Best IGR for Fleas

7 Best IGR for Fleas in 2024 Reviewed

IGRs, Insect Growth Regulators, are pest management products that break the flea life cycle to control fleas. What’s the best IGR for fleas on the market.

IGRs inhibit molting in insects (exoskeleton development) and thus prevent fleas from reaching the mature stage where they lay eggs. Check IGR for Fleas. 

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1. Our #1 Pick: CS 82005202 I. G Insect Growth Regulator

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The CS 82005202 included the Pyriproxyfen-insect growth regulator that kills developing egg and larval stages of the flea life cycle. 

Pyriproxyfen has very low toxicity to humans or animals when used as directed but it can be deadly to insects. It’s in many products because it has an or animals.

CS Pivot IGR can offer effective control for up to seven months against fleas via its unique pyrethroid-insect growth regulator technology – but prevent direct sunlight.

Despite containing the same concentration and active ingredient of NyGuard, this commercial-grade IGR is costly but it is sold in 3.72 ounces.

You will need to mix your CS Pivot 10 with a pesticide that is approved for killing adult fleas. 


  • Has IGR pyriproxyfen (kills eggs) and Prallethrin (offers quick knockdown?
  • Safe for Pets
  • Kills fleas, spiders, and bed bugs

A great feature about Alpine IGR-20 795903 is that it does not require any measuring or mixing – simply shake the can and start spraying!

2. #2 Pick: Precor Plus IGR-Fogger Flea Control

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The non-repellent dinotefuran formulation is also a non-residual (contact killing) that you can use as an injection treatment or on the spot, void, crevices, and cracks.

Further, Alpine IGR-20 795903 contains IGR pyriproxyfen (kills eggs) and Prallethrin that offers quick knockdown for adult fleas. Plus the synergist will enhance the action of these ingredients.

Parasitic fleas (on dogs and cats) are a common worry among families with pets, but they can be picked up by anyone who lays or walks on the grass – but IGRs will help. 

Once you’ve sprayed Alpine IGR-20 795903, the adult fleas will die fast and you won’t have eggs developing for months – plus no mess will be left behind.

The Good:

  • Pyriproxyfen-insect growth regulator
  • Offers 7-months flea-protection
  • Value for money

The Bad:

  • Won’t kill adult fleas

3. #3 Pick: Adams Plus Tick & Flea Mist + IGR

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Does IGR Kill Flea Eggs? Gentrol IGR? – Well, Yes, IGRs will kill flea eggs and flea larvae by disrupting their molting; which is the flea’s normal development and growth process.

  • IGRs kill both adult and immature flea life stages – adult fleas won’t reproduce, eggs won’t hatch, and flea larvae die before developing fully.
  • Insects grow by molting (birth control), where they shed their old exoskeleton to make way for a new one.
  • IGRs, or insect growth regulators, can help prevent fleas from reaching the mature stage where they lay eggs.
  • This in turn lowers the number of pests because their immature stages cannot reproduce.

IGRs work by mimicking natural hormones that inhibit insect growth, so they mostly affect immature insects in their larval or nymph stages of life; which prevents them from reproducing and spreading.

This may be a more long-term solution than pesticides because while they don’t work on adult fleas, they will still keep new generations from appearing.

  • They are also safer for the environment and pets.

Does Gentrol IGR work on fleas?

Well, Gentrol IGR may not kill adult fleas, but it does stop them from reproducing. It is an insect growth regulator that prevents immature eggs from maturing past a certain stage of development.

  • With a combination of the adult flea-killing chemical and Gentrol, you get two for one – plus an IGR that will help keep new generations from appearing.

How Does Gentrol Work? The active ingredient in Gentrol insecticide – (S)-Hydroprene – is designed to penetrate the exoskeleton and cause adult sterility and kill immature stages of fleas, roaches, and bed bugs.

4. ZOECON Precor IGR for (Pet Safe) indoor control 

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This product contains (S)-methoprene, which is a synthetic pyrethroid that is used as a long-residue insecticide. 

Last year, for 3 months or so in Los Angeles, my mum was unable to go outside to mow because there would be bugs all over and it was a hot summer.

  • The fleas lived in shaded areas. So, they got on the kids when they played outside. Then, the fleas got inside.
  • It was horrible. But they used ZOECON Precor IGR successfully.

The product is in the middle of the cost spectrum (safe for pets), but it won’t work well outdoors – especially in the sun.

The Good:

  • Contains (S)-Methoprene
  • Long residue-effect
  • Safe around kids and pets
  • Flea-treated about 1,500 sq. ft.

The Bad:

  • Doesn’t work outside
  • Requires the use of a 1-gallon sprayer
  • Requires the addition of a pesticide for adult fleas

5. Alpine IGR-20 795903 Prallethrin + Quick Knockdown

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Alpine IGR-20 is a ready-to-use and pet-safe aerosol that will give you hassle-free control of fleas in your yard – it contains synergist, pyriproxyfen, and Prallethrin as the ingredients. 

This product quickly kills fleas with a pyrethroid (single knockdown) and also controls immature stages of the flea life cycle for about seven months.

  • After trying a variety of flea control methods to no avail for over a month now, I was advised to pick Alpine IGR-20.
  • It killed all the fleas on my dog’s bed and in our home instantly.

If you’re serious about killing bedbugs and fleas, I highly recommend Alpine IGR-20.

  • Even after one treatment with this pesticide spray, you’ll notice most of your infestation is gone.
  • Pay particular attention to hard-to-reach places like crevices along the windowsills and doorjambs.

You are likely going to need two cans to spray even the beds, drapes, and fabric furniture.

The Good:

  • Has IGR pyriproxyfen (kills eggs) and Prallethrin (offers quick knockdown)
  • Safe for Pets
  • Kills fleas, spiders, and bed bugs
  • Flea-treats 2625 sq. ft.

The Bad:

  • Lower coverage

6. CSI-Tekko Pro IGR Inhibits Fleas re-infestation

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In the past, we were unable to spend any time on the deck because mosquitoes swarmed us so quickly.

Fortunately, CSI-Tekko Pro IGR overcame our deck mosquito and flea problem. 

Tekko is an IGR that messes with the fleas’ and mosquitos’ ability to reproduce.

  • Coupled with Talstar P, Tekko can reduce mosquito and flea populations by over 90-percent in as little as two weeks.
  • I was infested with roaches and used other products before this one in the past but they only covered up the problem.

After two applications, there has not been a roach sighted.

Using Tekko Pro IGR in conjunction with Harris Boric Acid, Advion gel bait, and Invicta Gold will easily exterminate German Brown Cockroaches.

The Good:

  • Contains Pyriproxifen IGR
  • Great for flea-treating kennels, carpets, or furniture
  • Cheat IGR for fleas
  • Offers 7-months flea-protection

The Bad:

  • Won’t exterminate adult fleas

7. MGK NyGuard IGR for Warehouses, Hospitals, Motels

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MGK NyGuard IGR is a broad-spectrum insecticide that contains the active ingredient Pyriproxifen – great for flea-treating kennels, carpets, or furniture. 

  • It offers up to seven months of protection from adult fleas plus exterminating the other flea stage.
  • But its active ingredient (Pyriproxifen) is weaker compared to those in Pivot and NyGuard.

This product is marked for use in food-processing plants, bakeries, and restaurants. It’ll exterminate mosquitoes, flies, fleas, cockroaches, and even ants.

Per the manufacturer, you should mix MGK NyGuard IGR with another pesticide to exterminate adult fleas and juvenile fleas too.

The product is effective, my friend reports that they’ve seen a significant reduction in the number of fleas on their pets.

They chose to treat with MGK NyGuard IGR instead of using a flea bomb.

The Good:

  • Contains Pyriproxifen IGR
  • Cheap IGR
  • Effective for non-food or food areas

The Bad:

  • None

IGRs and Flea Control – Selecting the Best IGR

There are 2 major classifications of IGRs for fleas, based on

  1. The active ingredient
  2. Added chemicals like knockdowns and synergists

1. (S)-Hydroprene

The active ingredient in Gentrol is (S)-Hydroprene. This chemical has been found to work for killing both fleas, moths, beetles, and cockroaches.

  • The knockdown in Gentrol has been found to work for killing both adult fleas and their larvae.
  • This IGR can be used on carpets, upholstery, cracks and crevices, non-food areas where pets are present indoors only.

2. Pyriproxifen

Pyriproxifen is another IGR for fleas that are applied directly to your dogs and cats.

  • This chemical has been found to work for killing larval stages of fleas, as well as moths, cockroaches, beetles, and ants.
  • The knockdown in this product has also proven useful against adult fleas indoors only on carpets or upholstery with no food present.

It can be used outdoors if pets are not around but it must stay dry when applied outside because rain and direct sunlight will affect its effectiveness.

3. Dinotefuran

Dinotefuran is classified as a neonicotinoid as it’ll damage the fleas nerve synapses’ receptors in the CNS. This is an insecticide, not an IGR.

Sentinel is a fast-acting product that works as an adulticide, and its residual effect will last for about 3 months.

3. Methoprene

Methoprene is available in either r-methoprene or s-methoprene and it’s a good choice for fleas because of its low toxicity to humans, pets, and wildlife.

S-methoprene works like an IGR; it’s sprayed around on the carpets or upholstery.

  • This product should be used as soon as possible to prevent new eggs from hatching.
  • If you choose this option it’s important not to let it dry out because rain will wash the chemical away before it has been able to activate.

4. Prallethrin

Prallethrin is an insecticide from the pyrethroid family and it’s often used alongside an IGR.

Prallethrin is a chemical generally used for the control of food-contaminating and nuisance insects like ticks, fleas, roaches, and ants.

Related: See the Top Flea Sprays Today

How will IGRs Kill Fleas?

An insect growth regulator is an insecticide that disrupts the way that insects grow (in the molting process) and reproduce. They’ll control fleas, bed bugs, mosquitoes, roaches, and ants.

  • IGR-treated fleas won’t hatch and the flea larvae don’t grow to lay eggs – they die prematurely.
  • Insect growth regulators work by interfering with an insect’s life cycle at a crucial point (molting process), for example when it molts or mates.
  • The IGR blocks this critical part of their development so they can’t reach sexual maturity, reproduce or cause damage to humans and pets.

Exterminators refer to insects that are trapped in their old exoskeleton as “i-grr-ed,” since they will frequently be seen as being warped or mutated due to bodies attempting to grow in the old exoskeleton.

  • The method is hyper-accelerated growth, in which the insects bypass normal sexual growth (becoming neutered adults) and won’t reproduce.

Mixed pesticide application protocols like the one illustrated in this video are necessary to use most IGRs.

Are IGRs For Fleas Safe to Kids and Pets?

IGRs are pesticides that work on fleas – mimicking insects’ hormones. So, IGRs do not pose a health risk to kids or pets but some inert ingredients may not be safe.

Any chemical pesticide has a certain level of risks, but children are at a greater risk than adults; Infants and toddlers have a higher relative body weight compared to adults.

Young infants’ activities make them especially exposed to any pesticides for fleas as they crawl around and eat everything.

The first pesticide to consider if you are concerned about the safety of your children is flea collars.

  • Flea collars can be a safe way to prevent or control an infestation with fleas in pets, but they do have some risks for kids – including ingestion and inhalation of pesticides as well as skin contact/allergic reactions.

For other types of pet treatments like oral medications or topical applications (e.g., shampoos), keep all powders, liquids, tablets, etc away from children and pets.

Related: Controlling Fleas on Carpet? Use this…


In conclusion, this article is about different IGR treatments for fleas. A study was done to find the best IGR for fleas;


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