A memory foam mattress has three primary components: the memory foam layer(s), the support core, and the cover. The actual memory foam material sits atop a poly foam core which prevents sleepers from sinking through to the bottom and promotes alignment. These two components are then wrapped in cover which often zips off for cleaning,
Memory foam mattresses are composed of polyurethane, which is typically made with several chemicals. Petroleum and petroleum byproducts remain on of the biggest components in the manufacture of memory foam. This can be a distinct disadvantage for those with chemical sensitivities or those seeking to be more eco-friendly.