We in Florida and my sister's two dogs are on Nexguard and works great on her dogs. According to our Vet, we can start Jesse on it when he is 12 weeks. I picked up a 3 month supply when he had his last shot so we can start him tomorrow. It seems most topical treatments have not worked for her and the dogs still had fleas. We also called Pest control before we brought him home and had our front and back yard sprayed. We place him on Hartworm meds when the Vet recommends it.