thumb, based on the Sleep Foundation’s range of several days to a few weeks. It is not a safety threshold.

If the smell appears months later

A smell that turns up on a topper you have owned for a while is not off-gassing, which is strongest on day one and fades. The likelier cause is moisture. The Sleep Foundation notes that moisture can leave lasting stains and odors in a mattress, and ViscoSoft’s advice page points to sweat and spills as the source of smells that build up over time. A washable cover or a protector over the topper is the usual defense. A waterproof protector can make the bed warmer, though: see why a mattress topper sleeps hot before you add one.

How we researched this

We read the Sleep Foundation’s published testing notes and articles on off-gassing, the EPA’s guidance on volatile organic compounds, the CertiPUR-US program’s own description of its tests, and two manufacturers’ care and advice pages. We did not unbox, smell or measure any topper ourselves, and where the sources disagree we have shown each one.