Heat protection is a spray, mousse, or cream that you apply to wet or dry hair before heat styling with a blow dryer, flat iron, or curlers. It puts a physical barrier around the hair shaft. This barrier, often made from oils and good silicones, helps add and keep moisture while physically protecting the strands from direct heat and subsequent damage. It can also help dry your hair faster when applied to wet hair before blowdrying and extend your style's longevity.