K9 Advantix II Flea & Tick Treatment

Name: K9 Advantix II Flea & Tick Treatment (2-Mo)
Brand: K9 Advantix
SKU: B00I2266Y2
Availability: InStock
Rating: 4.4 (33653 reviews)

Words · Craig & Sammy · ASIN B00I2266Y2 · Filed under Flea & Tick Prevention

“High volume product, high volume of complaints. It works for most dogs most of the time, but Sammy's small enough that I'd need to watch the dosing carefully — medium is 11–20 lbs, and he's barely 3.2 kg. Vet-check before first application.”

Yorkies love outdoor adventures, but fleas, ticks, and mosquitoes can turn a pleasant walk into a health hazard for your tiny companion. K9 Advantix II provides vet-recommended triple protection that kills and repels these pests on contact, so they do not even have to bite your precious pup. This is particularly important for Yorkies since their small bodies (typically 4-7 lbs) are more susceptible to flea-borne anemia and tick diseases. While this formula is sized for medium dogs (11-20 lbs), consult your veterinarian about proper dosing for your Yorkie. The waterproof formula keeps working after baths and swimming, and this convenient 2-month supply means fewer trips to the store.

Application is simple - just part the fur between the shoulder blades and apply directly to skin. The fast-acting formula starts killing fleas within 12 hours and provides month-long protection. Keep your adventurous Yorkie safe from parasites while enjoying every outdoor moment together. Check the price on Amazon today.

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The Notes

Sizing: Sized for Yorkies 4–7 lb · check the printed chest measurement
Source: Amazon · ASIN B00I2266Y2
Filed: Flea & Tick Prevention
Brand: K9 Advantix
Reviews: 4.4 · 33653 ratings
Verdict: Worth it

What owners loved

+ Ease of application is near-universal: 161 of 165 users say it's simple to apply to the back of the neck with clear directions
+ When it works, it delivers: 641 of 1013 flea reduction reviews confirm complete flea clearance and freedom from scratching
+ Better value than vet-purchased alternatives like Frontline: 336 of 549 value reviews note it's cheaper and arrives at your door

Watch for

− Effectiveness is genuinely mixed: 711 of 1955 effectiveness reviews report it doesn't work at all, with dogs still infested after application
− Side effects are a real concern: 290 of 446 side-effect reviews report itching, skin irritation, sores, or systemic reactions (vomiting, diarrhea) around the application site
− Longevity falls short of claims: 68 of 120 longevity reviews say it wears off before 30 days (some users report 3 weeks or less)

What owners say

From the reviews.

K9 Advantix II has strong fundamentals—application is straightforward and when it works, owners are satisfied—but the data shows significant hit-or-miss efficacy. Nearly 36% of effectiveness reviews are negative, and side effects appear in roughly 65% of all side-effect commentary. The product works reliably for some dogs in some climates, but fails or causes reactions in enough cases that users should vet it with their dog's history and local parasite pressure before committing to a bulk pack.

Source · 33653 verified Amazon reviews · Average 4.4 stars

Customer questions

Things people ask.

Q01. Does K9 Advantix II actually kill fleas, or just repel them? +

It's supposed to kill them, but results vary sharply. Of 1955 effectiveness reviews, 1244 are positive—but 711 are negative, with users reporting fleas still present after application. Some users report it works for years; others say it fails within weeks. Geography and flea pressure seem to matter: users in hot, humid areas report more failures.

Q02. How long does each application actually last? +

The label says 30 days, but 68 of 120 longevity reviews report it wears off early—typically between 21–25 days. A smaller number report it lasts longer, especially in cooler weather. You may need to reapply before the month is up.

Q03. Will it cause skin irritation or side effects on my dog? +

For many dogs, no. But side effects are notable: 290 of 446 side-effect reviews mention itching, redness, scabs, or systemic issues like vomiting and diarrhea. 156 reviews report no adverse effects at all. Reaction seems to depend on individual sensitivity; some dogs tolerate it fine, others develop weeping sores.

Q04. Is it cheaper than buying from a vet or pet store? +

Yes, consistently. 336 of 549 value reviews confirm Amazon pricing is lower than PetSmart, Frontline, or vet-dispensed alternatives. Users cite it as the main reason they buy in bulk here rather than in-store.

Q05. Is this safe to use on smaller dogs or puppies? +

The product is labeled for dogs 11–20 lbs (medium). The scraped data doesn't include reviews from toy or tiny breed owners, so application safety on dogs much smaller than 11 lbs is unclear. Consult your vet before using on Yorkies or other small breeds under label weight.

The verdict