Let’s Compare K9 Advantix II and Frontline Plus Flea and Tick Control Products

Widely considered to be the top two flea and tick control medications on the market, I decided to compare K9 K9 Advantix II vs Frontline PlusAdvantix II and Frontline Plus in order to help determine which flea medicine is a better choice. By researching and compiling authoritative information from users and trusted sources, I’ve come up with a definitive comparison of these top flea and tick killers.

This chart compares claims about the effectiveness against different types of pests:

 K9 Advantix IIFrontline Plus
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Kills FleasYesYes
Repels FleasYes
Kills TicksYesYes
Repels TicksYes
Kills Flea Eggs & LarvaeYesYes
Kills LiceYesYes
Repels & Kills MosquitoesYes
Repels Biting & Stable FliesYes
Repels & Kills Sand FliesYes

The written comparison below focuses on the following similarities and differences:

  • Active ingredients, how they work, what parasites and/or pests they kill or control
  • How to use, how to apply
  • Risks, adverse reactions, tips for households with cats
  • Availability and package contents, dosages, pricing considerations, best price

Active Ingredients and How They Work

Both of these treatments are highly effective at killing fleas and ticks, but when comparing the active ingredients, there are some notable differences. Frontline Plus contains two active ingredients, Fipronil (9.8%) and (S)-Methoprene (8.8%) which cause fleas to die within 12 hours of application and ticks within 48 hours. When you apply Frontline to your pet’s skin, fipronil is stored in the oil glands. From there it is distributed evenly through the hair follicles through a process called translocation. Fleas and ticks do not have to bite your pet first in order to die, just coming into contact with your pet’s hair coat is enough to kill them. Fipronil also breaks the flea’s life cycle in all stages, which helps prevent future infestations. It is highly effective in killing fleas, ticks, and biting lice. If you only need to protect against fleas and ticks, then Frontline Plus is an excellent option.

Note about Bayer products:

Bayer manufactures two similar products, K9 Advantix and K9 Advantix II, which are almost identical. The only difference is that K9 Advantix II, the newer version, adds an insect growth regulator called pyriproxyfen. This new ingredient kills flea eggs and flea larvae. It has all the previous ingredients from the old formula; it just adds the extra ingredient pyriproxyfen to make it a complete flea killer. More info on regular K9 Advantix Vs K9 Advantix II here.

K9 Advantix II has 3 notably different active ingredients and a mysterious blend of “unspecified” ingredients. It contains Imidacloprid (8.80%), Permethrin (44.0%), Pyriproxyfen (0.44%), and “Other Ingredients” (46.76%). What are those “other ingredients?” Unfortunately, Bayer does not disclose what they are. So, focusing on what we do know, the ingredients in this product do more than just kill fleas and ticks.

The new version’s improvement over the original product is the addition of the insect growth regulator, (IGR) called pyriproxyfen, which kills flea eggs and flea larvae. In addition, the new formula still has imidacloprid and permethrin to kill fleas, ticks, mosquitoes and biting lice. The blend of ingredients is also designed to repel pests before they can bite your pet. In addition to killing all the pests I just mentioned; it also repels them before they can get to your pet. Biting flies are the only pest mentioned that the formula repels but does not kill. Advantix was designed to be more of a complete solution to parasite problems and may be an excellent option for pet owners who live in areas where these types of pests thrive.

How To Apply

Application: Both of these flea treatments are applied topically. The applicator tubes contain liquid (flea drops), all you have to do is apply the contents of one applicator tube to your pet’s skin, while your pet is standing, between the shoulder blades on their back. The instructions from Bayer?are slightly different only because they recommend they you apply the contents of the applicator tube to 2-4 different spots on your pet’s back, from the shoulder blades down to the base of the tail. Frontline’s instructions are to apply the entire tube to one spot between the shoulder blades.

Risks, Adverse Reactions, And Considerations For Households With Cats

K-9 Advantix products should never be used on cats. It is extremely poisonous to cats and can even kill them if they are overly exposed. The reason is that cats are unable to metabolize certain compounds like permethrin. If you have cats in your household, then it is recommended that you separate your cat and dog at least until the medication has dried. This time can vary, so you may want to separate them for 12-24 hours to be completely safe.

Frontline Plus does not have as many warnings about side effects or adverse reactions, but it some cases it can cause skin irritation at the site of application. The irritation should go away within a couple of days, but if it becomes worse within a few days, then go see your veterinarian. In regards to cats, you should not use “Frontline for dogs” on a cat because the dosages and ingredient content are different for the cats. That said, it is not necessary to separate your dogs and cats when you treat one or the other. I personally do not separate my cats when treating my dogs, and I’ve never had a problem.

Adverse Reactions Warning: There are many reports of adverse reactions from both of these products. The fact is, adverse reactions are going to happen to a small percentage of dogs with any flea treatment. Comparing adverse reactions of Advantix and Frontline, they are about the same and may include irritation at the application site, loss of appetite, nervous or strange behavior, and restlessness. Most problems occur due to dosage mistakes by the pet owner. Just make sure the follow the directions closely to reduce any chance of side effects.

For those of you who are put off by the potential side effects of chemically based products like Advantix and Frontline, there have been some good reviews about this natural flea and tick control product called Pet EasyDefense Flea and Tick Tag by Only Natural Pet. This may be a good option for naturally inclined pet owners.

Availability, Package Contents, And Pricing Considerations

K9 Advantix II is available in 4 pack, 6 pack, and 12 pack. Each package contains 4, 6, or 12 applicators. Each applicator contains one dose and is to be applied to your pet once per month. The product is sold according to your dog’s weight:

  • Dogs up to 10 Lbs. (Green)
  • Dogs from 11-20 Lbs. (Teal)
  • Dogs from 21-55 Lbs. (Red)
  • Dogs weighing over 55 Lbs. (Blue)

Frontline Plus is available in 3 pack, 6 pack, and 12 pack. Each dose, one applicator, lasts one month. The product is also sold according to your dog’s weight:

  • Dogs and puppies (8 weeks and older) up to 22 Lbs.
  • Dogs from 23-44 Lbs.
  • Dogs from 45-88 Lbs.
  • Dogs from 89-132 Lbs.

Note: When comparing ?prices, keep in mind that the smallest package offered for Frontline only has 3 doses, whereas the smallest package for Advantix has 4 doses. Comparing prices on 6 packs and 12 packs are more straight forward because you are getting the same dosage in both packages.

In Summary, Which Is A Better Value?

Well, it depends on how you look at it. If you live in an area where fleas and ticks are a more serious problem than flies and mosquitoes, then you can trust Frontline Plus will do the job. It’s a very effective product; I use it on my 3 dogs and have never had a problem with it. I also have two cats in the house that have never been negatively affected by our dogs’ treatments. When you consider K9 Advantix’s potential for hurting cats, that can be a decisive factor. You will need to make sure your dogs and cats are separated for 12-24 hours if you decide to use Advantix in a household with cats.

Frontline Plus is widely available online at some pretty cheap prices. If buying online, it’s generally a better value to go with the 6 pack or 12 pack if you are looking to save money. There’s no sense paying more at the vet or pet store for the same exact product you can get cheaper online and have it mailed to your house. See my low price recommendation below.

K9 Advantix II is an excellent choice for people who live in areas with lots of mosquitoes and flies. If you see your dog being bothered by flying pests, then chances are you live in an area where K9 Advantix II can be your dog’s best friend. Does your dog live outside or spend a considerable amount of time outside? If so, I recommend trying K9 Advantix II. It kills fleas and ticks and can help control pesky flying bugs. I have used it on my dogs and was very happy with the results. I started using Advantix before I ever tried Frontline and I never had a problem with fleas and ticks, nor mosquitoes and flies. Eventually though, I decided to try Frontline because I found it cheaper than K9 Advantix and I found that it worked just the same. Also, I have cats in the house so that was really a deciding factor on why I use Frontline now. If I didn’t have cats then I would still be using Advantix.

Where To Buy – Recommended Sources:

Check Price - K9 Advantix II

Frontline Plus Lowest Price 2019


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