K9 Advantix II vs. Frontline Plus: Review of the Industry Giants


Welcome to our “K9 Advantix II vs. Frontline Plus” comparison page. Please note that this page features a review of these two top-end products. If you are looking for a comparison review of the more economical and less potent version of these flea control products, you can visit our “Advantix vs. Frontline” page.

EDITORS NOTE: Many of our readers who are looking for our price comparison chart of the leading flea treatments (e.g. K9 Advantix II vs. Frontline Plus) for cats and dogs.

Finding the best flea treatment for dogs can be a very frustrating experience. K9 Advantix II and Frontline Plus are the two most dominant names in this flea and tick control space. Therefore, it is only logical that we compare the two so that you can find out what the differences between Advantix and Frontline are and whether or not those differences are important to you and your family.

Differences between Advantix II & Frontline Plus

Both brands are very similar in that they are effective against fleas, flea eggs, flea larvae and lice for 30 days per application of the spot-on topical treatment. There are a few primary differences between these two brands. Because Advantix II has completely different active ingredients in its formula they have the following added benefits:

  • Greater Killing and Repelling Power
    • Repels fleas and ticks to decrease flea bites and disease transmission in addition to killing them
    • Repels and kills mosquitoes
    • Repels biting flies
    • More Harmful to Cats
      • Recommends 24-hour separation between dog and cats

If biting flies or mosquitoes are not a big concern in your area, or you only experience mosquito issues during specific times of the year, these added benefits may not offset the inconvenience of having to separate your dog from your cat (if you are a cat owner) for a 24-hour period.

Personally, I find the benefits of added protection against mosquitoes that may possibly be carrying the West Nile Virus or the heartworm disease to outweigh these concerns. Bayer states:

Repellency helps prevent ticks, fleas, and mosquitos from attaching, biting or feeding. A repelled parasite doesn’t bit or attach. If it doesn’t bit or attach, it can’t transmit the organisms that may cause disease.

Additional Differences

There are a few other differences between these brands. They have different weight classifications so you must be careful when switching between the brands to ensure that you buy the correct dosage and do not harm your pet. Additionally, Bayer recommends the application of its treatment in multiple areas of your animals back to speed of the translocation (spreading) of the medicine across its entire body.

Bayer states that you can apply Advantix II on puppies starting at 7 weeks, which is slightly earlier than Frontline Plus’ warning label stating that puppies should be at least 8 weeks. Although this could in some ways give a slight advantage to Bayer’s Advantix II, the fact is most states do not allow breeders to sell puppies until they are 8 weeks old. So, unless you are a breeder this distinction between the two brands is irrelevant and should not be a factor in your decision to purchase one over the other.

Effectiveness Against Fleas

Based on packaging and label information, and online literature available at their respective websites, Frontline Plus seems to have a performance advantage when it comes to killing adult fleas. Frontline Plus states that it starts killing fleas within 4 hours of application and will kill 100 percent of adult fleas within 12 hours. Advantix II does not specify when its medication begins to kills fleas and simply states that within 12 hours it will kill 100 percent of the adult fleas.

It is odd that Bayer’s packaging and literature do not communicate this point. So, if speed of effectiveness is a deciding factor you may want to lean towards Frontline Plus or other brands that even work faster (e.g. Parastar Plus, Sentry FiproGuard Max , etc.)

Effectiveness Against Ticks

Both products kill ticks with neither companies really articulating anything substantive on the subject of how fast it starts to kill them.

Effectiveness against Mosquitoes and Biting Flies

The K9 Advantix II formula contains permethrin and imidacloprid. When these two chemicals are combined it makes both of them even more effective killers of insects and pests. It is in the area of mosquitoes and biting flies that Advantix really differentiates itself from Frontline Plus. Bayer literature states that their product kills up to 98.3% of mosquitoes and reduces their blood feeding by more than 95%.

Pricing Comparisons

Both products fluctuate dramatically in price based on the retailer and whatever promotion is being run by the vendor or manufacturer. Personally, I have yet to see an instance where you save money buying the product in the store. It has always been cheaper to find both brands online from my personal experience.

My Recommendations

Without question, K9 Advantix II is the superior product. But, does that mean it is the right product for you?

Here are my recommendations in the K9 Advantix II vs. Frontline Plus battle:

  1. If mosquitoes and biting flies are a big issue where you live or during the current time of year, I would choose K9 Advantix II.
  2. If I owned a cat that physically interacts with my dog, (especially if I have a puppy) and mosquitoes and biting flies are a big issue, I would still opt for Advantix and just make sure that I keep my cat separated from my dog(s).
  3. If I owned a cat and wasn’t really concerned about mosquitoes or biting flies, I would probably opt for Frontline Plus (especially if it is on sale or priced significantly lower than Advantix).
  4. If my dog and I spent a lot of time in the outdoors on hikes, in woodlands or expansive grassy areas, I would select Advantix.
  5. If my dog is confined to the house and/or I live in a more urban area without much exposure to wooded areas, I would feel comfortable with Frontline Plus (unless it was priced significantly higher than Advantix).
  6. If I have consistently used Advantix or Frontline on my dog for a year or more, I would switch products and mix it up just for the sake of preventing fleas from becoming tolerant/immune to the products. There have been reviews of Frontline (which is the most popular treatment) where pet owners claim that the product seems to be losing its effectiveness and killing strength.
  7. Use the links below to buy the flea treatment that is right for you and your dog below. Trust me, it is much cheaper than walking into the store and getting hosed.

One final note. We have spent some time in other places on this website discussing the importance of inactive ingredients and how humans and animals may react differently to similar drugs due to how their body reacts to these ingredients. It is quite possible that your dog may react completely differently to one of these products versus another similar dog. If you are using either of these products and do not feel that you are experiencing the desired results, give the other one a shot and see if you like it better.