LOreal Paris Elvive Fibrology Thickness Booster is for thicker hair. What if science could give you thicker hair than nature did? A breakthrough in the science of hair, LOreal Laboratories have created our 1st haircare range proven to give thicker hair wash after wash. The Thickness Booster contains an intensive thickening formula with our highest concentration of Filloxane (5%), specially developed to give thicker looking hair. Instrumental tests on sensitised hair with shampoo and conditioner.