Improves condition of fine or limp hair. Why Use ThermaSilk Volumizing Shampoo? Boosts body and volume; Revives even the finest hair; Is Heat-Activated to improve the condition of your hair. What Does Heat-Activated Mean? The ThermaSilk revolutionary formula contains heat-activated moisturizers that help lock in your hair's moisture that can be lost during heat styling - transforming a dull, lifeless texture into softer, silkier hair. Biogradable formula.