GiarCidia Defender – Oral Flea Treatment for Dogs and Cats

FleasDogs and catsMade in the USA

Defender

Liquid flea treatment · dogs and cats

$39.99 $49.99

Made for fleas in dogs and cats: nitenpyram 50 mg per ml.
Once a day for 7 days, then twice a week as needed.
A milk-flavored liquid, so there's no pill to hide.

How much does my pet need? Work it out by weight

Purchase option Subscribe & Save 10%$35.99every orderKeep a bottle on hand for the next course.

10% off every order
Ships every month
Pause, skip or cancel anytime

One-time purchase$39.99

Secure checkout · Free shipping over $70

Often used together

TapewormPrazi for Dogs $39.99

TapewormPrazi for Cats $39.99

6 types of wormsZap-Wormer $58.99

What is it for?

Fleas in dogs and cats.

How do I give it?

Shake well. Measure 0.1 ml per lb with the syringe and give it by mouth or in food, once a day for 7 days, then twice a week as needed.

Why pair it with Prazi?

Fleas spread tapeworm. If you spot rice-like bits near the tail, treat tapeworm too.

Do I need a prescription?

No. It's sold over the counter, so you can treat at home.

Made in the USAFDA-approved facility
Dogs & catsOne formula for both
Syringe in the boxDose by weight

“Products and support are excellent! I highly recommend Giarcidia to our puppy families and fellow breeders.”

Katie Stout

Made for fleas
Dogs and cats
Once a day for 7 days
Milk flavor
Made in the USA
5.0 on Google
Free shipping over $70

Everything in the bottle. Nothing to guess.

Nitenpyram50 mg per ml, made for fleas
Milk flavorNo pill to hide

Made in the USAIn an FDA-approved facility
Treat the home tooWash bedding, vacuum often

5 stars: 23 (92%)
4 stars: 2 (8%)
3 stars: 0 (0%)
2 stars: 0 (0%)
1 star: 0 (0%)

Flea free thanks to this product !

1000% happy with this product , it works!! It's been a very bad year for you. Please and three of my dogs and two of my son's cats. All had fleas even after numerous baths and using a couple of other products. We thought it was worth a try to try this. And I am so glad that we did, because everybody is now flea free, i highly recommend this product

Life saver.

Gave this to my cat in the evening. Next morning I sat her down to comb her to see if it work ed get the dead ones and eggs off. The amount I got off was crazy. But when she got up and walked away, just the amount on the pee pad were crazy. So glad I found this. Life saver.

Giarcidia kills fleas on your pets

This product works I have tried everything to get rid of fleas on my cat I got the giarcidia today and gave it to my cat I found a dead flea on him I m so happy I will order giarcidia again I m a very happy customer

works 💪 wonders love this stuff.

Great Product

I have tried everything to get rid and control my babies fleas Until I got Giarcidia Flea Support. No more fleas. Great product and very happy with the results

It handled the fleas quickly after other products had failed. Easy to administer. I would definitely recommend!

works very wll
well saw dead fleas on them 30 min later.

Great product

Great buying experience. The product arrived quickly, well packaged, and in perfect condition. Excellent communication, reliable seller, and very professional. I’m very happy with my purchase and would definitely buy from this seller again. Highly recommended!

Finally a product that works

I was very pleased with the results from this product. I have had a hard time controlling fleas this year and found this. Whew, what a game changer. My digs and cats are now flea free. I followed the instructions could not be happier. I am so glad I found something to relieve my pets issue, they had to be miserable. I given this an10 out of 10!!

Great Alternative & Nice Price

This product did the trick, fleas are gone! Our battle with fleas is worst during August, and I am happy with this product. It works just like it’s described. Plus, it’s Made in the USA.

It works

This product really works. I will most definitely buy it again. It looks like you get it cheaper if you add it as a subscription.

Works great

Works great for our backyard buddies. Easy to dose food.

The best of the best

We A&J kennel could not recommend enough! We breed American cocker spaniels a this stuff is absolutely amazing!! Love love this company! Will never use anythjng else

It works

Worked for all the kittens and cats 🐈

Fleas beware

We bought this about a month ago and it's pretty effective on out cats and kittens. We love that it's safe to use and doesn't make our cats sick or anything. The scent is like pineapple and coconut, which makes it easier for the cats to swallow. All in all, would recommend trying it.

Killed all the fleas!

This stuff worked! Fleas were falling off my cats dead in piles! Had a infestation I needed to get under control! And this med worked quite well! Totally recommend!

This works

This is amazing 🤩 it really works. The flea stuff works too

Liquid nitenpyram

Kills adult fleas. My cats tolerate it but they don't like it. It does what it's supposed to do

Did the job!

I am so thankful I found this product. I had tried everything and was beginning to lose hope. The fleas were eradicated overnight!

puppy and kitty flea

yes it works really good for both but the price is high for just a few ounces

Love this stuff, bye bye fleas!

This stuff is amazing for my cats! my cats like their dry food with a little water to soften it, so I pour some of this into a water bottle and use that to soften their food. With multiple cats, this has been the most efficient and effective treatment I’ve found, and the fleas are almost instantly gone!

Safe on my kittens

Would buy it again

Fleamageddon

This worked so well, and within 15 minutes. The fleas just started dropping off the kittens and my cat. I knew it was bad, but wow! I am definitely happy with how fast it worked.

Mis chaparros

Exelente megatón mucho

Lo mejor

Gracias por sus buenos servicios

Measure. Give. Repeat.

AI placeholder

Step 1 Measure
0.1 ml per lb, with the syringe.
Step 27 days Give
Once a day for 7 days, then twice a week as needed.
Step 3 Treat the home
Wash bedding and vacuum while you treat.

From the label: not for puppies or kittens under 4 weeks old. Most fleas live in the home, not on the pet.

How much to give, pet by pet.

Move the slider to your pet's weight. We'll show the daily dose, the full course, and which bottle covers it.

How many?

About how heavy, on average? 20 lb

Your 20 lb dog gets

4mlonce a day

Your dog needs about 40 ml for a full 7-day course.

1 × 120 ml covers it

From the Defender label: 0.1 ml per lb (2.5 lb = 0.25 ml up to 40 lb = 4 ml; over 40 lb, combine doses), once a day for 7 days, then twice a week as needed. This shows the first 7 days.

Frank Bustos showing one of his Rottweilers

Started in a breeder's kennel.

GiarCidia Inc. was founded in February 2024 by a dedicated breeder who spent nearly a decade raising show-quality and family-oriented Rottweilers. Throughout those years, his top priority was ensuring that every puppy went home healthy, happy, and free from worms and parasites.

Like many breeders, he faced the ongoing challenges of Giardia, Coccidia, and intestinal worms, conditions that can seriously impact a puppy’s health and, in some cases, even result in loss of life. Determined to find a better solution, he made countless veterinary visits and explored various treatment options. Despite his efforts, he found no reliable protocol that consistently delivered the results he was looking for.

Rather than accepting the problem, he committed himself to finding a solution.

Read Frank's full storyShow less

After more than two years of extensive medicine research, conducting trials, evaluating results, and spending countless hours in the laboratory, Mr. Bustos developed a formula that consistently produced positive results within his own breeding program. Wanting to ensure its effectiveness beyond his own litters, he provided trial products to breeders across the United States, allowing them to test the formula with their own puppies before introducing it to the public.

The feedback was overwhelmingly positive.

Following that feedback from breeders, the formula was later expanded for use in cats as well. Throughout the development process, GiarCidia remained committed to quality and compliance, including making every product in an FDA-approved facility and following applicable FDA guidelines.

Today, our products are trusted by breeders and pet owners across the country. Our formulas are made to help treat common intestinal parasites, and we believe pet owners should have access to solutions that can be given conveniently from home, reducing unnecessary stress on both pets and their families.

Our products are manufactured with quality in mind and are available in a variety of natural flavors to make giving them easier and more enjoyable for your pets.

With customers across the USA and more than 100 five-star Google reviews, we are proud of the trust our customers place in us. Nothing is more rewarding than helping pet owners see their dogs and cats healthy, thriving, and living their best lives.

GiarCidia products were not created by someone looking to enter the pet health industry overnight. They were developed by someone who personally experienced the same challenges faced by breeders and pet owners every day. Through years of hands-on experience, research, testing, and dedication, Mr. Bustos developed solutions designed to address real-world problems and provide practical support for the health and well-being of pets everywhere.

10 yrs: Breeding Rottweilers
2+ yrs: Developing the formula
5.0: On Google, 136 reviews

Frank BustosFounder & CEO, GiarCidia

Defender vs. tablets.

A liquid you give by mouth or in food. No pill to hide, nothing to split.

LiquidNo pill to hideDogs & cats

GiarCidiaDEFENDER

Tablets

Good to know.

Before you start

0.1 ml per lb: 2.5 lb = 0.25 ml, up to 40 lb = 4 ml
Not for puppies or kittens under 4 weeks old
Shake well; store at or below 77°F
Treat every pet in the home
Wash bedding and vacuum often
Keep out of reach of children

Questions, answered.

Does Defender treat ticks?

The Defender label covers fleas.

How do I give Defender?

Once a day for 7 days, then twice a week as needed, by mouth or in food. Dose by weight: 0.1 ml per lb (2.5 lb = 0.25 ml, up to 40 lb = 4 ml). Not for puppies or kittens under 4 weeks old.

Do I need to treat the house too?

Most fleas live in the home, not on the pet. Wash bedding and vacuum often while you treat.

Can fleas cause worms?

Yes. Pets that swallow fleas can get tapeworm. Prazi is made for tapeworm.

When should I call the vet?

If the skin is broken or infected, your pet is losing hair in patches, or a young puppy or kitten has a lot of fleas.