The question is "which product", but the reason people cycle through five products and conclude they are all fake is almost never the product.
About 5% of a flea population is on the animal. The rest — eggs, larvae, pupae — is in the bedding, the carpet, the sofa and the cracks in the floor. Kill the 5% and the house restocks it within a week. Then you blame the product and buy a different one, and the same thing happens.
So the actual protocol:
- Treat every animal in the house on the same day. Every one. The untreated cat upstairs is the reservoir.
- Wash all bedding hot, and keep washing it weekly for a month.
- Vacuum daily for two weeks — floors, under furniture, along skirting. Empty it outside every time. Vacuuming also triggers the pupae to hatch, which sounds bad and is exactly what you want: they hatch into a treated environment instead of waiting three months.
- Treat the environment where the animal sleeps, not just the animal.
- Keep going for three months. The pupal stage can sit dormant and nothing kills it. Three months covers the full cycle. Everyone stops at three weeks.
On resistance, since you asked people to say their city: Lahore, and yes, I have seen a spot-on that worked for years stop working. That is real. But before deciding a product has failed, check the three boring things first: was the dose right for the actual weight, did you part the fur and get it onto the skin rather than onto the coat, and did you bathe the dog within 48 hours either side. Those three account for most "it did not work" cases in my experience.
Ticks specifically: the brown dog tick lives in the house, in wall cracks and behind the kennel, not in your garden. If you have an infestation you have a building problem. This is the same point that came up in the tick fever thread and it is the one that actually breaks the cycle.
Removing a tick: fine-tipped tweezers, as close to the skin as you can get, straight and steady pull. No matches, no petrol, no nail polish. All of those make the tick regurgitate into the wound, which is precisely how disease gets transmitted.
