What is blockade heat defense hair serum? a glossy, lightweight serum that shields against damage caused by heat styling. who it's for perfect for all hair types, especially those in need of heat protection and moisture. why it's special if you're going to bring the heat, be sure to use protection. this hair serum is an absolute must-have for combatting the damaging effects of heat tools and blow drying up to 230 degrees. just a few drops helps to prevent against moisture loss, banishes frizz, and adds healthy-looking shine. how to use? two ways to use protection: prior to heat styling, apply 1-3 pumps to damp or dry hair. to finish a style and lock in moisture, apply 1-2 pumps throughout dry hair, focusing on the ends. what is the difference between blockade and the shield? blockade heat defense serum helps to lock in moisture for thirstier hair compared to the shield anti-humidity spray which has added style protecting benefits.