Capstar vs Capguard: What (Woof) Is The Difference?

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capstar vs capguard

Fleas! Just the thought of them can make even the toughest pet parent shudder a little. These pesky parasites can terrorize any pets, even indoor-only cats!

Once you’ve diagnosed your pooch with a case of the creepy crawlies you need to choose an effective treatment and that’s where FluentWoof has your back.

In this review, we compare Capstar vs Capguard to find out how these products work, how to administer them to your pup, and the most important question – Do they kill actually kill fleas and protect your pooch?!

What Do Capstar and Capguard  do?

What Do Capstar and Capguard  do

Both Capguard and Capstar contain the active ingredient nitenpyram. This is a very fast-acting flea treatment that targets adult fleas. Capstar is the ‘original’ or brand-name product containing this active ingredient while Capguard is considered the ‘generic’ form.

Capstar For Dogs

Capstar contains the same active ingredient (nitenpyram) as Capguard and is generally considered the “brand-name” of this medication.


Available as tablets for oral administration, you can either “pill” your pet if they tolerate this or you can mix it with their favorite treat to ensure they eat it all.

What does it kill?

Capstar contains nitenpyram as the active medication which kills adult fleas.

How does it work?

These oral tablets are digested and the active ingredient, nitenpyram absorbed through the lining of your pooch’s small intestine into their bloodstream and around their body. Once an adult flea bites, they ingest this ingredient which kills them through it’s action on their nervous system.

How long does it last?

Short-acting, Capstar’s active ingredient remains in the body for up to 24 hours after administration.

Active Ingredient

Nitenpyram, this drug kills adult fleas before they’ve had the opportunity to lay eggs in your pooch’s fur.

How Are the Ingredients in Capstar Delivered?

As an oral medication the medication is distributed through your pet’s body and fleas need to bite in order to be exposed and killed. Nitenpyram targets nerve signaling in the flea’s body causing death.

How long does it take for Capstar to start working?

Capstar gets to work within 30 minutes of administration. Just one tablet can kill over 90% of fleas within 4 hours on your pooch.

Safety, Risks, and Possible Side Effects of Capstar

There are risks with all products and Capstar is no different in this way, though luckily adverse effects are rare and short-lived. This is in part due to the short duration of action of nitenpyram which is eliminated from your pet’s system in 24 hours. Side effects include lethargy, tummy upsets, and possibly some neurological signs though these are exceptionally rare.

What we like about it 

  1. Suitable for puppies just 2lbs and 4 weeks old
  2. Fast-acting within just 30 minutes
  3. Can kill over 90% of fleas within just 4 hours

What we don’t like about it  

  1. Fleas need to bite your pet in order to be exposed to the product
  2. The short duration of action means you need to give a tablet daily for complete protection

Our Rating:  3 out of 5! Capstar is a great product if you need an extra top-up to your usual parasite protocol for your pooch but some pets refuse to take tablets even hidden in their favorite treats which can make it difficult if you need to give the medication daily. It’s excellent for small puppies just 4 weeks old if you discover fleas. Once the pup is over 2lbs weight you can give them this medication to kill any fleas they may have as flea infestations in puppies can be life-threatening.

As always, any pet can suffer an adverse effect from medication so you should speak with your veterinarian before trying any new flea treatment for your fur-baby. This is particularly important if your pet has any health concerns or takes any regular medications. If your pet suffers a reaction then you should contact your veterinary surgery as soon as possible. 

Capguard For Dogs Review

Capguard For Dogs

Capguard contains nitenpyram in an oral formulation to kill adult fleas within just 1 hour of administration.


Easily administered, Capguard is available in tablet form.

What does it kill?

Capguard contains nitenpyram, a medication that kills adult fleas.

How does it work?

The active ingredient nitenpyram is absorbed through your pet’s intestinal lining where it’s distributed throughout their bloodstream. Once fleas bite your pet, they ingest the active ingredient targeting their nervous system and killing them.

How long does it last?

Capguard lasts up to 24 hours in your pet’s body.

Active Ingredient

Nitenpyram – This ingredient targets adult fleas before they have a chance to lay eggs.

How Are the Ingredients in Capguard Delivered?

As an oral medication, Capguard is absorbed through your pooch’s small intestine into their bloodstream and throughout your pet’s body.

How long does it take for Capguard to start working?

Capguard starts to work within just 30 minutes with 90% of fleas killed in just 4-6 hours.

Safety, Risks, and Possible Side Effects

Adverse effects to nitenpyram are thankfully rare and tend to be mild and short-lived as Capguard persists in the body for just 24 hours.

Some reported side effects are lethargy, vomiting, diarrhea, drooling, and restlessness. While seizures and incoordination are possible, these are exceptionally rare.

What we like about it

  1. Great for one-off treatments
  2. Superfast acting within just 30 minutes
  3. If your pet suffers an adverse reaction the drug is gone from their system in 24 hours.

What we don’t like about it 

  1. Short-acting at just 24 hours.

Our Rating:  3 out of 5! Capguard is a great product if your pet has just been exposed to a high flea burden and have possibly missed their usual preventative dose or for some pawrents that are concerned about pharmaceuticals in their fur-babies bodies.

The main concern is the very short duration of action at just 24 hours which means that you need to give your pet a tablet daily to ensure complete protection against fleas. This product only protects pets against fleas and not other pesky parasites such as ticks.

Capstar vs Capguard: What Are the Differences?

There are no significant differences between Capguard and Capstar products. The preservatives and “filler” ingredients may be different but these are inert substances that have no action on your pet. 

Capstar and Capguard Similarities

Active ingredient: Both products contain nitenpyram as the sole active ingredient to rid your precious pup of fleas. 

Oral administration: Capstar and Capguard are both available as oral tablets to give your pet.

Concentrations of medication: These products are available in the same concentrations of active ingredient, nitenpyram. 

Capstar and Capguard: Effectiveness

The active ingredient, nitenpyram is in both of these products and is an effective flea treatment. While they can be administered daily to protect your pet from flea infestations. it’s recommended to use a longer-acting product for prevention. 

Capstar and Capguard:  Which Is Safer?

Both of these products are safe with no safety recalls for either product. As they both contain the same concentrations of active ingredient you can give your pet the same tablet from either brand as needed. Both products are safe enough to be given to puppies as young as just 4 weeks of age once they weigh over 2lbs.

Ease of Use

As oral tablets, their ease of use depends on how good your pet is with tablets. Neither of these tablets are flavored or chewable so you need to either “pill” your pet or hide the medicine in their favorite treat. If your fur-baby is super fussy or absolutely will not take any form of tablet then these may not be the products for you. Coupled with needing to be administered daily as required, this can cause a lot of stress in some homes.

Which Scores Better on Price?

Both Capstar and Capguard cost approximately $5 per tablet so there’s no real winner on price.

Does My Dog Really Need Flea & Tick Medication?

Yes, if you’ve read other flea and tick medication reviews you’re probably well aware of the risks of these pesky parasites. Fleas in particular, can be a trigger for allergic skin reactions in some pets, and these pets need medication to prevent even just a single flea bite or a rapid treatment if they do become infested with these critters.

Capguard and Capstar aren’t the best products on the market for pets with flea allergy dermatitis (FAD) but they can provide an extra layer of protection or treatment to some pooches. Also, neither of these products kill ticks!


Q: Can I use Capguard or Capstar more than once a month?
A: Yes, both of these products can be given up to once per day as required to give your pooch relief from flea bites.

Q: Do fleas and ticks have to bite my pet for Capguard or Capstar to work?
A: Yes, as these products are oral, the drug is within your pet’s body and fleas need to bite in order to ingest the active ingredient. Neither of these products targets ticks so you will need to use a different product for ticks.

Q: My puppy is only a few weeks old. Can I still use Capguard Or Capstar? 
A: Yes, once your puppy weighs 2lbs or more and is at least 4 weeks old you can administer either of these products.

Q: My Dog is pregnant/ Nursing. Can I still use one of these medications? 
A: Neither of these products should be used in lactating or pregnant bitches as there is a small risk of birth defects or loss of puppies.

Q: Can I Combine Flea Treatments?
A: While you should never combine flea treatments without discussing with your veterinarian first to ensure safety, these products are suitable to be used with most flea preventatives if your pet still gets a flea infestation despite protection.

Q: Is This Product a Child Safe?
A: All veterinary products should be kept out of reach of children as they are not for human use. The risks of adverse effects are low but if your child eats a tablet you should contact your physician immediately.

Capstar vs Capguard Final Thoughts

Capstar vs Capguard Final Thoughts

There’s not a huge difference between either of these flea treatment products, both are similar prices and contain the exact same concentrations of the same active ingredient, nitenpyram.

Choosing between Capstar vs Capguard will depend on how you feel about ‘generic vs brand’ medications.

Generic products must contain the same active ingredient in a similar concentration to the brand-name product and Capguard meets this requirement and matches Capstar in both onset and duration of action.

Either one of these products can be used to provide fast relief and killing power against active flea infestations in your pet but they are cumbersome to use as preventative due to the need to administer a tablet every 24 hours.

Photo of author
Since graduating from Dublin, Ireland in 2013 with an honors Veterinary Medicine degree, Edele has enjoyed working with as many species of animal as possible. Edele is currently working in clinical practice while studying towards Advanced Practitioner status with the RCVS in the UK. Passionate about education and writing, Edele’s goal is to maximize the pet-owner bond and welfare through education accessible to everyone. Never found without her middle-aged Weimaraner, Purdy (who still thinks she’s 18 months old), Edele spends her limited time outdoors with her horses, hiking and traveling home to Ireland to spend time with family.

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