If you’ve had a pet, chances are you’ve suffered with them through a flea infestation. And in that case, these numbers might not surprise you: A single female flea can lay 40 to 50 eggs per day for about 50 days — about 2,000 eggs in her lifetime. The resulting flea larvae nestle deep into fabrics, bedding, carpeting and on your pet to form cocoons (pupae) that can lay dormant for weeks to months.
That’s right — you may kill the adult fleas but unless you target the pupae as well, you’re going to see more fleas in about 90 days.
But fleas are more than just an itchy annoyance. Some pets are mildly to severely allergic to flea saliva and can experience discomfort even from a single bite. Flea bites can make your pet lick and scratch themselves until they develop secondary problems like skin infections, hot spots and even behavior problems like destroying furniture out of frustration.
If a flea infection goes undetected, your pet may develop a heartworm or tapeworm because fleas can carry and transmit their larval forms to pets and people. And although rare these days, typhus and bubonic plague are both flea-borne .
Once you get an infestation, it can be time consuming, expensive and require toxic chemicals to kick. The key to avoiding this hassle is prevention. The development of effective oral and topical spot-on treatments has helped tremendously to break the flea reproductive cycle on your dog. As a result, flea collars have become less popular than in years past — and there is now debate among veterinarians and pet owners about whether flea collars actually work or if they’re just another placebo pet product we’re conned into buying.
With the help of veterinary experts, we dive into the science and pros and cons of flea collars. We’ve also included a few of the best flea treatment alternatives available today.
Understanding the Science Behind Dog Flea Collars
Not all flea collars work the same way. Some simply repel fleas and ticks while others contain pesticides or medications that pass into your pet’s skin, fat and bloodstream. Some flea collars include both. Read carefully before you purchase to understand exactly which features you’re getting.
Repelling collars contain a slow-release chemical that off-gasses to create a constant cloud or “bubble” around your dog that is unpleasant to fleas. These collars generally make fleas jump off instead of killing them. That means fewer eggs are laid in your dog’s fur, but it won’t necessarily keep fleas out of your home. Repellant collars usually have the words “repels” or “wards off” on the label.
Collars that treat your dog for fleas hold medication that seeps into the fat layer of your dog’s skin or have active ingredients that spread using your dog’s natural skin oils. Depending on the chemical on the collar, it will either kill fleas and ticks on contact or only when the flea or tick bites and ingests the pesticides in the dog’s blood. These collars will often include the word “kill” on the label and generally specify if they kill adult fleas, their larvae or both.
Insect growth regulators (IGRs) methoprene and pyriproxyfen inhibit eggs from developing. That means collars that use these chemicals keep new fleas from hatching but don’t directly kill the fleas on your dog. The chemicals permethrin and fipronil kill by affecting the insect nervous system, but don’t directly harm mammals.
Avoid products that use the chemicals imidacloprid or dinotefuran, as they can be toxic to children.
Pros and Cons of Flea Collars
Flea collars are generally easy and convenient to use because they release repellants and/or insecticides slowly, over several months, and are less messy than topical spot-on treatments. They’re also usually less expensive than oral and spot-on treatments on a per month basis. But the least expensive brands are also the ones veterinarians agree probably don’t actually work.
“Flea collars come with a myriad of potential side effects and dangers,” warns Dr. Jamie Whittenburg, DVM, Director of Kingsgate Animal Hospital of Lubbock, Texas, and SeniorTailWaggers.com. “Some dogs will experience skin irritation and rashes in the area of the collar.” Their skin is likely reacting negatively to the chemical insecticide. Discontinue use immediately at the first sign of any inflammation or redness to avoid the possible formation of skin ulcers or infection.
Physical safety is also a concern. “Dogs can be choked or hanged if the collar catches on a cage, fence or other objects, and I have seen many injuries to both the dog wearing the collar and their playmates if a jaw or foot becomes entangled in the collar,” explains Dr. Whittenburg. “I have unfortunately seen it multiple times.”
Dr. Sara Ochoa, DVM, a veterinarian at Whitehouse Veterinary Hospital in Whitehouse, Texas, and SeniorTailWaggers.com, notes that “the downsides to these collars are the high level of chemicals. Most flea collars for dogs contain insecticides, which can pose risks to your family and other pets, so be clear about the active ingredients before buying.”
Pet owners must also consider the smell of dog flea collars. “Many dogs sleep in the bedroom with their owner and, personally, that is the last thing I want to smell all night,” says Dr. Ochoa.
If you have a puppy or younger dogs, there are additional considerations. “Puppies like to chew on things that they shouldn’t, and this even means their collars,” adds Dr. Ochoa. “I have seen many puppies chew their flea collars off. Most of these were not designed to be ingested. When applying a flea collar on your dog, make sure that is for the appropriate size dog. Also make sure that it is snug enough that you can only get two fingers between the collar and your dog.”
The Verdict: The Only Effective Flea Collar Is Problematic
The idea of flea collars can often be an attractive one because some collars can last up to eight months — much longer than oral and 30-day spot-on treatments. But most agree that flea and tick collars are only an option for dogs and cats that are not suffering from an existing infestation. They might be effective at preventing new outbreaks of fleas, but they won’t be powerful enough to rid your pet of these pesky parasites without also using them in combination with other measures and treatments.
“In my experience, the only flea collar I have seen consistently be effective is the Seresto collar,” says Dr. Whittenburg. “These collars contain an IGR and are also long-acting, which aids in preventing and controlling flea infestations. But it is of note that the Seresto collars are currently under governmental regulatory agency scrutiny.”
Dr. Ochoa agrees. “The only one I have found to be effective from having dogs at my clinic use them are the Seresto flea collars.” But, she adds, “I generally do not recommend that people use flea collars.”
Seresto flea collars use imidacloprid, which is a neonicotinoid insecticide, and flumethrin, which is a pyrethroid. Each works by attacking different receptors in the insect nervous system. These collars are regulated by the Environmental Protection Agency, which regulates most flea and tick products applied to a pet’s skin or fur. It is too soon to know the outcome of a class action lawsuit filed against the makers of Seresto, but on March 17, 2022, the U.S. House Subcommittee on Economic and Consumer Policy called for a temporary recall until more information could be evaluated.
Alternatives to Dog Flea Collars
“Fleas are determined pests and often prove challenging to control,” says Dr. Whittenburg. “With an extremely long life cycle, control measures must be multi-faceted, including targeting both the adult and immature stages, environmental control and using control measures for an appropriate length of time.”
SPY has developed this list of top-rated flea and tick treatments that includes a range of product options that can be used individually or in combination.
You can also use safer alternatives as treatments in the home on bedding and carpets. These might include herbal or organic flea sprays, diatomaceous earth, lemon sprays and salt in conjunction with vacuuming.
“But products often touted as ‘all-natural’ are typically ineffective and are often actually toxic, for example, garlic and some essential oils,” explains Dr. Whittenburg. “If your pet has fleas or is in an environment where they may acquire them, talk to your veterinarian about how to proceed.”
1. NexGard Chews for Dogs
Dr. Ochoa recommends a chew such as NexGard. Each chew is FDA-approved to kill adult fleas and ticks for a full month. “I like that there is no oily spot on my dog or a collar that smells bad (and many that do not work at all),” Dr. Ochoa says. NexGard works on puppies as young as eight weeks.
2. NaturVet Herbal Flea Spray
NaturVet Herbal Flea Spray is a preventative spray that was formulated by a veterinarian for both dogs and cats over six weeks of age. The simple, fragrant herbal ingredients — thyme, cedarwood, lemongrass and rosemary oils — are safe to use on bedding and furniture year-round. But as with any product, spot test fabrics in an inconspicuous location before applying widely.
Thyme essential oil is known to help dogs with respiratory issues. The manufacturers say the spray is safe to use directly on your pets as well, but I don’t recommend that use, as lemongrass oil can cause skin irritation and gastrointestinal upset in some dogs and cats.
3. Siyah Organics Artemisia-Annua Powder
Siyah Organics Artemisia-Annua Powder can be added to your dog’s food or water. Artemisia is high in vitamin C to boost the immune system and is known for its anti-viral and anti-parasitic properties. The manufacturers say it can also ease moderate respiratory difficulties.
Siyah Organics Neem Oil
Siyah Organics Neem Oil can be used as a flea repellent on bedding and carpets and is safe to use on your pet’s fur. It is actually good for the skin because it contains essential fatty acids such as omega-6, omega-9 and vitamin E that will also make your dog’s fur shine.
Why Trust SPY?
Lorraine Wilde has had at least two cat and two dog companions in her home for the past 35 years. When researching this piece, Lorraine evaluated customer and professional reviews, the safety and health of the ingredients and materials of each product, and each company’s product research and development.
Because she has only the highest of standards for her pets and her family, Lorraine included products she’d be willing to use in her own home.
Lorraine holds a Master’s degree in environmental science with an emphasis in toxicology. She does this work to help consumers make healthy, informed and environmentally conscious choices to protect their pets, their families and our planet.
Dr. Sara Ochoa, DVM, is a veterinarian Whitehouse Veterinary Hospital in Whitehouse, Texas, and at SeniorTailWaggers.com. She earned her Doctorate in Veterinary Medicine from St. George University and has over six years of experience working in the veterinary field.
Dr. Jamie Whittenburg, DVM, is a veterinarian at SeniorTailWaggers.com and is the Director of Kingsgate Animal Hospital, a full-service animal hospital providing comprehensive healthcare services in Lubbock, Texas. She has been practicing for more than 16 years.