Bayer Seresto Flea Collar vs NexGard Chewables for Dogs

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There are many joys of having a dog part of your life.

However, fleas and ticks are not amongst them.

Fleas and ticks are prevalent parasites found almost anywhere you go outside. Your dog only needs to brush up against the tree or roll around in the grass to pick up fleas and ticks.

The good news is there is an abundance of great products and treatments available on the market to help eliminate the risk of your dog getting infested with fleas and ticks.

Our article, Seresto vs NexGard, compares two excellent flea and tick products to help dog parents make an informed decision on which one is best for their pup.

I believe both products have their benefits; if I had to pick just one, it would be NexGard.

I recommend it because first, I’ve used it and know that it’s safe and effective even with younger puppies.

And second, because it is useful for treating more than just fleas and ticks.

Seresto – Collar

  • Active Ingredients: Imidacloprid and Flumethrin
  • Type: Collar
  • Duration: 8 Months

Seresto is one of Bayer’s flea and tick products. It was launched in 2011 and is effective at both killing and repelling these parasites.

Bayer Animal Health is a globally recognized company that has been in business since 1919[1].

The Seresto collar is made from a polymer matrix and manufactured with insecticides that last up to 8 months.

The pesticides are slowly released into the dog’s skin then spreads over their entire body.

Flea and ticks are not the only things Seresto kills; it also takes care of biting lice and sarcoptic mange.

And, Seresto interrupts the flea life stages from egg to adult.

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Seresto collars work pretty fast when it comes to killing parasites, and takes care of fleas within twenty-four hours and ticks within forty-eight hours.

Caution should be exercised on the first day your dog wears the Seresto collar since it is at its greatest potency.

It is advised children and other pets stay clear of the collar for at least a full day after attaching the Seresto collar. However, it is never recommended that children or other pets come in contact with the collar.




  • The Seresto collar is not waterproof
  • May cause skin sensitivities in humans if they come in contact with the collar

If Seresto sounds like the flea collar for your dog, click here to order!

If you want to learn more about this flea preventative, check out our comprehensive Seresto review!

NexGard – Chewable Pills

  • Active Ingredients: Afoxolaner
  • Type: Chewable Tablet
  • Duration: 1 Month

NexGard is a Boehringer Ingelheim Group product.

Boehringer Ingelheim Group’s focus is on improving the quality of life of humans and animals. They are a family-owned global company.

Ultimately, Afoxolaner attacks the central nervous system, causing the parasite to become overstimulated, killing the flea.

Because the nervous systems are different in dogs, afoxolaner should not affect the dog.

NexGard effectively kills adult fleas, mites, and various tick species like Lone Star ticks, American dog ticks, Black-legged ticks, and Brown dog ticks[2].

Related: Nexgard vs Nexgard Spectra: Which Flea Treatment is Right for You and Your Pup?

Nexgard Spectra Flea and Heartworm Medication Front of Box

Additionally, NexGard works to rid dogs of Demodex mites responsible for demodectic mange, Sarcoptes mites that are the cause of sarcoptic mange, and Otodectes mites or ear mites.

NexGard does not repel or prevent fleas, ticks, or mites.

For NexGard to work, the parasite must bite your pup and ingest the poison to kill it.

NexGard starts killing fleas in as little as four hours after your dog consumes the chewable, and 48 hours for ticks.

See how Nexgard compares to Frontline Plus and Credelio



  • Works in as little as four hours
  • The beef-flavored chewable is easy to give to your dog
  • Safe for puppies eight weeks old and older
  • Only FDA-approved tick product to prevent Lyme infection[3]


  • The parasite must bite the dog for the medicine to work
  • Does not repel fleas and ticks

If you are ready to order NexGard click here to get your order started!

If you want to know more about this chewable flea treatment, read our NexGard review!

Face to Face

I think it is easiest to view things side by side when comparing products. It saves from needing to scroll or toggle back and forth between screens.

I have put together a side by side comparison for Seresto and NexGard to make it easier to compare the two.

Kills Fleas and TicksYesYes
Repels Fleas and TicksYesNo
Other ParasitesLice and Sarcoptic MangeDemodex mites, Sarcoptes Mites, and Otodectes mites 
Active IngredientImidacloprid and Flumethrin Imidacloprid, Permethrin, and Pyriproxyfen
Duration8 Months1 Month
Prescription Needed?NoYes
Waterproof or Water ResistantWater ResistantWaterproof
Price per Month (Based on a Small Sized Dog)$4.12$18.99
Minimum Age Requirement7 Weeks8 Weeks

Side Effects

All flea and tick treatments have side effects, though they vary by brand and type.

Here are the most common side effects for Seresto and NexGard:


  • Skin irritation and rashes
  • Itching
  • Excessive Drooling
  • Shaking
  • Vomiting
  • Decreased Appetite
  • Sleepiness or lethargy
  • Hairloss


  • Loss of appetite
  • Itching
  • Seizures
  • Vomiting
  • Diarrhea
  • Lethargy

Winner: NexGard

NexGard is the product I would likely recommend for most situations.

I chose NexGard vs Seresto after comparing key features:

Which is Safest?

They both have risks. The risks of using NexGard with dogs who are prone to seizures is higher.

However, NexGard is safer than Seresto when used around other family members.

Related: Are Flea Collars Safe for Dogs?

Which Works Fastest?

NexGard kicks in faster than Seresto and starts killing fleas within 4 hours versus Seresto, which takes up to 24 hours.

Which is the Cheapest?

Seresto is significantly less expensive, being than half the cost of NexGard.

Which Lasts Longer?

Seresto lasts between 6-8 months, and NexGard lasts one month.

Standout Features

Seresto lasts a lot longer, works as a preventative as well as managing fleas and ticks, while NexGard kills three different types of mites and is easy to administer.


I am partial to chewable flea and tick products over collars.

I think flea and tick collars are great, but they are not my first choice, mainly because I have a multi-pet household and because my dogs are allowed on the furniture.

That being said, Seresto is the best choice in some situations.

Use Seresto if:

  • Your dog is prone to seizures
  • You have a single dog household with older kids
  • You are looking for an effective economical flea and tick option

Use NexGard if:

  • You have a multi-dog household, or have young children who may come in contact with your dog’s collar
  • Your dog currently has fleas
  • Your dog has issues with mites

Overall, both products are excellent choices for protecting against fleas and ticks, yet when choosing between Seresto vs NexGard, a lot depends on your dog and lifestyle.


Can You Use Seresto and Nexgard Together?

Yes, the two products are effective when used together.

Though they are considered safe to use together, it is always best to check with your vet first.


Seresto Collar vs Nexgard Chewables Flea Medication for Dogs - Pinterest

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