PetBalance TripleGuard Plus is a monthly, triple action formula that kills adult fleas & ticks, prevents eggs and larvae from becoming adults and prevents new pests from your dog. There are two active ingredients in TripleGuard Plus: Permethrin and Pyriproxyfen (Nylar). Permethrin is an insecticide that kills and repels adult fleas, lice, and ticks. When applied, it disperses in the petâs natural skin oils into the sebum, protecting your dog for up to 4 weeks. Pyriproxyfen (or Nylar) is an Insect Growth Regulator or IGR that is particularly effective at preventing eggs and larvae from develop into infection spreading adults. EPA Reg # 67505-3-88966 & EPA Est.# 089609-FL-001