seresto flea collar review

Seresto flea collar review for dogs and cats!

If you’ve landed on our Seresto flea collar review, then it looks like your darling pet has fleas! Once they get in your home, it can be an absolute nightmare to get rid of them because of their long life cycle.

When we brought home our rescue kitten he was absolutely covered in fleas, to the point where he had scabs all over his skin from where he had been bitten!

Unfortunately, even multiple flea baths and various grocery store brand flea treatments did not get rid of the problem. These fleas were persistent, but after a lot of frustration we finally found something that really worked! The Seresto flea collar quickly eradicated our flea problem.

Seresto offered us flea relief when nothing else worked.

This solution is one of the pricier flea treatments on the market, but it lasts much longer than any other product. You’ll only need to replace your Seresto collar every 8 months, instead of every 3 months as you would with topical treatments.

It’s also a lot easier than trying to apply the topical treatments, which just end up on their fur half of the time. I was happy to find that the collars are not only effective, but they also fit securely so sneaky kitties and doggies can’t wriggle out of them.

If you’re convinced, then we’d recommend buying it from Chewy if you’d like to try one for yourself. If not, we’ve done a full write up for this product, which includes the pros, cons, potential side effects, and how to use it! Keep reading for that.

How is this different from other collars?

I was skeptical of this product at first. Flea collars are notoriously bad treatments, and many of the ones at your local store are just plain misleading in what it is they do. The reason that most collars make such poor treatment is because some of them don’t even kill fleas at all!

Many of them actually just repel the fleas, so they still hang around your house. The effective range may also be limited to the immediate area of the collar. So as long as the fleas avoid it, they can continue to live, and that makes most flea collars basically useless if you’ve already got a flea problem.

seresto is different from other flea collars
Unlike other flea collars, Seresto kills fleas on contact rather than just repel them.

Seresto collars actually have properties that kill fleas and ticks. The active ingredients in the Seresto collars are imidacloprid and flumethrin, and since there is a continuous stream of these ingredients being produced it does not give the fleas a chance to lay new eggs, because the adults will die before that ever happens.

This is the only way to break the life cycle and truly be rid of your fleas. I wasted a lot of time with other treatments before getting this collar. It’s worth every penny, and I’d have saved a lot of money if I’d just bought Seresto first.

Is Seresto better than spot treatments?

I had been using the type of flea medication that you put on the back of the cat’s neck previously, but it seems to have stopped working. Perhaps the fleas in our area have built up an immunity to it, but it was not doing the job. I tried two or three of them and some flea pills to no avail before picking up the Seresto collar.

The Seresto is still better in another regard, even if the spot treatment did work. In order for those skin treatments to kill fleas they typically have to bite the animal. This is obviously distressing for your cats and dogs, because it’s painful! With the Seresto collar, the fleas are killed on contact, and it’s a much less stressful experience for your pets.

How does the Seresto flea collar work?

The Seresto collar works by killing fleas on contact. After placing the collar on your dog or cat, any fleas that are on them will die instantly upon touching your pet. It starts to become effective within 24 hours.

Other flea treatments, such as the ones that must be ingested or be absorbed through the skin actually require the fleas and ticks to bite your cat or dog before they are effective!

is seresto better than other treatments
The Seresto collar releases a steady stream of active ingredients which kill fleas on contact.

This is obviously not ideal. Flea bites are painful, and this can lead to serious distress for your dog or cat when suddenly hundreds of fleas are eating them alive.

It also means that these treatments don’t actually protect your dog or cat from the plethora of illnesses that can be carried by fleas and ticks. By using the Seresto collar, you can kill the fleas without the risk of your pet being infected.

These Bayer flea and tick collars slowly release the ingredients in low dosage amounts over an 8 month period. These chemicals distribute themselves over the animal’s hair and skin surface, which is what makes this particular treatment so effective.

Instructions for using the Seresto collar

When you first put the collar on, you’ll notice that it’s actually very long. This is on purpose so that you can size it to your animal. The collar also comes with a break away safety clip so if your cat or dog ever manages to get caught on something their life will not be in danger.

This is especially important for cat owners, because even indoor cats are at a significant risk of hanging themselves while climbing or jumping! Break away collars are a must, and we’re happy that Seresto made sure to address this safety concern.

seresto collar how to guide

Place the collar on your pet. You should be able to get two fingers between the band and the animals neck.

seresto guide

After making sure that the collar is not too tight, snip off any extra on the band. Be sure the fit is okay before cutting.

how to use seresto collars

The collar also comes with some optional reflectors for night time visibility. These just snap into place but are not required for use. We didn’t bother with them since our cat never goes outside.

Make sure to leave room for growing pets!

If your cat or dog is still growing, then don’t snip off all of the extra band! There’s not much give to these collars so you’ll need to frequently check to make sure that it’s not getting too tight. This is especially true if you have a large breed puppy as they grow very quickly.

Seresto Flea Collar Review FAQ

Can Seresto flea collars get wet?

The collar can get wet, but it might be better for you to take it off of your pet before bathing them or letting them go swimming. According to the manufacturer, letting the collar get wet can reduce the lifespan of the treatment, and you’ll likely need to buy a new one sooner. You could cut as much as 5 months off the life of the collar if you let it get wet too often.

Are Seresto flea collars safe?

In the majority of cases, yes they are. Our cat suffered no ill effects from wearing the collar. However, each animal is an individual! They can have different levels of sensitivity to certain things, and they can have allergic reactions just like people.

That’s why it’s very important that any time you start using a new medication or treatment on your pets that you monitor them for some time after.

We would recommend checking your animal every day for at least a couple of weeks when you put the collar on them. If you start to see any redness on their neck or if the skin looks raw then this is not a good solution for them. Discontinue using the collar and look for something that is less harsh or does not make contact with their skin.

What are the Seresto collar side effects?

There are some side effects to the Seresto collar that you should be aware of. If your pet is sensitive to topical treatments or chemicals of any kind then you should look out for these things. If you see any of these symptoms present in your pet then discontinue the use of the collar immediately.

  • Raw skin
  • Chemical burns
  • Diarrhea
  • Vomiting
  • Swelling
  • Lethargy

The Seresto collars contain an active ingredient called flumethrin. This is an insecticide, but it is also mildly toxic to mammals. In many cases, these side effects are believed to have been caused by pets who have licked the collar.

This can unfortunately be a challenge with multiple pets for any flea treatments as they have a habit of grooming each other. If your animals frequently groom each other, then you may need to skip to our alternative treatments section as the Seresto collars might be a poor choice for your home.

What can I do if my pet reacts badly to Seresto?

While the collars do work well, there will unfortunately be some pets who can not use them. If you have an animal that seems to be particularly sensitive to many things, then this may not be the best choice.

Best Seresto Alternatives

For pets with severe allergies there are a couple of other options that you could consider. We have not tried all of these, but if you have a sensitive kitty or doggy, try these Seresto alternatives.

Capstar flea pills

seresto alternatives
Capstar does a great job killing fleas, but it’s not a long-term protection product.

If your pet has sensitive skin and can not handle topical treatments then these pills do kill fleas very quickly. It could also be a good solution if your pet has a bad habit of licking topical treatments off of your other pets.

The only problem is that this is not a continuous use product. This pill will kill all the fleas that are currently on your dog or cat immediately. However, it will not kill the eggs or any new fleas that hatch after those ones die.

You’ll need to treat your entire house with something that will kill any eggs that may be hiding in your carpets, and then repeatedly give the pills to your pet until the life cycle of the fleas has been broken.

This did work for killing our fleas once, but our cat got re-infested, and then we went with the collar. This is however one of the few treatments that does not require skin contact, and if he had any skin sensitivities we would probably go back to this treatment.

It’s a great product as long as you understand how it works. If your pet is an indoor only animal and you can keep new fleas from getting in your house, then this could be a good solution for you.

If you have a pet that frequently goes outside though, then you likely will just get re-infested. If your animal is sensitive to topical treatments you could try to keep fleas away by spraying the house instead of putting treatments directly on your pet in combination with this pill.


If you need a completely natural product to help your pet battle fleas and ticks, then CedarCide is a solid option. It’s a totally natural spray product, and unlike other all natural items it does not contain any ingredients which are harmful to cats and dogs.

Other products in this category often use citronella or peppermint, both of which can make dogs and cats very sick if they eat them. Instead, Cedarcide uses cedar oil. This ingredient is harmful to pest insects such as fleas, ticks and mosquitoes, but it has no effect on humans, dogs, cats or even beneficial insects like bees and butterflies.

While it is very effective in both repelling and killing these problem insects, it is slightly less convenient. You’ll need to continuously spray your pets with it, unlike the Seresto collar, which protects your animals for 8 months at a time.

If your animal is sensitive to chemical treatments though, this is a solid alternative and it’s worth a try. Plus, you can even use it to treat your house and your yard to keep all kinds of pests away!


While the Seresto collars did very well for us, pet parents should try to remember that their pets are individuals. They have sensitives and preferences just like humans do. There’s no one size fits all solution here, and the best flea and tick treatment is the one that works for your dog or cat.

We’ve tried our best to offer some insight here to help you make a decision, and these alternatives are meant to help struggling pet parents who may have trouble using the collars if their pets are allergic to them.

While we would’ve liked to recommend another collar, most of the all natural alternatives leave much to be desired. They either don’t work well or they use products which would just make sensitive dogs and cats sick anyway.

For that reason, we believe the Cedarcide and the Capstar pills are the best choices for sensitive pets who can’t use Seresto collars without experiencing bad side effects.

Michelle Rei

Michelle is a pet parent turned amateur pet product researcher. After adopting a fur baby with digestive issues caused by bad pet food, she's poured hundreds of hours into research to find the best of the best to help him and other pets live happier and healthier lives.

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