A glossy, lightweight amika Blockade Heat Defense Serum that shields against damage caused by heat styling. 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 450 degrees. Just a few drops helps to prevent against moisture loss, banishes frizz, and adds healthy-looking shine.