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Frontline vs. K9 Advantix Flea Treatment: Which Is Better?

Nicole Cosgrove Profile Picture

By Nicole Cosgrove


Review Summary

One of the most important things you can do for your dog is to give them a regular flea treatment. In addition to sparing them from the discomfort and irritation that the little biting insects can cause, an effective flea treatment can also keep certain diseases at bay.

But how are you supposed to know which flea treatments are effective? After all, there are quite a few out there, ranging from all-natural options to those that use powerful pesticides. Is one really better than another?

Let’s look at two of the top flea treatments on the market today, Frontline and K9 Advantix, to see which one we’d recommend for your dog. Ultimately, we found that Frontline is a little better at eliminating an existing flea problem, whereas K9 Advantix helps prevent one before it starts.

However, both are still excellent overall, and you can’t go wrong with either one. K9 Advantix is usually a bit cheaper, though, which may serve as an effective tiebreaker.

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A Sneak Peek at the Winner: Frontline Plus

Rating Image Product Details
Best Overall
Frontline Plus Frontline Plus
  • Extremely effective at killing fleas
  • Safe for pregnant or nursing dogs
  • Works well at low doses
  • Runner-Up
    Second place
    K9 Advantix K9 Advantix
  • Kills and repels fleas and other pests
  • Also works on mosquitoes
  • A bit less expensive than Frontline
  • What Are the Differences Between Them?

    As noted above, both treatments are similar in terms of effectiveness, but that doesn’t mean that they’re identical. In fact, they have several key differences, as we’ll highlight below.

    Method of Application

    Both are topical treatments, so you simply break open the container and rub the fluid directly on the dog’s skin. It then absorbs through the skin into the bloodstream, so any flea that bites your pup will die as a result.

    Frontline is a bit easier to put on, as you only have to apply it to a single spot directly between the shoulder blades. If your dog weighs more than 20 pounds, you’ll have to apply K9 Advantix in two spots: between the shoulder blades and at the base of the tail.

    This isn’t a huge deal, but if you have a squirmy dog who absolutely hates the flea treatment for some reason, you might prefer to only have to apply it one time.

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    Active Ingredients

    Both use pesticides to kill fleas. Frontline’s active ingredients are Fipronil and (S)Methoprene, whereas K9 Advantix uses Imidacloprid, Permethrin, and Pyriproxyfen.

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    How effective are they against fleas?

    Generally speaking, Fipronil (the active ingredient in Frontline) has been shown to be a bit more effective at killing fleas than the ingredients in K9 Advantix. Fipronil also requires lower dosages to be effective, which may be appealing to owners who aren’t crazy about rubbing chemicals on their pet’s skin.

    Frontline doesn’t repel fleas at all, so K9 Advantix wins this by default.

    To be fair, Frontline kills the insects so quickly that its lack of deterrent isn’t a huge issue, but if you want to spare your pooch even the slightest discomfort, K9 Advantix may be the better choice.

    What about other insects?

    Both are effective at killing ticks, and Frontline is probably superior in that regard. However, only K9 Advantix repels them.

    One big difference between the two is that K9 Advantix also kills and repels mosquitoes, whereas Frontline makes no claims as to being effective in that regard.

    Which product is safer?

    Both have been shown to be completely safe for dogs, although Frontline is probably safer for pregnant or nursing animals (consult your vet before giving a pregnant dog K9 Advantix). Also, both can potentially cause skin irritation, so be sure to monitor your dog after application.

    However, if you have cats, you should never apply K9 Advantix to their skin, as one of its active ingredients, Permethrin, is toxic to felines.

    Which product is cheaper?

    K9 Advantix tends to be a bit less expensive than Frontline, although the difference is marginal, usually only a few bucks or so. The price difference will vary depending on where you buy your flea treatments as well.

    Which product lasts longer?

    Both are designed to last for one month after application. Both are also waterproof once they’ve been absorbed into the skin, so you can bathe your dog or let them take a dip in the pool without compromising the medicine’s effectiveness.

    divider 9

    Quick Rundown of Frontline:

    Frontline Plus Flea & Tick Large Breed Dog Treatment, 45 - 88 lbs

    Frontline is one of the most popular flea treatments out there, and you can buy it in pet stores and big-box stores, as well as from your vet.

    • Extremely effective at killing fleas
    • Safe for pregnant or nursing dogs
    • Works well at low doses
    • Doesn’t repel fleas or ticks
    • Not effective against mosquitoes

    Quick Rundown of K9 Advantix:

    k9 advantix

    K9 Advantix shouldn’t be confused with K9 Advantage, which is made by the same manufacturer. K9 Advantage is a budget version that’s significantly less effective.

    • Kills and repels fleas and other pests
    • Also works on mosquitoes
    • A bit less expensive than Frontline
    • Not as effective at killing fleas
    • Toxic to cats

    divider 10What the Users Say

    Given that these are two of the most popular flea treatments on the market today, there’s no shortage of feedback from users, both good and bad.

    One of the biggest differences we discovered between the two products is the demographics of the users. K9 Advantix enjoys strong support in rural areas, where dogs are often left outdoors and repelling mosquitoes and other flying insects is extremely important.

    City dwellers tend to prefer Frontline, however, as their pets are often kept indoors most of the time, so there’s less need to protect them from bugs.

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    Many users also feel that Frontline is extremely good at one thing — namely, killing fleas — whereas K9 Advantix is less effective in that regard but better as an overall pest treatment.

    Ultimately, however, both should generally be effective at keeping your dog safe. It just comes down to your specific needs: If your dog is often left exposed outdoors, then you’ll appreciate the all-around protection that K9 Advantix offers. If you just want any existing fleas to die as quickly as possible, Frontline is likely your best bet.

    Fortunately, there’s not really a wrong answer here.

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    Frontline or Advantix: Which Should You Choose?

    Frontline and K9 Advantix are both effective flea treatments, and which one is better for your dog will likely depend on your specific needs. K9 Advantix is the more versatile of the two, whereas Frontline is more potent and will likely clear out existing infestations faster.

    Generally speaking, owners whose dogs spend a great deal time outdoors will be better off with K9 Advantix, whereas those who keep their dogs inside may prefer to use Frontline.

    The good news is that you’re not going to make a mistake buying either product. As long as you use them consistently and correctly, both Frontline and K9 Advantix should keep your dog safe from those pesky parasites.

    Further reading

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