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Choosing between NexGard and Simparica Trio is one of the most common decisions dog owners face when shopping for all-in-one flea, tick, and heartworm protection. Both are chewable, vet-grade tablets that dogs actually enjoy taking — but they differ in spectrum of coverage, active ingredients, and value. This head-to-head comparison breaks down everything you need to know so you can pick the right product with confidence.

Quick Comparison at a Glance

Before diving into the details, here's a snapshot of how these two products stack up side by side:

• NexGard (afoxolaner): Kills fleas and ticks for a full month. Does not cover heartworm or intestinal worms on its own.
• Simparica Trio (sarolaner + moxidectin + pyrantel): Kills fleas and ticks plus prevents heartworm disease and treats common intestinal worms — all in a single monthly chew.

The biggest headline difference? Simparica Trio is a true all-in-one tablet, while NexGard focuses specifically on external parasites. If you only buy NexGard, you'll still need a separate heartworm and worming product to keep your dog fully protected.

What Each Product Actually Covers

Understanding the spectrum of coverage is the most important factor when comparing NexGard to Simparica Trio. Here's the breakdown:

NexGard covers:

• Fleas (kills adult fleas before they can lay eggs)
• Multiple tick species, including paralysis ticks, brown dog ticks, and lone star ticks

Simparica Trio covers:

• Fleas (rapid kill, typically within hours)
• Multiple tick species
• Heartworm prevention
• Roundworms and hookworms

For dog owners who want comprehensive flea, tick, and heartworm defense from a single chew, Simparica Trio has the clear edge. NexGard remains an excellent option if you already have a separate heartworm preventive in place and simply need best-in-class flea and tick control.

Active Ingredients and How They Work

Both products belong to the isoxazoline family of parasiticides, which target the nervous system of fleas and ticks to deliver fast, reliable kills. The difference lies in the extras.

NexGard contains afoxolaner as its sole active ingredient. Once your dog chews the tablet, afoxolaner circulates through the bloodstream and kills fleas within eight hours and ticks within 48 hours of attachment.

Simparica Trio uses sarolaner (another isoxazoline) for fleas and ticks, combined with moxidectin for heartworm prevention and pyrantel for intestinal worms. This triple-action formula is what makes it a genuine all-in-one solution.

Both active flea and tick ingredients work systemically — meaning the parasite must bite to be exposed — so neither product repels parasites. They kill on contact with the bloodstream, which effectively breaks the lifecycle and prevents infestations from taking hold.

Palatability, Dosing, and Ease of Use

Both NexGard and Simparica Trio are beef-flavored chewable tablets designed to be given once a month. Most dogs eat them willingly as a treat, which removes the mess and stress of topical spot-on treatments.

Each product is available in weight-range-specific sizes, so you simply match the pack to your dog's current body weight. Both are approved for puppies from eight weeks of age, though minimum weight requirements differ slightly — always check the product label for the correct size.

Because the tablets are taken orally, there's no need to separate dogs after dosing or worry about the product washing off during baths or swimming. This makes monthly compliance straightforward, especially in multi-dog households.

Browse our full range of flea, tick, and worm treatments for dogs to compare pack sizes, pricing, and multi-buy deals on both products.

So Which One Should You Choose?

The "better" product depends entirely on your dog's current parasite prevention plan:

• Choose Simparica Trio if you want one chew that handles fleas, ticks, heartworm, and intestinal worms. It's the most streamlined approach and reduces the risk of gaps in protection.
• Choose NexGard if your dog is already on a heartworm preventive you're happy with and you want a dedicated, proven flea and tick killer to pair with it.

Both products are backed by extensive safety data and used by millions of dogs worldwide. Neither is objectively "better" — but Simparica Trio does offer broader coverage per tablet, which often translates to better value and simpler dosing schedules.

Cost-wise, buying a single all-in-one product like Simparica Trio is usually more economical than purchasing NexGard plus a separate heartworm preventive. Factor in the convenience savings of one chew instead of two, and the math tends to favor the triple-action option.

Frequently Asked Questions

Can I give NexGard and Simparica Trio together?

No. Both contain isoxazoline-class ingredients that target fleas and ticks, so combining them would double up on that protection unnecessarily. Choose one flea and tick product and build the rest of your prevention plan around it.

How quickly do these chewables start killing fleas?

Both products begin killing fleas within hours of ingestion, with full efficacy typically reached within 24 hours. This rapid speed of kill helps stop infestations before fleas can reproduce on your dog.

Are these products safe for puppies?

Yes. Both NexGard and Simparica Trio are approved for puppies from eight weeks of age, provided they meet the minimum weight listed on the product label. If your puppy has any ongoing health conditions, a quick chat with your vet can help confirm the best choice.

Ready to simplify your dog's parasite prevention? Shop all-in-one flea, tick, and heartworm chewables at Sierra Pet Meds and enjoy fast, affordable shipping straight to your door.