Gel mattress toppers are becoming popular, especially if you’re a hot sleeper and wake up sweat slicked by the morning. A gel mattress topper usually has gel beads added or gel infused into synthetic memory foam and can contain concerning chemicals. Also, memory foam is usually made from low-resistance polyurethane to make it viscose and elastic. If you do buy a gel mattress topper, check for appropriate certifications ensuring it is low polluting and is free from harmful chemicals. An alternative to a gel mattress topper is a wool mattress topper that helps you sleep cooler naturally.