Do cooling gel memory foam toppers actually sleep cool?

Reviewer consensus is mixed. Sleep Foundation and mainstream tech press credit gel-infused and ventilated designs with reducing heat buildup, but specialist communities (r/Mattress, r/BedroomBuild) caution that gel alone is not the 'ice bed' marketing suggests, and that copper or breathable covers help more than gel infusion by itself. Hot sleepers generally do better with breathable pillow-top or bamboo-cover toppers than dense foam.