Advantage vs. Advantage II: What is the difference?


Many people often ask what the differences between Advantage and Advantage II are so we have put together a comparison page so that you can easily understand the differences. If you are looking for a listing of all our flea and tick control spot-on product reviews, you can find it here.

Bayer, the German corporation that manufactures K9 Advantix, produces the Bayer Advantage line of flea and tick control products for cats and dogs. Similar to the roll out of K9 Advantix, Bayer introduced Advantage II as a successor to their original Advantage formula.

The original Advantage formula no longer seems to be institutionally supported by Bayer as evidenced by its omission from this list. Somewhat confusingly, the company has elected to continue the use of the Advantage name sans the “II” for their multi-formula product which is geared towards heartworm and other diseases.

The Original Advantage Formula

The key distinction between the Bayer Advantage line of products and their K9 Advantix offerings is that Advantage DOES NOT kill ticks. Hence, the blending of Advantage and “ticks” to form the more robust name Advantix.

The original Advantage formula only contained imidacloprid. Imidacloprid kills adult fleas and has some effect on flea larvae, but it did not kill flea eggs. Advantage II is infused with the insect growth regulating chemical called pyriproxyfen. Pyriproxyfen artificially maintains elevated levels of the juvenile growth hormone in flea eggs and this prevents the eggs from hatching.

My Recommendations

Advantage vs. Advantage II: The winner is Advantage II.

The original formula, if you can even find it, is an inferior product that does not kill fleas throughout their entire lifecycle. I hope this information has helped you to better understand the factors one must consider when determining which flea treatment for their dog is best.


To read reviews and comparisons of Advantage versus other brands and formulas, please see below:

Advantage vs. Frontline

Advantage II vs. Frontline

Advantage II vs. Frontline Plus