BRAND NEW - UNOPENED - UNUSED Thicken your hair EVER-y time you blow dry. EVER.THICKEN is our thickening, heat-activated style extender featuring Long Chain Polymers and a volumising Cotton Sprout Complex that creates thicker, fuller hair. Activated by the heat of your blow dryer, this weightless spray also helps lock out humidity and extend your style for a long-lasting, frizz-free finish.