When a Wraith feeds on a human, it injects a special enzyme into the victim's bloodstream. This enables the victim to withstand the feeding process longer by making them stronger. Without it, humans succumb to the trauma associated with a feeding sooner. A user is highly resistant to Wraith stunners, tossed in unconsciousness after rematerilization from a Wraith Dart and is given super-human abilities. It was first mentioned in The Siege Part 3", when Dr. Carson Beckett found the substance in Liuetenant aiden Ford who later set up a gang of enzyme addicted men to battle the Wraith in The Lost Boys".