What it is: Joico JoiWhip Firm Hold Design Foam”¨, $16.99What it does: Keeps your favorite style in place while nourishing, strengthening and moisturizing your ‘do. Translation: Keeps waves well-defined.Why it works: To get body and fullness to last, researchers isolated two styling polymers (molecules that bond to the hair) that are flexible and humidity-resistant. Together, they hold your hair up against the bad-hair-day-inducing forces of wind, heat and UV rays (which weakens hair overtime, if it weren’t bad enough!).Each time you apply, you’re also strengthening hair at its core. Damaged hair has missing peptides—shorter chains of amino acids that make up your hair protein. Joico’s trademarked Bio-Advanced Peptide Complex adheres to your hair shaft to provide the missing peptide link from the cuticle (outer hair layer) to cortex (inner layer).The complex goes further to seal a protective molecular shield around your hair, as well. Phew, that’s a whole lot of chemistry for one head of hair!Thanks to essential fatty acids of Kukui Nut Oil (used for centuries in Hawaii) and Evening Primrose oil, you’re left with a soft, shiny style that stays—without the stiff “crunch.”