Before committing to a mattress topper, there are several things you should keep in mind.

Material

If you’re dealing with back pain, you should try sticking to mattress toppers that are made from either latex or memory foam, says Dr. Koivuranta. “Latex will be a bit firmer, generally speaking, and memory foam a bit softer.” The type that you opt for will depend on your back pain. “For back pain that is more mechanical in nature and not as arthritic, a firmer sleep surface is better, hence latex,” says Dr. Koivuranta. In more advanced cases of back pain, memory foam works better for avoiding pressure on the joints.

For the average person, Dr. Koivuranta recommends a more firm sleeping surface, since it’ll help maintain or support a healthy spine. You can also opt for other materials like feathers, polyester fibers, or other naturally-filled products that may be less supportive, but still feel really comfy. This may not be a good idea if you suffer from lots of back pain, though, Dr. Koivuranta says.

Firmness

Those with back pain should seek a topper that’s more on the firm side. “If firmness was graded on a scale from 0 to 10, 0 being no support, like a waterbed perhaps, and 10 being firm like the floor, it’s generally thought that seven is close to the sweet spot,” says Dr. Koivuranta. It’ll vary from person to person, but a person that sleeps on their side should have enough support to keep the spine in a straight line with just enough give to accommodate the pelvis and shoulders, he adds. A back sleeper should opt for a topper with some give near the butt and mid-back. This will allow it to support the natural curves in the low back and neck, says Dr. Koivuranta. Back sleepers should also use a bolster under the knees and a proper pillow, he suggests.

Thickness

The thickness will depend on the reason you’re shopping for a mattress topper. “If a mattress is newer and the person finds that it’s slightly not providing the right support or cushioning, a thinner topper in the two-inch range will work,” Dr. Koivuranta says. If you’re shopping for an older mattress that’s lost its support or cushioning, a four-inch option can help firm it up, improving the quality of sleep for the sleeper,” he adds. Your topper’s thickness will also depend on factors like body type, size, and weight. Those with a larger stature may benefit from a more thicker option, Koivuranta says.