Table of Contents
Why you can’t get rid of fleas
S-Methoprene: The life cycle breaker
But what about the adult fleas you already have?
How to use flea treatment effectively
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The ingredient you need to kill fleas for good!
- By Sarah
-
- August 15, 2025
- 2 MIN READ
If you’ve ever dealt with a flea problem, you know it takes time, effort and a lot of patience. You treat the pet, you hoover like you’ve never hoovered before, you wash every blanket in the house… and still, weeks later, you spot another one of those tiny acrobats hopping about.
So, what’s the secret weapon? One ingredient that can make all the difference is S-Methoprene.
Why you can’t get rid of fleas
Fleas have a life cycle that makes them super difficult to get rid of. Adults are just the tip of the iceberg—most of the flea population exists as eggs, larvae, and pupae hidden away in carpets, bedding, and that one dusty corner you never quite reach with the vacuum.
The trouble is not all flea treatments are equal. Many treatments only deal with adult fleas. You might get a day or two of sweet relief, only for a fresh wave of hatchlings to join the party. That’s where S-Methoprene steps in.
S-Methoprene: The life cycle breaker
S-Methoprene isn’t your typical "kill on contact" insecticide. Instead, it’s an insect growth regulator (IGR). In other words, it messes with a flea’s ability to grow up and reproduce.
Here’s how it works:
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S-Methoprene mimics a natural hormone in insects called juvenile hormone.
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Flea larvae exposed to it never mature into adults.
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No adults means no more eggs and the population collapses over time.
It’s a bit like locking the fleas in permanent adolescence. They simply never reach the biting, breeding stage. And because it targets developing stages rather than just adults, it deals with the hidden bulk of the flea problem.
But what about the adult fleas you already have?
Here’s where Fipronil comes in.
Fipronil is a broad-spectrum insecticide. It works by interfering with the flea’s central nervous system, causing paralysis and death. It’s fast-acting against adult fleas (and ticks too), making it perfect for immediate relief.
So, in an ideal world, you’d have:
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Fipronil
To knock out the adults currently on your pet.
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S-Methoprene
To stop the next generation from ever hatching into troublemakers.
It’s the one-two punch of flea control—deal with today’s pests and stop tomorrow’s.
Itch Flea Treatment for Cats and Itch Flea Treatment for Dogs include both Fipronil and S-Methoprene in one tailored dose for your pet, that’s easy to apply. Itch’s subscription service delivers flea and worm treatments straight to your door, every month, exactly when you need it. To get your first flea treatment completely FREE, get started by telling us about your pet here!
How to use flea treatment effectively
This means you’re killing the adults right away and sterilising the environment for the next generation at the same time.
A few tips from our experts to you:
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Treat every pet in the household, not just the one you’ve seen scratching.
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Treat your pet every month. Flea populations can take up to 6 months to fully disappear so don’t take any chances.
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Wash pet bedding regularly and vacuum frequently to pick up eggs and larvae.
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Treat your home. 95% of fleas live in your environment, not on your pet. Spray your house with Itch Flea Home Spray to kill adult fleas for up to 2 months and stop flea larvae developing for a year.
Protect your pet from fleas, ticks and lice.
Fleas, ticks and lice can be a nightmare, but with the right approach, you can take control and rid your pets and home of these bothersome pests. Remember that parasites can be persistent, so patience and regular treatment will be your best friends! By addressing both your pet and their environment, you can ensure a flea-free and comfortable living space for both your furry companion and your family.
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Right. So, you’ve vacuumed like your life depends on it, sprayed the entire house in flea spray, washed everything down to your soul – and yet, the little sods are still hopping about like they own the place. Welcome to the nightmare that is a full-blown flea infestation.
If you’re on the brink of shaving your pet bald and setting fire to your carpet, don’t panic just yet. Here’s what actually works when it feels like nothing does.
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Understanding how fipronil and s-methoprene kills fleas safely and stops fleas multiplying
Nothing kills the vibe like finding out your pet has fleas. It starts with a scratch, then another, and before you know it, you have a full blown flea infestation on your hands.
But don’t panic. Fleas might be persistent little nuisances, but science is on your side. Fipronil and S-Methoprene are two active ingredients used in spot-on flea treatments. This chemical combination knocks out a flea infestation fast and stops any fleas from bouncing back. Keep reading to find out why you should ONLY use flea treatment with Fipronil and S-Methoprene!
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Spotted a black speck? It might be a flea. If it is, you need to act fast! Don’t rush to the kitchen cupboards though, vinegar as a natural flea killer isn’t going to do much. Keep scrolling to find out why and what our experts would recommend instead…