AquaGuard coats your hair's cuticle layer to:A) Stop chlorine and other nasties from penetrating your hair follicles. When chlorine gets in, your natural oils come out. That's why it is better to prevent damage than attempt to repair it. AquaGuard stops damage before it starts.B) Prevent oxidized copper (and other minerals) from bonding to your hair. Bonded minerals weigh down your hair, leaving it flat, dull, and discolored. (Bonded oxidized copper is also what causes blondes to turn green... yuck!) AquaGuard's protective layer does not allow these minerals to get ahold of your hair like they would without it!