Lufenuron does not kill parasites directly. Most people who have parasites have Candida or other fungus.
If your tongue is frequently coated or you have nail fungus you probably have a internal fungus. That internal fungus protects the parasites and makes it difficult to kill them.
I'm not an expert and not recommending anything. I'm just sharing my experience.
If you really want to study up on it all you should get Dr. Clark's book, "A cure for all Diseases". Some old information in there that isn't valid but the general knowledge makes it worth the read.