Does Seresto enter the bloodstream


No, Seresto does not enter the bloodstream. It is a type of flea and tick preventive spot-on that works by releasing an active ingredient into the fatty tissue layer of the skin. The active ingredients in Seresto do not enter or circulate in the bloodstream. Instead, they form an effective flea and tick control system around your pet’s neck with just one application that can last for up to 8 months.

Seresto is made from organically degradable materials and if ingested it does not have any adverse effect on your dog or cat due to its non-toxicity when taken internally. It’s also specifically designed to stay near the surface of the skin, so it doesn’t actually penetrate deep enough to enter into a pet’s bloodstream.

What are the active ingredients in Seresto?

Seresto contains two active ingredients, Imidacloprid and Flumethrin.

Imidacloprid is an insecticide that works by affecting the nervous system of parasites like fleas and ticks. It paralyzes them so they can’t bite or suck blood from their hosts anymore.

Flumethrin is a pyrethroid-based insecticide which works against the same parasites, and also repels them from coming back to the host again, creating a barrier against infestations.

Both of these active ingredients work together to provide long-term protection against parasites. Therefore, no, Seresto doesn’t enter the bloodstream as it only affects the external pests that come into contact with your pet fur!

Why can’t it enter the bloodstream?

It’s impossible for Seresto to enter the bloodstream because it’s designed not to. The active ingredients in Seresto, imidacloprid and flumethrin, are bound together in a polymer matrix so they can be slowly released over time.

This makes Seresto extremely effective – because it prevents fleas and ticks from attaching to your pet – but also keeps it from entering your pet’s bloodstream. If these toxins were present in the bloodstream, they’d cause uncomfortable side-effects that could even be deadly. That’s why this combination has been specifically designed not to enter the bloodstream.

Seresto is designed as an external treatment – meaning only full benefit is achieved when the product remains on the animal’s coat for 8 months without washing away or being removed by physical contact like brushing. This slow release of active ingredients provides continuous protection throughout those 8 months.

What are the potential risks associated with Seresto?

When using a Seresto product, it is important to be aware of any potential risks. It’s true that Seresto does not enter the bloodstream, but there are still several potential risks that you should know about.

First, contact with skin and eyes may cause discomfort or irritation. It is possible for pets to experience dermatitis or salivation when exposed to the collars. This can be avoided if the collar is applied correctly according to the instructions provided by the manufacturer.

Second, ingestion of Seresto can cause toxicity in pets and even death in some cases. The most common symptoms of poisoning include vomiting, diarrhea, difficulty breathing, muscle weakness and disorientation. Additionally, young children and pregnant women should never handle Seresto collars due to potential health risks associated with them.

Are there alternative treatments/preventative options?

While Seresto does not enter the bloodstream, there are alternative treatments and preventative options for flea and tick protection. Depending on the severity of a pet’s infestation, topical medications such as advantage multi and Revolution are popular products that offer protection from these pests. Additionally, oral medications such as Comfortis and NexGard also provide powerful preventive solutions against fleas and ticks without entering the bloodstream.

For pet owners looking for more natural solutions to protect their furry companions from fleas and ticks, there are also herbal remedies like herbal flea collars or herbs like eucalyptus and lavender that have been found to give mild repellent effects. Diet can also be an effective way of preventing pest infestations; incorporating high-quality proteins, essential fatty acids, antioxidants and prebiotics into your pet’s food can help to strengthen their hair follicles which discourages parasites from hitching a ride into your home.


While Seresto doesn’t enter an animal’s bloodstream, it is important to be aware of its ingredients and take the proper safety precautions when using it. Additionally, researching other treatment options can help pet owners make informed decisions about protecting their furry family members.

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