Prep, like most of our products, was named for what it does: it prepares hair by detangling; it prepares hair by evening the porosity of the hair shaft and enhancing its performance; it prepares hair for cutting (an alternative to Tonic Lotion) by lubricating the blade, dampening hair (instead of water) and helping to reveal texture as the cut progresses. Its low pH helps the cuticle to lay flatter and make hair shinier and smoother.