The Prana Lotus Asana is an all foam(not memory foam) mattress. Normally would exceed my budget but found a clearance model. That was my lucky day as my hip pain as a side sleeper has been totally alleviated. This mattress feels like floating, not sinking as a memory foam would. It does sleep a bit warmer than my innerspring did so a lighter comforter is needed but that's an easy fix. Highly recommended even at full price, steal of the year on clearence!