Medically reviewed by Ruffly’s Veterinarian Friends — licensed veterinarians, and pet parents themselves. Last reviewed June 9, 2026.
TL;DR: The best flea & tick preventive for your dog comes down to coverage and convenience. Bravecto (fluralaner) is a chewable or topical that lasts about 12 weeks per dose. Simparica Trio (sarolaner + moxidectin + pyrantel) is a monthly chew that also prevents heartworm and intestinal worms. Credelio (lotilaner) is a monthly oral chew for fleas and ticks. Frontline Gold (fipronil + (S)-methoprene) is a monthly topical. The three orals are prescription isoxazolines; Frontline is topical. All are FDA-regulated and considered safe — your veterinarian helps pick the right fit.
There’s no single “best” — the right choice depends on your dog, your routine, and whether you also need heartworm prevention. Here’s how the four most popular options compare.
This article is educational and isn’t a substitute for veterinary advice. Your veterinarian will recommend the right preventive for your dog’s age, weight, health, and lifestyle.
| Product | Active ingredient(s) | Form | How often | Also prevents |
|---|---|---|---|---|
| Bravecto | Fluralaner | Oral chew or topical | ~Every 12 weeks | Fleas, ticks |
| Simparica Trio | Sarolaner, moxidectin, pyrantel | Oral chew | Monthly | Fleas, ticks, heartworm, roundworms, hookworms |
| Credelio | Lotilaner | Oral chew | Monthly | Fleas, ticks |
| Frontline Gold | Fipronil, (S)-methoprene | Topical (spot-on) | Monthly | Fleas, ticks, chewing lice |
Bravecto, Simparica Trio, and Credelio are oral medications in the isoxazoline class — your dog swallows a chew, and the medication works from the inside to kill fleas and ticks. Frontline Gold is a topical applied to the skin. Oral products aren’t washed off by swimming or bathing and avoid a greasy application site; topicals don’t require your dog to eat anything. Many families simply prefer one route over the other.
Bravecto’s standout feature is duration — one dose lasts about 12 weeks, so you dose roughly four times a year. Bravecto, Credelio, Simparica Trio, and Frontline Gold are all dosed by weight, so the right size matters — check the dog medications pages for the band that matches your dog.
This is the big differentiator. Simparica Trio is an all-in-one: along with fleas and ticks, it prevents heartworm disease and treats common intestinal worms — so one monthly chew covers a lot. Bravecto, Credelio, and Frontline Gold cover fleas and ticks but not heartworm, so dogs on those typically also need a separate heartworm preventive. Ask your vet what your dog needs based on where you live.
The FDA considers commonly prescribed preventives like Bravecto, Credelio, and Simparica safe and effective. In 2018 the FDA issued an advisory noting that isoxazoline-class products (the orals here) have been associated with neurologic signs (such as tremors or, rarely, seizures) in a small number of dogs. Most dogs tolerate them well; tell your veterinarian if your dog has a history of seizures, and report any unusual signs. Topicals like Frontline work differently and aren’t in the isoxazoline class.
Your veterinarian is the best guide — regional parasite risk, your dog’s health history, and your routine all matter.
Flea, tick, and heartworm prevention is a year-round, repeat purchase, so price adds up. At Ruffly you’ll see the price per dose and pack on each product page, our medications are internationally sourced from licensed pharmacies and pharmacist-verified, and shipping is free over $49. The prescription options require a valid veterinary prescription — upload it, have us contact your vet, or transfer it.
There’s no single best — it depends on your dog and needs. Bravecto lasts about 12 weeks; Simparica Trio is monthly and also prevents heartworm; Credelio is a monthly flea/tick chew; Frontline Gold is a monthly topical. Your vet helps choose.
Simparica Trio. It combines flea and tick protection with heartworm prevention and intestinal-worm treatment in one monthly chew. Bravecto, Credelio, and Frontline Gold do not prevent heartworm.
Not “better,” just different. Bravecto’s advantage is convenience — about four doses a year. Simparica Trio adds heartworm and worm coverage. Credelio is a straightforward monthly flea/tick chew. The right pick depends on your dog and whether you need heartworm coverage.
The FDA considers them safe and effective. It has noted that the oral isoxazoline products can rarely cause neurologic signs in some dogs, so tell your vet if your dog has a seizure history and report unusual symptoms. Most dogs tolerate them well.
The oral options (Bravecto, Simparica Trio, Credelio) require a veterinary prescription. You can upload it, have Ruffly contact your vet, or transfer it from another pharmacy.
Compare options on the dog medications page — Bravecto, Simparica Trio, Credelio, and Frontline Gold — or upload a prescription. Always consult your veterinarian about the best preventive for your dog.
