If you are like me, you step outside on a humid day and immediately feel the transformation into one of those troll dolls that were all the rage during the 1990s, with their wild, frizzy hair standing on end. This phenomenon, known as frizz, occurs primarily due to a lack of moisture in the hair. When hair lacks adequate hydration, the cuticle—the outer layer of the hair strand—lifts up, creating an opportunity for moisture from the air to be absorbed.